■ ■ ■ ■ ■ ■ ■i-.v-.-. ■ ^^H ■ Class T- S \ $ 8 O Book iSr^ Gojpgltflf COPYRIGHT DEPOSIT. I Goodrich Employees Reading Course Volume V RUBBER IN INDUSTRY A STORY OF THE DEVELOPMENT MANUFACTURE AND USES OF RUBBER BELTING— HOSE— MOLDED GOODS- PACKINGS — FLOOR COVERINGS — MISCELLA- NEOUS RUBBER ARTICLES AND RUBBER INSU- LATED WIRE. ?£6 2 thus giving a greater thickness of rubber cover at the center of the belt where there are fewer plies. The belt may consist of four plies at the center and two additional plies at the edges. When the thickness of cover at the center is &" as in this case, the cover at the top near the edges would be only y%' or perhaps even less in thickness. The theory underlying this construction was that greater thickness of cover could be thus secured toward the center of the belt where the wear on the surface is greatest and at the same time greater flexibility secured for troughing by the stepped arrange- ment of the plies. Now while this idea may theoretically be good, it has not worked out in practice successfully. The actual wear and tear on the surface of the belt is great- est, not at the center of the belt, but along the edges of the load this being not very far from the edge of the belt at each side. This causes the stepped ply belt to wear out more quickly where the cover is thin- nest and where it should be particularly thick to resist this wear. Secondly, there are weak lines along each side of the belt where the ply thickness and cover thickness changes. This tends to cause the belt to crack and the plies to separate along these weak lines especially so when the shape of the troughing pulleys is not just what it should be. If we have, for instance, a belt 36" wide these weak lines may come, say 8" from each side. Then suppose we have a 5 roll trough- ing idler over which this belt is to run. If the spaces between the outer pair of rolls happened to be a little wide and happened to coincide with the weak lines of the belt, the belt will squeeze into these spaces and break down very quickly along its weak lines. 27 Rubber in Industry This has actually been found to have happened in a great many installations where stepped ply belt was originally installed. The result has been that in very few instances where the original conveyor belts have been worn out they have been replaced by the same type. As has been noted before, belt conveyors are em- ployed in thousands of industries and utilized for handling every conceivable kind of material. The more ordinary uses are fairly well known but many will be surprised to learn that belt conveyors are em- ployed in the handling of pills, pins, rubber bands, raw cotton, mail, waste paper, magazines, canned soups and vegetables, phonograph records, wet con- crete, ashes, shoes, hats, automobile parts, and a mis- cellany of bundles and packages in large retail stores. This method of handling products is, however, more extensively employed in the transportation of bulk materials in the following industries than in others, viz., mines, sand and gravel pits, cement plants, paper mills, and bottling works. In its numerous applications the belt conveyor may serve to carry thousands of envelopes away from the machine every hour, or it may hourly supply the stamp mills in a reduction plant with hun- dreds of tons or more of heavy ore. This statement brings us to our main point, namely, that the capacity of belt conveyors is almost unlimited, depending of course upon the width, the speed at which they are run and the weight of the materials transported. The selection of the proper size belt is, however, not a mat- ter of conjecture but on the other hand formulas derived from mechanical calculations and experiences embracing the various factors of a particular applica- 28 Rubber in Industry tion may be used to accurately determine width, num- ber of plies and speed necessary to serve a given set of conditions. For example, the width of a conveyor belt is determined by the following formula. 62,000 G W= Sg when, C=Capacity in tons per hour, S=Speed in feet per minute, g= Weight in pounds of one cubic foot of the material to be handled. To illustrate this formula let us determine the width of a conveyor, operating at a speed of 300 feet per min., to handle 50 tons of coal per hour. Goal weighs 50 lb. per cubic foot. G=150. S=300. g=50 and thus 62000x150 W= or 25" is the width of belt required. 300x50 Using this formula as a basis, by transposition of the equation we may determine the width or speed when the capacity and one of these factors have been pre- determined: W 2 Sg 62,000 G G= S= 62,000 W 2 g As before stated, very little power is required to keep the belt in motion because the load at any given time is relatively small the volume or capacity being main- tained by the speed at which the belt travels which varies from 200 ft. to 600 ft. per minute according to the rolling tendency of the material. The belt is the 29 Rubber in Industry most important factor, but if the idlers are not kept properly lubricated and the head and tail pulleys are not maintained in nearly perfect alignment it may not give satisfaction. Conveyors are frequently located in exposed places and it is not unusual to find a belt drag- ging over dead or frozen rollers which cut the cover and fabric to pieces quickly. Conveyor belts are not quickly worn out by carrying materials but rather by loading; and for this reason, every effort is made to have the bins and chutes so designed and constructed that the delivery of material to the belt will be in the direction in which the belt is moving and at as nearly the same speed as possible. There are, however, several common abuses to which conveyor belts are frequently subjected which when avoided by careful and intelligent handling of the equip- ment result in a considerably extended length of belt- ing service. Some of the most glaring of these are over- speeding, which increases abrasive wear; misaligned pul- leys and idlers which increase edge wear; too much tension which will stretch the belt, pull out the lacings and may ruin the machine under sudden heavy loads; long lay-ups of exposed equipment where the belt is not removed, causes it to deteriorate prematurely by the action of rain, sun, and frost; and lastly, by im- properly installed skirt boards, under which coarse par- ticles of the material may become lodged and by dragging along, cut and injure the rubber cover. Skirt boards are frequently necessary where light or fine materials are handled, such as sand to keep them from spilling over the edge of the belt. These should be flared rather than installed horizontally and then cut away underneath at a slight angle, starting from the back. 30 Rubber in Industry Usually, belt conveyors are installed in a horizontal position but they may also be slightly inclined. The angle of inclination, however, is limited to that at which the material starts to roll scarcely ever exceeding 20 to 23 degrees from the horizontal. The question of power transmission enters into con- veyor belt practice but does not determine the number of plies or weight of the belt as is true in transmission belt construction. Other factors such as belt body sufficient to support the weight of materials carried without excessive sagging between the idler sets de- mand a belt of such proportions that much greater strength is provided than is necessary for the trans- mission of the very small amount of power required to keep the load in motion. On account of the low speed and extreme length of belt, power transmission in con- veyors is, therefore, not efficient. Belt Elevators. When the angle of elevation to which material is to be transported is abrupt or the space limited so that the belt will have to be run at a steep angle, or vertically, buckets are fastened to it and it becomes an elevator instead of a conveyor. On account of the low first cost, economy of operation and dependability, belt elevators are well adapted to the lifting of all kinds of grain, ore and other materials ex- cept in cases where the material to be moved is not loose but must be scraped or dug up as is the case where excavation is made by trench digging machinery. Here, double chain elevators seem to be better adapted on account of the heavy nature of the work. Belt ele- vators are used extensively in many industries but especially in the mining industry where they, with the 31 Rubber in Industry conveyors, are the arteries of the mills. They are the source of a great deal of trouble and no effort is spared by the careful mill owner to make his elevators as nearly ideal as possible as far as the equipment is concerned. The belts are subjected to all manner of abuses and if one fails unexpectedly, the ore circulation of the entire plant becomes clogged causing a complete shut-down. One sudden shut-down through belt failure, will very likely cost in lost output, extra labor, superintendence and repair expense, more than the cost of several good belts or even an entire elevator equipment. The difference between elevator and conveyor belt requirements should be evident. But to make certain that our reasons are understood thoroughly by even those who have not heretofore come in contact with elevator belt practice we will mention that this service is by far the most severe to which belts are ordinarily subjected. Therefore, to provide against the losses of delays incident to frequent breakdowns, elevator belts are built stronger and heavier than those used in con- veyor service. Elevator belts are also made up of a greater number of plies so that they will withstand the breaking effort of bits of stone, etc., which are bound to get caught underneath and pass around the pulley; and as an added reason, to afford sufficient anchorage for the bolts or rivets which hold the buckets in place. The backbone of an elevator belt is, in fact, its fabric structure and sufficient strength must be built into the body in order to offset the weakening due to the bolt hole punchings and the resultant action of moisture. Elevator belts sometimes run through water and frequently handle wet materials continuously. Natur- 32 Where Goodrich Belts are Vulcanised #? " A Gold Dredge As Rubber Belting Predominates in the field of Power Trans mission Conveyor Belts afford the most practical means of handling materials over short distances up to about 1000 feet An Incline Coueyov The driving and Driven. Machines TYPES - 1 Rubber Covered ■ — ^Friction Surface — ■ 5 Stitched_ apd Rubber Covered — ^High Speed, Small Pulley — -Gum Cu?hio, Rubber in Industry ally the severities of such service must be provided for in the quality of friction as well as in quality of fabric. In other words, the presence of fabric quality alone will not do the trick; but in order that ply separation may be prevented and as a consequence, the belt other- wise good be made useless, a high quality of friction rubber must be present. Only by such a balanced con- struction can the belt manufacturer hope to deliver a dollar in service for the dollar spent. Balata belts, woven belts, and impregnated canvas belts of many types, have been experimented with in various fields but in the main have proven to be dismal failures for the more severe belt elevator service. In other words the rubber belt is the only type which has ever demonstrated its economical value in actual serv- ice, giving uniform satisfaction. Mill-men generally stick pretty closely to the high class rubber belting for elevator work for experience has shown that the better the belt the cheaper it is in the end. There is no question but what with a good belt the number of in- terruptions is materially reduced. Rubber covered elevator belts are coming more and more into general use. On the pulley side, the smooth surface thus gained increases the co-efficient of friction and prevents belt wear from the particles of material which get between the driving surface and the foot or '"boot" pulley. The degree of wear in this instance is, however, somewhat dependent upon whether the ma- terial is dropped into the boot and scooped out by the buckets or poured into the buckets directly. A rubber cover on the bucket side also prevents abrasive wearing of the belt from particles of material which are nearly always bound to get between buckets and belts, thus 33 Rubber in Industry subjecting the surface to a grinding action from the moving of the buckets as they pass over the pulleys. In some instances these rubber covers have, according to mill men, not proven practical but we are, however, of the opinion that this is because the right specifications were not worked out for the particular service require- ments. It has been claimed by some that the rubber on the back of the belt is of doubtful value because a few weeks hard service peels it off exposing the canvas. To us this statement seems an impeachment of the adhesion between the particular rubber cover used and the duck rather than an argument against the use of the rubber cover. Why should not conveyor philosophy apply in elevator belt practice? Goodrich Elevator Belting, the same as our conveyor types embodies the latest developments in the manu- facture of rubber belting for this particular service. Our engineers have made a careful study of the con- ditions surrounding the operation of belt elevators in various industries and our constructions have accord- ingly been especially adapted to the service as it exists. In selecting the fabric we have considered the strength necessary to guard against the pulling through of the bolts and we have furthermore developed a weave which affords the necessary body at the same time permitting the rubber compound to permeate each strand and sur- round the threads with a frictionless covering of rubber. The Goodrich organization has probably analysed the performance of more mining belts in actual field service than any other manufacturer. The result is common sense practical construction along with properly balanced rubber and fabric of the correct quality for each particu- 34 Rubber in Industry lar service. This common sense construction has developed a product embodying the following advantages: In general Maximum flexibility. Sufficient strength for every require- ment. Very little stretch. Great endurance. Will not break before it is worn. In fabric Toughness and durability. A secure anchorage for bolts and rivets. A body that bolt holes will not weaken. In friction Insurance against ply separation. Exceptionally long life. The best protection against moisture. Gives the belt extreme pliability. In cover Protection to the fabric and friction. Toughness and resiliency. Wear resistance. In service Belts which are rendering excellent ac- counts of themselves. Almost every day we learn of new uses for belt con- veyors and belt elevators. Furthermore, their advan- tages over other methods of short distance transporta- tion are so pronounced that it is reasonable to anticipate a broad expansion in this field already extremely at- tractive to the belting manufacturer. The B. F. Good- rich Company claims the distinction of having built the first conveyor belt for the inventor and patentee of this useful device — the conveyor; and, through develop- ments based on experience with conveyor and elevator operation all over the country we have up to the present been able to maintain the leadership in the production 35 Rubber in Industry of a high quality belting for these uses. We do not, however, manufacture idler rolls or other accessory machinery. Brands. In accordance with our established policy each brand in our belting line whether transmission, conveyor, or elevator construction, stands for a particular, and in many instances a special development designed to meet certain conditions. Each of our brand names is well known to the trade and new and catchy trade- marks are never employed to mislead the trade or deceive the consumer. In a work such as this, however, a full description of brands and their peculiarities in ap- plication would be of little practical value and for this reason there is little else beyond the thought just ex- pressed which would add to the value of this discussion. We may mention, however, that the standardization of our line is a constant source of pride to our sales organ- ization. Even from the very brief descriptions which we have been able to allot to the three sub-divisions under this general topic of belting the reader has no doubt seen that success in this field depends primarily upon build- ing belts which will satisfy particular service demands, and, having built them in seeing to it that the right quality and brand is sold for each installation. At least this is the thought which we have intended to develop and with this in mind we have from the be- ginning not only constructed our product but have trained our men to make common sense recommenda- tions in selling. When one considers, however, that nearly every shop or factory of any description is literally laced down with a maze of belting, only then 36 Rubber in Industry can conditions encountered in service commence to be realized. Not only are lathes, planers, shapers, looms, and thousands of other machines driven by belts but as we have mentioned, materials are carried from floor to floor or from building to building by belts either with or without the aid of buckets. There is yet another thought in this connection which when extended by further reflection may serve to ex- plain to those who have just arrived, the fundamental reasons back of our manufacturing and selling policy. This is the fact that we construct to exceed require- ments not merely to meet them, which explains clearly the reason for the reputation we have gained in this belting field. Our customers are assured of the very best product that close study of conditions, expert se- lection of raw materials and modern manufacturing equipment can produce. When the Goodrich or Dia- mond trademark or brand appears upon a belt they know that it is a guarantee of protection and that our reputation for high grade goods and square dealing in this field has been maintained over a period of a half century, that every brand which is stamped as our product is done so with the realization that we must live up to that reputation. Every item in our belting line stands as a representative of the highest standard of service value in its respective class and we in all instances stand back of the brand. Aside from our numerous standard constructions as furnished for these three service requirements, i.e., trans- mission, conveyor, and elevator, we manufacture special belting for oil well drilling, polishing machinery, car axle lighting systems, animal dehairing machines, etc. But inasmuch as these are special constructions, de- 37 Rubber in Industry signed for peculiar service requirements, although con- structed and employed similarly to standard belts, we do not believe it advisable to describe them individually in this work. For convenience in handling, shipping, and selling, all belting, of whatever nature, is packed in rolls. 38 CHAPTER TWO Rubber Hose T~\EFINITION. The word hose as used throughout *-J this work designates a flexible pipe for conveying fluids, air and other gases as well as dry sand, powdered materials and sometimes wet earth. To be universally acceptable this type of conveying medium must not only be capable of bending without breaking or col- lapsing, but must also possess endurance and the quality of lightness that it may be easily handled yet perform severe service. In addition, the construction of hose must be simple in order that it may be sold at a reason- able price. Iron, steel, copper, brass and lead piping are flexible to a limited degree, especially the latter; in fact, this material is frequently employed where the positions of two connections are not fixed nor constant. But pipes made of metal do not long endure constant bending and will not permit cold bends or short radii without permanent setting, collapsing or breaking. In the all-inclusive sense of the word, herefore, hose may be made of almost any material; but fabric and rubber in various combinations are by far the most extensively used. In fact, with the exception of a metallic conduit made of helically wound interlocking strips of metal with asbestos or some other fibrous material interposed between the spirals to effect a seal, a small amount of linen and cotton fire hose, Rubber Hose may be considered the universal standard flexible medium for conducting fluids and gases. The metallic 39 Rubber in Industry helix variety is used to a limited extent for short steam connections; but this type is, however, extremely ex- pensive and its use therefore, confined to a small field of application. Woven hose of cotton or linen has had a wide distribution especially for fire-fighting purposes, but is not acceptable in the greater majority of uses where a flexible conducting medium may be employed to advantage. Rubber hose, so termed, i.e. that con- structed from compounded rubber and rubberized fabric either in the form of a wrapped or braided carcass can therefore, be said for our purpose to define the word Hose. Historical. Throughout the early history of me- chanics, frequent references are made to flexible pipes made of rawhide or leather for the purpose of conduct- ing liquids. Leather in fact occupied a very important position in the list of hose materials even as late as 1859. Beginning, however, with this date, its use com- menced to decline until today this material is no longer thought of in this connection. There seemed to be no general type of construction, but the most common variety was produced by the expedient of building strips of leather over a mandrel or form and then sew- ing the edges together. As may be imagined, however, leather hose never proved satisfactory from a practical standpoint and was at best found to be only a make- shift. Even as early as 1827, Hancock and Macintosh had introduced into Europe a hose made of India rubber and fabric. Hancock's Personal Narrative, The Manu- facture of India Rubber, describes the early processes employed by them in such an interesting way that we 40 Rubber in Industry feel justified in incorporating at this point a brief para- graph or two from his description. "We manufacture hose-pipes and tubing of caoutchouc, gutta percha, and compound in various ways. We take threads made of either of the above, of a size propor- tioned to the hose, and braid it upon a core formed of rope which has previously been coated with treacle and glue, or glue and whiting, and made perfectly smooth. The braiding may be repeated, or a coating of either of the solutions may, if necessary, be given, and when dry, rolled under pressure with a gentle heat; we finish by immersing the whole, and thereby produce the 'change' and unite all the coatings; the core is after- wards removed by boiling in water. For fancy tubing the threads may be of various colours. By another mode, we take woolen or worsted yarn, of size propor- tioned to the strength of the required hose or tubing, and saturate and coat it with a solution of caoutchouc, gutta percha, or a compound thereof, until the fibres are all covered, and when dry we braid it upon a core as above; we then roll it under pressure with heat, or, if necessary, give it a previous coat or two of either of the solutions, and then immerse it to produce the 'change.' We manufacture these articles also by winding these threads or narrow strips spirally round the core, keeping the edges quite close, and, if necessary, wind another tape or thread over the first in the con- trary direction; we then roll them well under pressure and heat and immerse them to produce the 'change' removing the core as before mentioned." It is evident from Hancock's reference to the word "change" in his description, that this method of con- 41 Rubber in Industry struction was in use in Europe after the discovery of vulcanization by Charles Goodyear. The first rubber hose manufactured in this country following the year 1839 was, however, of a different character in that it consisted of a long tube of rubber incased in a rubber treated fabric jacket and sometimes overlaid with a rubber cover. The jackets were formed by weaving, on a flat loom, strips of cotton fabric the widths of which were proportionate to the circumference of the hose desired. These strips were afterward impregnated with rubber or some rubber compound by a calendering process being subsequently wrapped concentrically and one at a time around the tube previously placed over a metal mandrel. All plies were laid in such a manner that a lapped seam resulted and were joined and held in place by substantial copper rivets spaced at intervals the length of the hose. This was the essential method of manufacture up until the year 1877 at which time B. L. Stover designed a cir- cular loom upon which could be woven a seamless tube of cotton a process which has ever since been employed extensively especially in the construction of fire hose. In fact, this woven type is very well adapted for hose of large diameter and a major portion of the present volume in fire and mill hose is today constructed after this manner. In common parlance, Stover's idea embraces what is known as Cotton Rubber Lined hose but many varia- tions of the woven jacket idea have been introduced including the type known as the multiple woven cover in which two or three jackets are woven together in one operation, which type is, by the way, of doubtful value. 42 Rubber in Industry The basic patent of Stover, however, embraces an im- portant principle of present day construction. While woven jacketed hose was being developed great improvements were also being made in the method em- ployed for the manufacture of so-called wrapped duck hose. It was discovered that by applying the layers of rubberized fabric in a continuous piece by winding around the tube using cement to hold the plies of the wall together that it was not necessary to use rivets or other forms of fastening. Thereby, the cost of manu- facture was appreciably reduced and the serviceability of the finished product at the same time greatly ex- tended. The most marked improvement in rubber hose construction was, however, the Braided method begun in 1908 whereby the cotton reinforcement around the tube of rubber compound is applied after the manner that ribbons are braided on a Maypole. This method is purely a machine process by which it is possible to build pieces of any length and for some purposes at a considerable increase over the other types in manufac- turing efficiency. Since, however, all three methods, perfected and im- proved, have prevailed it can be said that the manu- facture of hose is today divided into three general classes, viz., Wrapped Duck, Woven Jacket and Braided constructions. There is, however, a further classifica- tion which may embody any two of these basic princi- ples. In other words, a combination of Wrapped Duck and Braided construction is frequently employed and thus can we rightly classify hose according to its method of construction into four groups. The peculiarities in- cident to the manufacture of these types we will treat 43 Rubber in Industry individually in paragraphs to follow taking each up in the order we have mentioned them. A volume of considerable size might be written concerning the history of the development of these hose types, especially, could we gain access to the stories of their adaptation to the present day multi- tudinous field of usefulness. This information is, how- ever, impossible for us to gather and suffice it to relate that during the past 25 or 30 years the use of hose has been extended into nearly every industrial activity and to every quarter of the globe. By way of illustration we may mention that today the Goodrich Company manufactures more than 40 different purpose grades and there are doubtless, others not embraced in our list. This company has specialized in the manu- facture of rubber hose for 50 years; indeed the present reputation which the products of The B. F. Goodrich Company enjoy is founded on the brand White Anchor one of Dr. Goodrich's very early products. White Anchor hose, in fact, enjoys the distinction of being the first really serviceable, flexible conductor of fluids offered to the trade and this brand name even today represents the acme of perfection in hose building. This brand is still constructed much the same as it was when Mr. Wheeler established for himself such an envi- able reputation as the first Goodrich Salesman. Today, our Hose Department production facilities, which are almost beyond the comprehension of the lay- man, represent a steady year by year growth until we are considered as ranking first among the companies in the United States in volume of output when all types are embraced; which growth we may safely claim, is 44 Rubber in Industry the logical sequence of the good-faith principle of con- struction initiated by Doctor Goodrich fifty years ago. We realize that production figures when given in feet or in fact in any unit, usually mean very little to the average layman since so very many different sizes, weights, and grades are manufactured; and yet, in spite of this we would be remiss should Ave allow our previous statement to pass without giving more substantial evidence of the magnitude of this division of our business. We, therefore, merely mention that our daily capacity in all sizes and kinds is more than two hundred thousand linear feet, and this production figure, we may say, will hardly stand correct much longer than it takes to tell. Although in keeping with the trend of the times standardization in Goodrich hose construction is the watchword there is even now a grade in our line adapt- able to the conditions of almost any service known in which hose may be employed. Our present grades and types for various purposes have been steadily developed in construction detail in order to produce the most efficient and economical results in each field of service. They are not theoretical but practical grades worked out through extensive study and experimentation. Characteristics of Rubber Hose. There are four general component parts into which a hose may be divided, viz., the tube, the fabric plies, the rubber cover and the protective covering, each one of which must be especially developed and designed to meet the service conditions in each particular kind of applica- tion. The first three are always present but the fourth may or may not be necessary. 45 Ritbber in Industry (1) The Tube. Inasmuch as this component part is the real container of the fluid it is necessarily always present; and the rubber compound of which this part is manufactured must as inferred be made up of such ingredients as will be best suited to the demands of each peculiar service requirement. In other words a hose employed for the conveying of domestic liquids such as vinegar must be provided with a tube the compound of which is entirely free from poisonous in- gredients, the tube of oil hose must be so compounded as to resist the action of this enemy of rubber, the tube of a sand blast hose must be made extremely tough so as to resist the abrasion of the swiftly flying particles of sharp grit and so on down through the 40 different purpose constructions. There are, however, two general methods employed in the manufacture of hose tubes, viz., hand and machine. The stock for hand-made hose tubes comes from the calendering room in multi-ply flat sheet form which is to say, it is composed of sheet rubber that has been built up layer upon layer rather than being calendered to the required thickness in one operation. This method as will be recognized, prevents defects; one ply covering up any slight imperfection which might occur in another. Tubes from this calendered stock are either shaped around mandrels — i.e. smoothly finished iron rods or steel pipe approximately fifty feet long — or, are formed without the aid of this appliance by a system peculiarly all our own, this however depending upon the nature of the stock used and the type of hose for which the tube is intended. But, regardless of this feature, the operation is accomplished much in the same way; which is to say that the edges of the flat 46 Rubber in Industry calendered sheet are brought together in a lapped seam. This seam, during the vulcanization process, joins firmly together making what is in effect a one-piece tube. Machine-made tubes are those constructed on the standard mechanism known as a "tubing" or "spewing machine," a device which in shop parlance is generally referred to as a "sausage machine." The stock from which machine-made tubes are manufactured does not come in calendered sheets but on the contrary is sup- plied directly from the mill room in "batch" form; i.e. in thick slabs resembling sides of sole-leather. This material is cut into strips and fed into the hopper of the machine being forced into the form of a tube through a slightly heated die by the spiral worm. Recent im- provements in the construction of tubing machinery have enabled us to advance the art of machine tube making until it is now possible to produce hose tubes for most purposes which are just as satisfactory as the hand-made type and with the added advantage of a considerably lowered manufacturing cost. In conclusion of this rather brief description of the construction of hose tubes, there is one point particu- larly which we desire to emphasize and this is the necessity of so constructing the tube that a hose with a smooth interior surface results, offering as little re- sistance as possible to the flow of liquids. Particularly so is this an important factor in fire hose where it is desirable to maintain the greatest possible nozzle pres- sure and velocity. Through the rough inner tube the loss of pressure in a fire hose may sometimes reach as high a value as 25 pounds in 100 feet, which factor of loss develops a serious problem, especially in the smaller 47 Rubber in Industry cities where the water main pressure is relatively small and not supplemented by pumping engines. Hand- made tubes are, however, used only in the higher grades of large diameter hose such as is employed in fire fighting, etc. (2) The Fabric Plies. As is the case with many other rubber products the strength of hose is pro- vided by a fabric carcass. Cotton, on account of its ability to undergo the processes which rubber must pass through and because it will withstand the heat of vul- canization with a minimum loss in tensile strength is universally used as the carcass material for this product. As before mentioned, however, the manner in which the fabric is applied as well as the strength of the carcass is in a great measure determined by the pressure to which the hose will be subjected. Moreover, selection of the proper carcass material for each purpose hose, we may further mention, constitutes one of the great problems in hose manufacture. This we may perhaps better illustrate by citing and explaining the rule in wrapped duck construction; which is that the number of plies does not by any means indicate the strength of the hose. In other words, by skimping on the fabric unscrupulous manufacturers may offer at a very low relative figure a hose of an equal or even greater num- ber of plies which will apparently be indicative of the proper quality and strength for the purpose desired, and through this practice be able to exploit the trade of some jobbers and consumers. Need we mention that such a practice of substitution is not worthy of the term competition and will in the final analysis, revert to that maker's discredit. Light material may, how- ever, be used where a flexible, light-weight hose is de- 48 Combinaiion ^Cotton Rubber Lined Type Single Jacket Type cotton m ##iir Rubber Lined Type ^jgj Double Jacket Style. ^M Braided Type. Spra.y . Wrapping Air Brake Hose with Wet Cloth preparatory to vulcanisation rneurrii Braiding Machines SPECIAL COVERINGS* Woven Marlin Jacket Asbestos' Wire Wrapped Rubber in Industry sirable, but such material whenever employed by us in the manufacture of a light-weight hose is always of sufficient body to qualify for the service desired and the hose is sold at a price based according to quality and its intended use. (3) The Cover. Some types of hose, as for example, woven jacketed construction are not supplied with a cover of rubber but on the contrary have their fabric carcass left exposed without protection of any kind. Ordinarily, however, this construction will not suffice for the rough usage which hose is given and a rubber cover is, therefore, placed around the fabric in order that the latter may not come in contact with agencies such as rock, oil, steam, water, etc. To better illustrate this we call attention to the demands incidental to creamery service where hose is continuously subjected to the action of water and grease and point out that the woven cotton jacket under these conditions would last but a comparatively short time. The nature of the cover, therefore, must be governed entirely by service conditions. It does not, however, necessarily follow that the cover stock bears any definite relation to the compound as used in the tube; as for example water hose used in a packing plant must have a cover com- pounded to resist the action of excessive abrasion caused by the hose being dragged over cement floors and around boxes and barrels ; while the tube may never come in contact with anything more injurious than hot water and, therefore, may be of a simpler formula. Rubber covers are either applied in sheet form by being fastened to the end of the duck and wrapped around the hose with it; or in tubular form built over the fabric carcass through the employment of the regulation tub- 49 Rubber in Industry ing machine. Covers are usually -st inch in thickness, but may be made in any gauge desired. (4) Gapping. One advantage in favor of Wrapped Duck construction is the fact that being made in 50 feet lengths, capping for the ends may be applied dur- ing the building up process whereas if this feature be desired on a section of Braided Hose it must be sup- plied after the hose is otherwise completed and cut to length. The term capping infers a ring of rubber com- pound placed over each end of a length thus covering up the plies which would otherwise be exposed. Ex- posed plies allow moisture, oil, or other chemicals to come in contact with the fabric which acting as a wick would carry these liquids on up between the plies in time, dissolving the friction and thereby cause the ends of the hose to fray or blow out at the couplings. Gapping is, however, not always essential and in many instances the extra cost incident thereto is not justifiable. This latter reason is the more important when considering Braided construction because this type is rarely used in the length in which it is manufactured, i. e., approx- imately 500 feet. (5) Protective Coverings. Certain types of hose such as pneumatic-tool for example are constantly sub- jected to conditions of service where abrasive wear and abuse are so severe that the rubber cover does not afford sufficient protection. In such instances it may be economy to provide some additional protection. This feature known as "protective covering," is applied in several different styles such as duck, asbestos, woven cotton, woven marlin and wire helix. Pieces of old sail cloth or other fabric cut into strips and wound around the hose constitute the first type of cover and 50 Rubber in Industry while of questionable value as a protection against abrasion these makeshifts usually cause the failure of a great deal of steam hose by preventing free radiation of the heat from the cover. Asbestos while fireproof is not a good heat insulator as is commonly supposed, and of very little value when used as such. Asbestos coverings therefore, as com- monly employed have little or no value. This material is, however, an excellent flame resistor and should be applied wherever the hose is to be used in extremely hot places such as coke ovens, furnace pits, etc. This style of covering is merely wrapped around the hose and must always be supplemented by wire windings to hold it in place. It is not practical to apply an asbestos covering intended to adhere permanently without such further reinforcement. Painted Woven Cotton covering consists of heavy strands of cotton yarn woven tightly together around the outside of the hose being afterwards coated with some form of paint. The paint enters the fiber and the openings between the warp and weave and provides a certain protection against moisture with its consequent deteriorating action; and, being woven the rupture of one or more threads will not cause the jacket to unravel as is the case when twine is simply wound around the hose. This type of covering is a very serviceable pro- tection against abuse and where employed a lighter hose construction may be used for a given service. The woven marlin type of covering is made on a circular loom just as are all other types of woven jackets, the only difference being that the strands are of hard marlin twine. Marlin is an exceedingly strong twine treated with tar and other substances which permeating 51 Rubber in Industry the fibre, make it resistant to the action of moisture to a practical degree. Marlin twine is also frequently wound around hose but may be easily destroyed by the cutting of the cord at one point. Wire winding is supplied where hose is to be sub- jected to any considerable dragging over rough ma- terials and serves as a protection against extreme abrasive wear and against kinking. Wire winding should not, however, be recommended where the hose is likely to be crushed; on account of the fact that a bend in this heavy wire will not permit the hose to return to its normal shape, thus would it be pre- vented from conveying its capacity. There are three types of wire commonly used in this style of protection viz., round, flat, and half round. The wire is not wound closely over the hose but applied in the form of open helix with considerable space left between each turn. It will readily be seen that in certain places such as stone quarries, sky scraper construction, mines, etc., that wire winding may perform a very valuable service toward prolonging the life of the hose itself. The Manufacture of Rubber Hose. As we have previously inferred in this chapter, manufacture of rub- ber hose is carried on under different processes accord- ing to four standard types of construction generally classified as Wrapped Duck, Braided Carcass, Woven Jacket and Combination. Therefore, in describing the variations incidental to the manufacture of these we will treat them under the captions as enumerated without again referring to classification. (1) Wrapped Duck. This hose comprises that which is made up with a compounded rubber tube supported and strengthened by two or more windings or plies of 52 Rubber in Industry bias cut woven fabric, held together by an elastic bond of "friction" and usually though not always protected by an outside layer of compounded rubber. Wrapped duck construction is the oldest and commonest method of manufacture and is employed in the production of every sort of service hose. Although in some fields it is rapid- ly being superseded by the Braided type, the wrapped method still prevails in the manufacture of a large part of the total hose volume marketed today. There are several reasons for this some of which will be mentioned later; but that we may illustrate our statement, two will suffice, viz., these are that some compounds will not work well in the braided construction, and special purpose sizes may not always be possible to construct except in the wrapped duck way, where mandrels are the only part of the equipment necessary to change. All fabric which forms the supporting walls of this type of hose is as may be supposed, purchased accord- ing to specifications, predetermined in a great measure by what pressure the hose is designed to withstand and by the use to which it is to be put. The weight and weave depend upon the degree of flexibility desired. In other words, if a strong flexible construction is necessary as in pneumatic-tool hose a greater number of plies of lighter duck will be employed; whereas under con- ditions where strength but less flexibility are required a heavier duck of lesser number of plies will be employed. When the fabric employed is under 8 ounces in weight it is termed sheeting but otherwise may be classified as a duck. All hose fabric after being inspected, tested and thoroughly dried, is twice run through the calendering process and thereby receives a frictional coating on 53 Rubber in Industry both sides. Sometimes also an additional "skim" coating on one side is given by passing the frictioned stock through the calender the third time. This rubber impregnated and rubber coated fabric is then cut on the bias, into relatively small parallelograms, and these spliced together into pieces approximately 50 feet long and of a width sufficient to form the number of plies or wrappings desired in each particular case. These spliced lengths are then wound onto shells and transported to the building department ready for use. The next step is the preparation of the tube which as previously described, may either be hand or machine made. These as soon as made are pulled over mandrels and trans- ported to a building table where the rubberized fabric which is to form the plies and the sheet stock which is to form the cover, if such is to be provided, are applied in one operation very quickly by simply revolving the tube on its mandrel between two iron rollers at which time the fabric plies and rubber cover are fed on and wind themselves around the tube automatically. These are smoothed down and rolled tight by a third pulley which is brought to bear upon the mandrel from above. The hose is now completed insofar as the building is concerned and upon being released is transported to another bench where it is again caused to revolve rapidly at which time long strips of wet muslin which are later to play an important part during vulcaniza- tion are wound tightly over the surface. The hose still on mandrels is now racked up, loaded on cars, shoved into horizontal heaters, so termed, and there subjected to the action of live steam under a working pressure sufficient to bring about that change between the rubber and sulphur which turns the compounds from a sticky 54 Rubber in Industry mass into a tough resisting product. The wet muslin strips during this process serve to hold the various component parts in their proper relationship until the change has taken place whereby they are fused into an integral. Following the completion of the cure the muslin strips are unwound, the hose slipped from the mandrel and couplings applied whereupon the product is ready for the market. Branding is accomplished by the use of rubber and metal matrices which have previously been applied to the outer surface during the building up process. Although the manufacture of wrapped duck hose in- volves a great deal of hand work and close attention its simplicity of construction recommends it to the small manufacturer on account of the negligible amount of special machinery required in its production. In addition to this feature wrapped duck hose is advan- tageous because being cured on mandrels, even in the richest compounds, a smooth tube offering minimum resistance to the flow of liquids etc. is thereby produced; a feature which is otherwise not always possible. On account of the difficulties attending the handling of longer mandrels this construction is limited to lengths of 50 feet but in sectional diameter, however, the size is virtually unlimited. This is another great advantage in favor of the wrapped duck method and the one which is doubtless chiefly responsible for a continuation of this type in the face of the advantages presented in the manufacture of the Braided type. (2) Braided Hose, so termed, is that construction in which the rubber tube is strengthened and supported by plies of braided cotton threads. It may be made in one-braid, two-braid, or three-braid construction, ac- 55 Rubber in Industry cording to the number of times it passes through the machine which process of manufacture may be briefly described as follows, beginning with the tube. This part is of course produced on the standard "sausage" machine, in a piece either 250 or 500 feet long the whole length being at the same time coiled on a stand with a circular revolving top. Because it may have occurred to some to inquire how it is that the walls of this green, i.e. uncured tube do not collapse at points, thus rendering the whole piece unfit for further treatment we will, by way of explanation, mention that all during the process from the very start a slight air pressure is maintained within the tube which serves the purpose of the mandrel, keeping the walls distended to their normal size and shape. This inflation pressure which holds the hose to normal size and shape is in- creased to overcome the resistance of the braid after the first ply has been imposed. These tubes are first fed vertically into the braiding machines from under- neath; and spool carriers passing in and out around each other according to the same plan as followed in braiding a Maypole so feed the yarn as to cover the tube with jackets or socks of fabric. There are either 24, 36, or 48 of these spools according to the cross sectional size of the hose desired. Upon completion of the first braided ply the standard tubing machine is again re- sorted to, the tube and single ply of fabric being passed through this mechanism and thereby receives a thin insulation of rubber compound. As this now partially constructed hose issues from this machine it is at once wound upon a drum and again taken to the braiding reel where the second jacket of cotton fabric is sup- 56 Rubber in Industry plied, and this procedure is repeated until the length is built up to the required number of plies. When this point has been reached, however, the thick- ness of the last rubber coating is so increased as to form not only an insulation for the last braid but as a pro- tective covering for the whole hose. An inspection, by the way, is made during each step to insure perfection. In its now completed form, each length of braided hose is run through a tub and there given a dry bath of soapstone. At the same time a "cover pricking" is given which is to say the hose is passed between spiked pulleys which very slightly puncture the cover in almost numberless places, thereby destroying air pockets which might have formed between this member and the out- side braid; a precaution taken to prevent cover blisters forming during vulcanization. The soapstone placed on the cover is, of course, also a precautionary measure to prevent sticking to the mold in which the hose is cured. This operation having been accomplished the hose wound upon the drum ready for cure is transported to one end of a 20-foot hydraulic steam-heated press. Here, together with some four or five other similar pieces it is drawn through between the jaws where the cure is accomplished. This is done section at a time. Air pres- sure, of course, is maintained within the hose during this step which serves to keep the walk distended to the contour of the mold where the cover receives the pat- tern desired from a design which has been ma- chined on the mold interior surface. Braided hose can be manufactured in any length de- sired, limited only by the facilities of the factory for handling through the various steps. General practice, however, se^ms to dictate that for convenience in hand- 57 Rubber in Industry ling, all sizes of 1 inch and under — inside diameter — should be made in 500 foot lengths and in sizes over 1 inch up to and including 1^ inch inside diameter in 250 foot lengths. In 2 inch this type is cut into lengths of 50 feet and cured on mandrels in open steam hori- zontal heaters the same as hose of the wrapped duck construction. This variation from usual practice is fol- lowed for no other reason than because the demand for braided hose in sizes larger than lj inch is so limited as yet to make impractical the installation of machinery for the handling of these larger sizes in greater lengths. As mentioned heretofore one principal advantage of the Braided type of hose lies in the fact of its being strictly a machine-made product. There are, however, other advantages; which is to say this type can be fur- nished in any length required which eliminates the neces- sity for frequent couplings where lengths of more than 50 feet are desired. Moreover, braided hose is on account of the peculiar method of construction used, free from kinking and will not become destroyed so easily when the cover becomes worn off as will the wrapped duck type when the fabric becomes exposed. For these reasons alone this type of construction has become exceedingly popular; so much so in fact that were it not for the advantages presented by the wrapped duck method in the construction of odd lots in a wider range of diameters and grades it is safe to assert that this braided method would entirely supplant the other. Tubing, also in small sizes, such as used on tire in- flation pumps, gas lamp connections etc., although not covered by the general title of hose, is also made accord- ing to the same process except that the cure does not take place on presses. 58 Rubber in Industry (3) Cotton rubber lined. Where high pressures are to be encountered and where also extreme flexibility and light-weight hose are desirable a rubber tube surround- ed and supported by a tubular woven cotton jacket, either protected or unprotected, is a superior form of construction. This type, known as Woven Hose which although largely confined to fire-fighting purposes is nevertheless, sometimes furnished in small sizes for garden or other water hose purposes. Woven jackets for hose are also occasionally employed in combination with a Wrapped Duck construction. In all cases these are woven on what is known as circular loom machines which carry the warp, unbroken, around continuous spiral filler threads which run from one end of the jacket to the other. Any length of jacket may be woven but on account of the difficulty involved in handling longer sections 50 feet in this country seems to be about the limit. Usually, however, when used in connection with municipal fire-fighting purposes one jacket is pulled into another, thus forming what is commonly termed as double cotton jacketed, rubber-lined fire hose. In sizes above \" inside diameter, the tube and jacket are constructed independently being afterward pulled together. In other words, the jacket material as it comes from the loom is cut to the proper length, treated by a special process to eliminate twist and shrinkage. Following this, the rubber lining or tube which has been built, semi-cured and coated with a plastic rubber backing is pulled into the jacket and there given the final cure. This last operation of course joins the tube and the jacket into an insepar- able unit. 59 Rubber in Industry In the manufacture of the f" inside diameter woven hose a somewhat different procedure is followed in that the tube itself, which in this case is always machine- made, is fed through the loom from the bottom, the jacket thereby being woven directly upon it. This is accomplished much in the same manner as the tube is fed into the Braided hose machinery. If this size is to be a double or triple jacket construction, the extra covers are pulled on afterward and are not fastened to each other except at the ends where they are clamped into the couplings. Herein lies the difference between our method of construction and those manufacturers who exploit a type known as Multiple Woven Cotton Jacketed hose which combines the two or three jackets into one simultaneously woven combination. This lat- ter plan of construction is, by the way, extremely more costly besides having no advantages to justify the ad- ditional expense. Cotton Rubber-lined hose, as the product of this form of construction is frequently termed, has for ordinary uses some disadvantages. Chief among these is that the jacket must be thoroughly dried after each period of use. Otherwise mildew will gather, causing rapid dis- integration. To obviate this difficulty where a woven jacket hose is desired above other types of construction a rubber cover is sometimes applied over a single light weight woven jacket producing what is known to the trade as Cotton Rubber-lined and Rubber-covered hose. This method of construction gives a light, weather-proof hose which needs no drying-out and which is well adapted to the requirements of small municipal fire-fighting and street-cleaning departments. On the whole, however, Woven Jacketed hose for use outside of fire-fighting is 60 Rubber in Industry more costly than the average traffic will bear. This doubtless accounts for the fact that its use today is largely confined to fields as just mentioned. (4) Combinations of Wrapped Duck and Braided or Wrapped Duck and Woven Jacketed constructions although not of recent origin in the history of hose development are nevertheless, today receiving more at- tention than formerly. Probably this is due to the fact that these types furnish hose of unusual ruggedness adaptable for the especially hard usage met in many industrial fields. Combination constructions have the added advantage of greater strength and also greater flexibility than is possible of attainment where Wrapped Duck alone . is used. The weave or braid providing extra protection against ply separation, snags or cuts, and with the extra advantages of an absolutely smooth tube, recommends combination construction hose over other types for many severe applications. This type of hose is particularly adaptable for air drill, boiler Avashout and steam service although it may, however, be recommended for any service where the expense involved would be warranted. The most widely used combination, i.e., Wrapped Duck and Braided, is made by first producing an or- dinary Wrapped Duck hose of two or more plies, covering with compound and then braiding over this one heavy ply of cotton reinforcement. The usual rubber cover is then applied and the hose vulcanized in the same manner as described under Wrapped Duck construction. Wrapped Duck and Woven combination is made in the same manner except in place of the Braided covering be- ing applied over the Wrapped Duck type, a Woven 61 Rubber in Industry Cotton Jacket is employed. This type is, however, very little used. The Uses of Hose. To the lay public, hose is not often thought of in connection with uses outside the garden, lawn, or greenhouse. Yet the application of hose to industrial service is so broad in its scope that in this brief work it would not be practical to attempt more than a mere hint at the places where this important rubber article may be found playing an important part. Suffice it to mention that hose forms one indispensable item of equipment in every plant where water, steam, gas, oil, or other fluids are conveyed from point to point; and, as we have hinted at in previous paragraphs, the conditions surrounding each application sometimes determine the type of construction employed and al- ways the quality and makeup of the one used. The B. F. Goodrich Company has developed over forty dif- ferent purpose constructions in order that our product may be better fitted to meet all practical needs of con- sumers. To give an idea of what these requirements are we need but mention that Acid Hose, Air Brake Hose, Air Drill Hose, Boiler Washout Hose, Chemical Hose, Cider and Vinegar Hose, Coke Hose, Deck Hose, Drillers' Hose, Fire Hose, Mill Hose, Garden Hose, Gasoline Hose, Hydraulic Hose, Oil Hose, Gas Hose, Pneumatic Hose, Radiator Hose, Sand Blast Hose, Spray Hose, Squirt Hose, Steam Hose, Suction Hose, Tender Hose, Vacuum Hose, Varnish Hose, Water Hose, and many others, all require a construction peculiar to the service rendered. Oftentimes mills and other users will be found pur- chasing a grade or type and using it in a service for 62 Rubber in Industry which it was not originally intended. Naturally, these consumers will not be found receiving the value to which they are entitled or which they might get by employing the right hose in the right place. To many "Rubber hose is rubber hose," and the returns which they receive from a particular piece in one service they take to be an interpretation of the quality of the product which may have failed. All failures in service, however, can- not be taken as indicative of poor quality in hose con- struction for as will readily be seen our highest grade of Water hose — White Anchor — which in many cases has been found in use for from fifteen to twenty years under normal conditions would give out in a very few weeks if used for conveying acids or oils. It is, there- fore, our mission and our endeavor to educate the buyer in the right use of those brands which we as specialists have particularly developed for specific pur- poses. While it is true that there are a multitude of brands, each brand in the Goodrich line indicates a construction and moreover each represents a distinct development different from all others. CHAPTER THREE Molded and Lathe-Cut Rubber Qoods DEFINITION. In its all-inclusive sense, the term, Molded Goods would embrace all articles receiving their shape and permanence of form in molds on hydraul- ically or even hand-operated vulcanizing presses. Full molded pneumatic tires, solid tires, hard rubber items of many descriptions, boots and shoes of the Hi-press type, various sundry items such as bulbs, balls, water bottles, etc., are, however, constructed after this general method and yet are not embraced within the category of Molded Goods in the true factory sense. The term is indeed hard to define for it embraces a miscellany of soft rub- ber articles outside the Sundries line which are, never- theless, of a sundry nature, i.e. for many purposes and of many shapes. All, however, are manufactured by molding or curing under pressure in so-called cavity molds hence the term Molded Goods. The widest diversity is represented in the compounds used for the manufacture of this line ranging from the finest quality of raw rubber as a base to the cheapest reclaimed stock and from the softest of gums to com- pounds as hard as iron as illustrated by teething rings on the one hand and heat-resisting valve rings on the other. Naturally the stocks are prepared by many different methods depending upon the "flowing" proper- ties of the compound and shape of the mold. This 64 Rubber in Industry feature we will, however, treat later on. But closely related to the molded goods line in both manufacture and application are those items some of which are molded and some not, which because they receive their shape after being cured, by sharp knives either hand- operated or on lathes are designated by the general term Lathe-Cut Goods. Historical. If we are to believe the historian, molded rubber articles were first made by the South American aborigine who used clay for his mold material, some- times smearing the latex over the exterior and some- times confining it within. Footwear, bulbs, balls, and toys were made in this manner but in each case the mold was afterward broken to procure the finished article in perfect shape. It is true, however, that Thomas Hancock of London, England, was the first to begin the manufacture of rubber goods on a practical basis and it is probably true that the first Molded articles were also manufactured by him. At any rate his were the first brought to public attention receiving as early as 1820 quite general fame in Great Britain. Like all other rubber goods, however, these first Molded articles had very little commercial value and until after the dis- covery of vulcanization could not be manufactured into items of permanent shape and form which would remain free from stickiness. But immediately this basic dis- covery was made the use of Molded rubber articles be- gan to expand apace, a movement which has continued to grow even to the present day. Shortly after his discovery Charles Goodyear granted licenses to various manufactories in this country for the application of his principle to the manufacture of 65 Rubber in Industry Molded rubber articles and about the same time, that is, 1846, Thomas Hancock took out a patent in Eng- land for improvements in the manufacture and treating of articles made of caoutchouc, either alone or in com- bination with other substances and for the means used and employed in their fabrication. This, reduced to simple English, translates; for the manufacture of compounded rubber articles vulcanized in cavity molds. Beyond this brief sketch, a history of the Molded Goods line would be of little value in this work if indeed it would be possible to compile such data. Suffice it to mention that the history of the Molded Rubber Goods line is yet in its infancy, and although thousands of articles are today manufactured by this method it can be said upon competent authority that the possibilities are not as yet even known. In the United States we have reached our present status through a slow period of development beginning with about the year 1846; new uses and adaptations being discovered, one might say, almost daily. How many thousands of articles are today manufactured by the Molded process is, however, probably not known for many uses have been born, lived their life and died; while others have been found which are of lasting benefit. The character of the output of any large Molded Goods factory we can say is therefore constantly changing from month to month, as new items are added and old ones dropped ; but today in the Goodrich factory more than 27,000 different articles are made by means of forcing rubber into cavity molds and there holding it under pressure for the duration of the cure. Doubtless even as this is being written new items are being added. 66 Rubber in Industry Characteristics of Molded and Lathe-Cut Rub- ber Goods. As previously mentioned Molded and Lathe-Cut Goods may be soft and pliable or tough and rigid, almost like iron. They may also be of almost any shape or size and constructed either wholly or in part from rubber compound. They may sell alone as items of commerce (witness the heel) or, as is usually the case form an accessory part to some machine or appliance made and sold by others. All, however, have in common one characteristic. By this we mean that they represent the manufacture of rubber goods in its most elemental form and the steps in construction be the item a tackbumper or deckle strap are substantially the same from the milling of the compound to the cleaning of the finished product. Regardless, however, of the character of the article, the construction of the molds themselves is a feature of vital importance and one which has an important bearing not only on the successful carrying on of the processes but upon the service which the article itself will later give. In fact so important is a proper con- struction of mold equipment considered in the manu- facture of a Molded Goods Line that we cannot trust the average machine shop with the making of such equipment. We therefore maintain in our own plant a department where the work of Mold building may be carefully supervised by men thoroughly skilled in this line of mechanical work and who are familiar with the characteristics of rubber and the requirements of rub- ber mold work. In this connection we may mention further that The Goodrich Company has developed the art of Mold making to its highest degree of perfection having skilled mechanics and die-cutters who are capable 67 Rubber in Industry of handling the most intricate of patterns. Unlike many manufacturers of such a line we believe that a high class article cannot be made in a mold not built accord- ing to the most scientific and accurate specifications and from a grade of material particularly suited to the purpose. The process of vulcanizing Molded Goods is one of vital importance and must be the result of proper temperature kept steady for an exact length of time. The success of this depends in large measure upon the proper construction of the mold and is a point in manu- facture where the experience and reliability of the mold maker has its effect in producing a first grade article. The Manufacture of Molded and Lathe-Cut Goods. Any description of the manufacture of Molded and Lathe-Gut Goods properly begins in the washing room with the preparation of the basic raw product — rubber — and to be entirely complete such a story should continue on through a description of the compounding and milling together of the rubber and other ingredients which are used. Since, however, these materials prepar- ation steps have been so often described and since for Molded Goods they are virtually the same as for other classes of rubber manufacture we will commence our description with the shaping of the stock preparatory to vulcanization. This step we may mention compares, for instance, to the building-up process in the manu- facture of hose, belting, or tires. Stocks for Molded Goods are not usually calendered being received in the building department in batch form and here treated, as may be imagined, in various ways depending upon the nature of the article to be manufactured. If for a rubber roll or other item whose length is several times 68 Rubber in Industry its breadth and depth, the ordinary tubing machine may be employed to considerable advantage. In such a case the stock being fed into a hopper and from here passed through heated dies as described in previous chapters will issue in approximate form. If the article is to be a heel or a valve disc the stock may be also run into lengths on the tubing machine and afterwards cut mechanically, or even by hand into pieces roughly re- sembling the shape of the finished article. Again the stock may be calendered on a small mill to the required thickness and pieces punched from the resulting slab by dies either hand or mechanically operated. From here on, however, the process in Molded Goods manufacture takes a more uniform course in that the raw gum whatever the nature of the finished article, must be made to conform in weight exactly to that of the completed unit. This step, as we will show, is of the utmost importance in maintaining a uniformity of product. In other words it will be recognized that economical factory practice does not permit of exactness in calendering or cutting such stocks and it should also be recognized that unless there is this exactness as to the quantity of material used, a considerable spoilage would result. Many articles when cured, would be undersize due to the fact that an insufficient quantity of material was used and then again, an excessive "overflow" would result from the use of too great a quantity. Therefore, in nearly every instance each piece before it is allowed to proceed to the next step in the process is weighed and trimmed that exactness may be secured. While it may seem that such a procedure must necessarily call for a tremendous amount of hand labor it has been found to be thoroughly practical 69 Rubber in Industry from an economy standpoint. Moreover when com- pared to the intricate steps which other rubber goods must pass through in the building-up, this weighing and checking is after all a rather simple procedure. Having been trimmed to exact proportions, the roughly shaped pieces of raw gum are transported to the vulcanizing department and distributed throughout the room convenient to the presses upon which they are to be cured. Let us imagine for a moment that we are in a huge bakery where battery after battery of ovens each manned by an expert baker are employed in turning out an endless quantity of cakes, cookies, and buns. Then we will get some idea of the vulcanizing department of the Molded Rubber Goods shop. The presses as these ovens are known are in reality steam- operated stoves composed of a base, head piece, two hollow heated jaws, a hydraulic ram, piping, etc. In front of each press is a narrow bench upon which the workman may arrange his material and suitable valves for controlling the heat and pressure of the jaws. Gages are provided which enable the press-man to exactly con- trol these two elements for each class of stock being cured. Suitable tanks of cold water are provided be- tween each battery in case it is required that the molds be cooled before the articles may be removed. The molds themselves which are usually of two parts though sometimes of three or more, are spread open on the table directly in front of the press after having been first heated for a few moments. If metal parts are to form a part of the article these are next arranged on suitable pegs or in depressions in one half of the mold. The pieces of raw gum are then placed within the cavities, the mold put together and sli' 1 into place be- 70 Rubber in Industry tween the press jaws where hydraulic pressure is brought to bear by the ram, squeezing the stock into every crevice and corner of the mold cavity. Here it is held under an enormous pressure ranging from 15 to 680 thousand pounds according to the article under con- struction, until that change in the rubber has taken place which turns it from a sticky, useless mass into a tough, resilient article. By way of further explanation we may now mention that the duration of this cure varies from five minutes to two hours or more according to tem- perature, characteristics of the compound, and size of article, all factors being worked out to a certainty in our laboratories during the experimental stage. The impression prevails quite generally that Molded Rubber articles are made from molten or liquid material as are casting of iron, copper, brass, etc. If therefore, any of our readers have heretofore entertained this im- pression the preceding description although not by any means complete in detail; should serve to correct this perfectly natural error. Vulcanized articles of this class, however, upon being removed from the mold do somewhat roughly resemble an unfinished casting in that there is always present a rind or fin occasioned by the overflow of material through the joints where the mold pieces come together. The mold by the way, may con- tain one cavity or several dozen depending upon size of article, etc. The rinds on rubber goods as on castings must of course, in turn be removed before the article can be said to be complete. This is done in a variety of ways depending upon the size, shape, and general character of the item and the quantities in which it is manufac- tured. Imagination, however, should assist our readers 71 Rubber in Industry in coming to the conclusion that where very small quantities of special items are manufactured the trimming must ordinarily be done by hand, whereas where quantities are large and production constant, machinery can be designed and used in this operation. Such at least is the case and regardless of the shape of the article or its size, in every well appointed factory where Molded Goods are turned out in quantities, will be found a variety of specially designed machinery em- ployed in the trimming off of the rind or superfluous rubber from the cured product. This description so far will also apply to the manu- facture of lathe-cut goods. Some coming under this last category are however not molded, but on the con- trary are wrapped with wet muslin tape and cured in open steam heaters as is wrapped duck hose. Further, the production of "lathe-cut" goods goes one step be- yond the trimming off of the rind in that their shape and finish are imparted by turning or cutting upon lathes. Many such items are cured in lengths being afterward cut to small dimensions such as Mason's jar rings and printers' feed rollers, while others such as typewriter platens are merely turned down to proper dimensions. Knowledge of rubber compounding gained through many years of experience and use of superior materials, together with facilities for the manufacture of precise mold equipment have brought us to the point where we are today enjoying a large percentage of the great volume in Molded Goods purchased throughout this country. This figure has been estimated at ten million dollars annually which if one stops to consider the multitude of special requirements including rubber parts 72 Rubber in Industry of typewriters, pumps, printing machinery, together with soles, heels, billiard cushions, etc., will not seem an exaggerated figure. On the contrary this will prob- ably appear as a rather small price to pay for the thou- sands upon thousands of rubber necessities without which a great deal of our machinery would literally be of no value. The Use of Molded Goods. The fact that a great percentage of the items constructed by the molded process are special in nature makes it difficult in a work of this character to give even the remotest idea of the extensiveness of such a line. It is in the truest sense a made-to-order line, which statement is borne out by the fact that nearly 50 per cent of all Molded Goods business consists of special items; which is to say of items not universally used but which comprise accessory parts to machinery, etc. Our chemists are almost con- tinually experimenting with compounds to take care of demands for new molded rubber articles and our pro- duction men are co-operating with them in figuring out ways and means for manufacturing such articles at a cost which will not be prohibitive. Every day problems of this nature are referred to us by geniuses or would be geniuses seeking new applications in the field of rubber. It would be, however, an impossibility in the brief chapter which we have allotted to this subject to give anything more than the faintest idea of the multitude of uses for molded rubber goods. As mentioned pre- viously, in the Goodrich Factory alone over twenty- seven thousand articles are embraced within this cate- gory and this does not include those which fall under the classification of lathe-cut articles. Printing ma- 73 Rubber in Industry chinery, paper making machinery, plumbing, type- writers, automobiles, motors, generators, type setting machinery, paper box machinery, bean sorting ma- chinery, and in fact, in every walk of present day in- dustrial life there are hundreds upon hundreds of molded rubber articles used alone or as supplementary to mechanical devices. Since therefore, we cannot ex- plain the use of the whole list it will have to suffice that we give an idea of the requirements of such articles by an explanation of a few of the more prominent items. (1) A pump is the heart of a circulating system and its valves perform the same function as the valves of the human heart. An indispensable part therefore, of every pump whether it serves to force drinking water into city mains or ammonia through an ice plant is its valves. The general type is a round rubber disc with a hole in the center and in common types of pumps there are two sets. These are the suction and discharge, controlling the direction of the fluids flow through the piping. The "suction" valves cover the suction ports lifting to permit the fluid to rise from the reservoir into the pump cylinder during the suction stroke and closing to prevent its return during the discharge stroke of the piston. The "discharge" valves perform the same serv- ice; permitting the piston to force fluid out of the cylinder into the discharge pipe or service line and preventing it from returning during the following stroke. The action of pump valves is automatic, be- ing controlled entirely by impulses set up by the pump piston and the positiveness of their action is provided for by spiral springs which react against the impulses. The ports or holes over which the valves fit are usually provided with grids subdividing each port into 74 Rubber in Industry several small triangular openings and serving as an anchorage for the bolt which hold the valve and valve spring in position. The velocity of the flow of the fluid and the gritty content of most liquids gradually cut away these metal ports causing the valve seats to be- come somewhat uneven. Even slight imperfections be- tween valve and seat surfaces will cause leakage; which progressively and greatly reduces pumping efficiency unless a valve material is used that will in some measure conform itself to seat irregularities. For this reason metal valves are not employed when temperature and pressure will permit the use of some flexible material. Rubber, balata, leather and other fibrous substances are therefore used in the manufacture of pump valves; but the distinction of rubber as the most enduring of all elastic substances makes it the standard valve material. Pressures over 350 pounds per sq. in. and temperatures greater than 250 degrees F., however, preclude the use of any but metal valves. The B. F. Goodrich Company manufactures and offers to the trade rubber pump valves in thirty odd grades, compounded and constructed to handle liquids under all temperatures, pressures, and degrees of purity, within the allowable limits. There are soft pliable valves for light pressure cold water service and bone hard valves for hot water and high pressure pumps. These vary in size from a diameter of less than 2 inches by | inch in thickness to more than 2 feet in diameter by 3 inches in thickness. The smallest are accessory to the small high pressure lubricating pumps while the largest are used in mine and bilge guard pumps. In addition giant high duty pumps are equipped with several relatively small valves rather than a few large ones on account of 75 Rubber in Industry the efficiency of such practice, the most popular size being about a 4 inch diameter. A reminder that pumping equipment is an essential part of every plant and almost every industrial project will suffice to disclose the vast possibilities of this avenue for the distribution of molded rubber products. While it is true that centrifugal or turbine pumps are replacing the piston type in many places and that these do not require valves it is also just as true that there is a well defined field of application for the piston pump which cannot be occupied by the "invader." The in- dustrial use of pumps is yet in its infancy and the out- put of the larger manufacturers shows increases in pro- duction of piston pumps from year to year, calling for ever increasing quantities of rubber valve discs. By way of information we may mention that this company manufactures and markets more valve discs than any other rubber company. Since the earliest days of the mechanical era, valves have been employed to regulate and control the flow of fluids. The first form was, no doubt, the wooden gate used to close openings in dams and ditches. Then came the spigot to shut off the flow of wine when the decanter was filled; and now we have gate valves, safety valves, cocks, etc. The gate valve is the most widely used and is the type in which rubber plays an important part as the closure member. These are flat circular pieces with round or oval holes through the center; and are mounted in the valve on the lower end of a screw; the upper end of which is usually equipped with a hand wheel. The action of the screw causes the gate to move away from the seat permitting the steam, water, or other fluids, to pass, or inversely, to press against the 76 Rubber in Industry port closing it tightly and effectively shutting off the flow. The rubber disc provides against irregularities in the edge of the port flanges, caused through the pitting of the metal when acids or other injurious elements are contained in the liquid which passes through the pipes. There are two standard disc valve types, Jenkins and Crane, both of which we manufacture in all sizes. Re- quirements in valve service vary with the pressure, temperature, and nature of fluids, but we have found that our standardized disc as made in two grades only, for Low duty and High duty service, meets all require- ments so effectively that the reputation of Goodrich valve discs remains unchallenged. (2) The rapid rise in the art of metal stamping has created a considerable demand for molded rubber spring bumpers for use in connection with stamping presses, and this demand is increasing. Sheet steel, aluminum, brass, tin, copper, or any other metal which may be drawn is today being stamped into a multitude of shapes and sizes for many purposes by means of dies. One-half of the die is generally attached to the bed of the press while the other is fastened to the plunger. In certain kinds of stamping work, particularly that known as "drawing" with combination dies, rubber pieces are usually found at the bottom die for the purpose of exerting a constant back pressure and thereby keeping the metal tight in the holding ring. Thus wrinkling is prevented during the drawing process and when the punch is released these pieces of rubber also serve to force the holding ring back into its normal position at the same time ejecting the stamped piece from the die. The diameter and length of the rubber spring is of 77 Rubber in Industry course, governed by the thickness of the metal to be worked and the depth of the stroke of the press. Other rubber spring bumpers which perform the same general service in various ways are also almost number- less; as for instance, flexible coupling rubber buffers are used to correct slight differences in alignment and to absorb a portion of the starting shock where motors are coupled directly to the shafting of the driven ma- chines. Track bumpers in railroad yards or where small cars are employed around mines are also employed to prevent the moving car from striking at the ends of the tracks with destructive force. Spring board cushions, steam shovel bumpers, mailing table pads, grindstone collars, channeling machine springs and hammer cushions are a few of the thousands and one other uses to which this type of molded rubber may be put. The stock used in any service required of spring rubber must possess a high degree of "come-back" quality and must be able to withstand continuous and frequent compression without the loss of life. A rubber band, as we well know being stretched beyond its limits of elasticity breaks. The same thing is true when a solid piece of the same material is compressed beyond the limits of its elasticity; except that the break may occur within where it will not at first be evident. Know- ing this, the difficulties met in compounding spring rub- ber so that the "recovery" feature is always present will be obvious; and when we mention that the demand made upon us for this product is growing with each passing day it will be seen that our chemists and fac- tory men have perfected a spring rubber which will give service. (3) The tremendous increase in the demand for 78 Rubber in Industry sanitary plumbing has resulted in a marked growth in the manufaeture of plumbers' vitreous, enameled ware and brass goods, and as is natural an increasingly large demand for the various rubber parts which are acces- sory to such fixtures. Although these rubber articles are usually small and somewhat obscure by virtue of their being hidden, the aggregate volume is exceedingly large. Plumbers' rubber articles and their application is indeed too big a subject to be dealt with in its entirety in other than a volume written on this phase of rubber manufacture alone. Accordingly, we will mention only the most common items manufactured for this market merely to convey the impression of the indispensableness of rubber to the comfort and safety of mankind in all walks of life and the role molded items play. These are Fuller Balls, Bibb Washers, Tank Bulbs, Siphon Packers, Elbows, Basin and Sink Stoppers, Force Cups, Tack Bumpers, and various connecting parts. Fuller Balls and Bibb Washers as employed in the two principal types of faucets are. however, items with which we come in daily contact and accordingly it will perhaps be well for us to at least define the use of these two. The Fuller Ball is a part of the valve which works on the crank principle closing and opening by forcing the ball against the seat of the valve. This type is employed in water faucets where as soon as the hand is removed from the lever the flow of water ceases. Bibb Washers may be compared to Valve discs, pre- viously described, being simply flat circular pieces which compress against the valve seat as the faucet is screwed down closing the opening and stopping the flow. Al- though as previously intimated, rubber parts are used profusely throughout all modern plumbing work the 79 Rubber in Industry descriptions of the application of these two items will serve to illuminate the wide diversity of the uses of molded rubber goods and at the same time give an idea as to the compounding requirements which must be met. (4) The development of the molded rubber cushion has without question more than any other agency been responsible for the present day universal popularity of the game Billiards. This is evidenced by the fact that this game was introduced into the court of Charles IX in France in 1571 and yet attained no great popularity until Michael Phelan introduced in 1854 a rubber cushion possessing durability and elasticity. Billiard cushions were among the first items of manufacture by The B. F. Goodrich Company and during this fifty-year period of development the Goodrich has been recognized the world over as having played an important part in popularizing the American Cushion. This statement is exemplified, we claim, by the fact that today Goodrich cushions are more popular and more widely used than ever. Although the cushion itself is somewhat obscured by being built into the table and marketed through channels not well known of to the general public yet there is a tremendous volume in this division of the molded goods line. We have told throughout the preceding paragraphs of this chapter why in the usual run of the molded mechan- ical rubber items a variety of constructions and grades are demanded to meet different conditions of service. This is only slightly less true of the Billiard Cushion business, due to the faci that different table builders and purchasers have different ideas as to what con- stitutes the best type of cushion. The skilled match 80 Rubber in Industry player demands accuracy, uniformity and an exacting degree of speed, while the moderately skilled amateur although appreciating accuracy wants more speed than the professional. To meet these demands we produce two grades made up in different styles. These are namely, the all-rubber, the cloth backed a cushion with a layer of- fabric vulcan- ized on the lower side and, the cloth and wire insert types. Although we feel that the last does not possess uniformity of structure, accuracy and length of life found present in the all-rubber or cloth insert types nevertheless, we produce wire insert cushions for the user who believes wire necessary in maintaining proper speed. It is not our intent to make a catalog of this work nor that the reader should be expected to become familiar with grades and types in their various applications from this necessarily meagre description. We cite these facts concerning demands merely for the purpose of familiar- izing our readers with the necessity for a close study of all sorts of conditions on the part of the manufacture of a general line of molded goods. We may mention however that the Billiard Cushion is one of those items receiving its approximate shape by the employment of the standard tubing or "spewing" machine. The holes for the wire insert type are made simultaneously with the shaping of the stock through the use of mandrels built into the die. To produce the best wire insert cushion only the best highly tempered steel wire may be used and to effect proper adhesion of metal to rubber a chemical treatment to the former must be given which is only another illustration of the problems met and overcome by the successful maker of molded goods. 81 Rubber in Industry • — — — — — (5) So far in our illustrative description of the diversity of uses to which molded rubber goods are applied we have confined ourselves to those items which are supplementary to other devices. In order, therefore, to illustrate the other extreme, i.e. the domestic use of molded rubber goods we will take the Sole and Heel as our next topic for discussion. Just as surely as the world's supply of good leather from which to manufacture serviceable soles and heels is diminish- ing just so surely must shoe makers in time be forced to seek a leather substitute. What better material could there be than properly compounded fibre made with a base of rubber as the binder? Already the use of rubber heels has reached enormous proportions as evidenced by the fact that over seventy-five thousand pairs including the entire O'Sullivan production are daily turned out in the molded goods department of The B. F. Goodrich factory. Fibre soles, although today not universally adopted by shoe manufacturers, will without question in time come to be the logical sub- stitute as the shortage of good sole leather becomes more and more acute as it is surely bound to do in the face of the increasing demands for leather in other fields. The Goodrich Textan will maintain its place in the forefront when fibre soles become supreme; a place which this brand even now enjoys in the limited suc- cess to which fibre soles have so far attained. We have attempted in the few brief pages preceding to convey an accurate impression of the problems in com- pounding and manufacture which have been met and overcome by this company in its enormous output of molded goods for every field of usefulness. At the same time we have endeavored to amplify the assertion 82 Rubber in Industry that the use of molded goods is still in its infancy. If we have succeeded, we will have prompted the coming generation to seek other and more practical fields for the sale of molded goods and through the use of their facul- ties they will doubtless henceforth discover more uses for rubber than is today even dreamed of. This chapter then will not have been written in vain. 83 CHAPTER FOUR Packings INTRODUCTION. Packings are primarily used to correct mechanical irregularities in the surfaces of re- movable parts of steam chests, pump cylinders and similar devices wherein steam, water or other fluids and gases are meant to be handled with as little leakage as possible. Secondarily, they are used to stuff, or more properly, to pack the glands around pistons or rods to prevent the escape of the fluid under pressure through the sliding joint between the moving piston rod and the stationary part. Theoretically a cylinder or chest could be made "tight" by simply bolting together the finished surfaces of the two metal parts involved. It would be supposed that machined surfaces would form a close enough contact to effectually retain the fluid. Experi- ence, however, has shown that such a joint though pos- sible is impracticable in that the metal will soon rust and a slight particle of foreign matter will cause the joint to leak within a short time. Other than the possibility of leaking, the joint could not be easily separated since rust would form a porous and tenacious binder. To separate a joint after rust has completed its destructive work requires a force which is liable to mar the parts and render them useless for further service. On account of its uselessness, as soon as trouble developed at the unions and flanges, it seemed for a time that the steam engine, one of man's most important inventions, was to be almost valueless. The early en- 84 Rubber in Industry gineers, however, were not content to throw the steam engine on the "scrap heap" as an interesting but worth- less experiment and set to work to devise a joint which could be broken and reassembled with ease. Packing eventually was the outcome. First, we find leather be- ing used and for a time it seemed as if this material would remain supreme in this field unchallenged. Leath- er was easily cut to the shape required; it would com- press readily into the irregularities of the metal parts and in addition, possessed sufficient tensile strength to withstand, for a time, ordinary steam pressure. The first fault which worried the engineer in the use of leather was the fact that it could not be rendered impervious to the action of the fluid within the engine. Once the exposed edge on the inside of the cylinder became soaked the capillarity of the leather, due to its fibrous structure, carried the liquid throughout the pack- ing and it quickly rotted. Again man's ingenuity was called upon to come to the rescue of his inventions. About this time, 1850, rubber was being put forward as a "cure-all" for all waterproofing troubles and it was but logical for this material to be tried out as a sub- stitute for leather packing. It worked and soon all engines were provided with rubber packings which saved steam, diminished jar and facilitated the opera- tion of the machine. Packing cut from sheets of rub- ber was found capable of withstanding greater pres- sures with greater assurance against blow-outs. Again encouragement returned and the further development of the steam engine began. At first the steam engine was used only to operate mine pumps or to do such other work as formerly had been done by animal strength and therefore steam pressures only slightly greater than 85 Rubber in Industry i ■ — — — — ■ atmospheric pressure had satisfied all requirements. But the possibilities of such tremendous tireless energy encouraged the development of machinery of constantly increasing capacities and power requirements. In keep- ing apace with the demand for more and more power, dimensions of cylinders and other parts became enor- mous. Thus the engine occupied too much space and soon reached a limit beyond which it was not practical to go. Since the area of pistons could not be further increased the only alternative, after grouping engines together, was to increase steam pressure. Thus a small engine could be made to do the work of several much larger ones and High Pressure Practice had its beginning. The end we cannot see. Temperature of steam varies with the pressure and engines are operated by the expansive force of heat rather than by the blowing effect of steam. Although the temperature of saturated steam, i.e., temperature due at 150 lbs. gauge pressure is 358 degrees F. or 118 degrees hotter than steam at 10 lbs. gauge pressure it is often found expedient to employ a superheater and thus again raise the temperature, in some instances, 100 degrees. It is then called superheated steam. The ef- fect of steam at 458 degrees F. (150 lbs. gauge and 100 degrees superheat) was more than sufficient to destroy almost any packing material known at the time of the introduction of superheated steam. For several years rubber manufacturers had been re- questing the entire mechanical profession to submit their packing difficulties for solution and various inter- esting compounds had been worked out to overcome certain difficulties. Gasket packings had been devel- oped to withstand the action of acids which had pre- 86 Rubber in Industry viously been considered active rubber solvents. Oil could be pumped using rubber gaskets and packing about the pump cylinders. In fact rubber men were somewhat "chesty" in their statement, "we can make a rubber compound to satisfy any particular packing requirement." Steam engineers at their wits' end ac- cordingly challenged these rubber chemists to make good their statement. Not instantly but exceedingly well did our compounding experts evolve a combina- tion of ingredients to produce a packing capable of withstanding any degree of superheated steam which has so far been found necessary to use. From this satisfactory solution Goodrich Packing has made step by step of progress to meet the exacting conditions of various lines of steam enclosures. The Manufacture of Packing. Packings are neces- sarily furnished in many grades and forms to meet the various requirements of this accessory essential to the conveying of steam, water, oil, and in fact, all gases and fluids. It would, however, be impracticable in a work of this nature to even attempt a detailed des- cription of the steps involved in the construction of all types and grades and it must, therefore, suffice that we confine the following discussions to fundamentals which concern the construction of all types alike. For the ! ake of convenience in expression we will classify all packing under three general heads, viz., Sheet Packing, Square and Round Packing and Com- pressed Packing. Each of these is made in several sub- types and grades and as may be supposed each general type must be constructed by methods peculiar to its form and nature, special machinery being employed 87 Rubber in Industry wherever justified by the volume manufactured. In the following paragraphs we will treat the manufacturing steps of each general division in the order named, be- ginning our description directly after the milling and calendering process since these preliminary steps have been so well described in other places. (1) Sheet Packing is constructed of layers of com- pounded stock built up ply upon ply by a calendering process and may be made either of rubber compound alone or of rubber with cloth insert known as G. I., a cloth backing either one or both sides known as C. 0. S. and G. B. S. or with a brass wire insert known as B. W. I. In these reinforced types the layer or layers of insertion or backing are placed in their proper position during the building up process the whole being subsequently vulcanized into a compact unit between steel plates on a flat bed hydraulic press. This gives the surface a smooth, or as it is termed in trade parlance, a plate finish. But, if a smooth surface is not desired what is known as a fabric finish is given by placing, above and below, between the metal plates and the uncured stock pieces of wet muslin or duck from which the impression of warp and weave is secured by the pressure of the ram during the cure. Little else need here be told con- cerning the manufacture of sheet packing; indeed there is little else to tell. The vulcanized product being im- mediately ready for the market is merely put up in rolls in the size and form in which it comes from the press. The reader, however, must not come to the con- clusion that because the manufacture of sheet packing is such a comparatively simple process that skill is not required; for a knowledge of conditions to be met in service, a knowledge of rubber chemistry and compound- 88 Rubber in Industry ing and an ability to apply this intimate knowledge of rubber in the compounding and manufacturing steps makes all the difference in the world between a success- ful and a poor packing. (2) The classification, Square and Round packings includes not only those which are perfectly square or circular, but rectangular and oval shapes as well and these may be made either of solid construction or with a hollow center. In the former they are made either entirely of rubberized fabric or with a core of compound reinforced with windings of rubber impregnated fabric. The square duck solid construction variety is made by building up a huge slab of rubberized fabric by impos- ing one ply on another until the desired thickness has been secured, vulcanizing into a solid unit and after- ward cutting by special machinery to widths desired. Circular packing whether it be either of the hollow center or the rubber core variety, is constructed much after the manner of wrapped duck hose in that the plies of fabric are secured by a process of wrapping either around a mandrel as for the hollow type or around the core as for the rubber center type. This construc- tion, as may be imagined, is wound with wet fabric and cured in heaters much the same as is wrapped duck hose. A square, rounded corner packing is also frequently made after this mode of manufacture. (3) Compressed Packing comprises that type com- posed of a fibrous ingredient held together by a binder of rubber and is built ply upon ply under an enormously high pressure. Goodrich Compressed Packing known as "Superheat" is composed chiefly of long fibre asbestos plus the rubber binder and other ingredients which are necessary. We secure directly from the mines the 89 Rubber in Industry Feldspar ore from which asbestos fibre is made mil ing and refining it in our own plant in order that we may insure that the original length of fibre is retained in the finished product. This we mix with the other ingred- ients required and on a huge mill build up sheets layer after layer to the thickness desired, afterward cutting the sheet from the rolls in which form it is vulcanized on flat bed hydraulic presses. Many substitutes for "Superheat" are offered to the trade which are made with various other fibres as the base, but Superheat Sheet Packing is essentially a Goodrich contribution and unequaled as a packing for high pressure and superheated steam. On account of its nature and the method of manufacture employed we do not furnish "Superheat" in rolls but rather in sheets 50x50, 50x150, and 50x75 inches. (4) Although we have indicated in a previous pa a- graph that packing is generally classified under three groups there is yet another type which we have not mentioned. This is that known as "Spiral" packing and is generally classified separately although but a variation of the square and round construe ions. The same general steps in manufacturing are followed as described in the construction of square and round pack- ing although "spiral" is never vulcanized in slab form. On the contrary, both shapes are built to their final dimensions and by machinery wound in the form of helix over iron poles or mandrels, wrapped with wet muslin tape and cured in this manner in horizontal heaters coming from the process in the form of long spiral springs which are afterward cut to convenient lengths and boxed for shipment. There is, however, "Lubricated Spiral" packing which is procured by im- 90 Rubber in Industry mersing the cured spirals in a bath of hot oil, subsequent- ly graphiting in an ordinary rotating tumbler. Characteristics of Packing. We have mentioned in the introduction to this chapter that packing is made for a great variety of uses, that is, for securing against leakage the glands and unions of high and low pressure steam engines and lines, hot and cold water pumps, ammonia compressor pumps and piping and for pumps and piping in breweries, distilleries, chemical plants, etc., where unusual conditions of service are to be met. It therefore necessarily follows that the characteristics of rubber packing must vary in order to meet these dif- ferent conditions of service. Such, in truth, is the case and we find that a particular packing which serves the purpose well in one installation will be wholly unsuit- able for the work required in another. It is not our purpose to go at lengths into detail concerning the characteristics required under all service conditions. The reader, however, will perhaps be able to gain a more ac- curate impression of what is required from the manufac- turer who pretends to furnish this necessary product to meet all sorts of industrial uses if we cite a few examples of service requirements mentioning the types of packing which are best suited to each. In many instances, however, special requirements are more theoretical than actual by which we mean that the whims and tastes of engineers often have an influence upon the type of packing which is used. Some oil well men, for example, believe that a wire insert packing is positively essential in their line of business whereas, as a matter of fact any good all rubber sheet packing compounded to resist the action of oi 1 would serve the 91 Rubber in Industry purpose as well if not better. In the main Sheet Pack- ings may be used for general purposes either on hot or cold water, compressed air, low pressure steam, am- monia compressors or chemical lines and will be found serviceable in any climate and free from hardening or cracking. Moreover sheet packing if lubricated or in- stalled between lubricated joints may be used over and over again many times. "Superheat" packing is of course especially adapt- able to high pressure lines and where superheated steam is to be conveyed or used. The very nature of the compound renders it heat resisting to a high degree making possible the efficient and economical operation of any engine where superheated steam is required. Superheat packing is, in fact, so scientifically com- pounded and the mechanical devices employed in its manufacture and cure are so well perfected that uni- formity of thickness is possible and ply separation un- known. This packing may also be used over and over again. Thus it is economical as well as safe. The principal field for the application of Square Duck Packing commonly known as Hydraulic Packing is the plunger end of hot and cold water piston pumps. In hot water service such as boiler feed pumps it is ad- visable to use a grade constructed of fine duck with a high quality friction. This will pay from the standpoint of less susceptibility to swelling in addition to the gen- eral advantage gained through the longer wearing properties obtained by the use of high grade materials, since any marked degree of swelling tends to shorten the stroke of the plunger which in turn reduces the capacity of the pump. Coarse ducks especially in com- bination with cheaper friction can be used to advantage 92 Rubber in Industry only for clear water pumping and where muddy or gritty water is encountered the fine duck will show far greater efficiency. Spiral Packing is used in the same class of service as Square Duck, i.e., for packing glands around pistons; the spiraled feature, being chiefly advantageous in that it facilitates the work of repacking such joints. Lubri- cating such packings with oil and graphite naturally tends toward a reduction of friction between the mov- ing and stationary members of the engine or pump and thus more efficient operation is secured. Conclusion. As should be obvious even from the meagre story of constructions and requirements which we have been able to give in the short space allowed in this chapter The B. F. Goodrich Company has devel- oped from time to time remedies and cures for hundreds of packing troubles arising in the engineering field. This process of evolution, we may say, is yet by no means complete and we are from day to day, successfully meeting new demands for steam lines, hydraulic eleva- tors, oil pumps, chemical lines, or whatever field of application we meet as engineers vary the construction details of their machinery in temperature and pressure measurements. This system of packing study on the part of our trained experts has brought us from a meagre beginning to our present status as a leading manufacturer in the packing field and is maintaining for us this enviable position. In conclusion, we may mention that in no phase of mechanical rubber goods manufacture is the opportunity for deception so pronounced as in the field of packings. Scrap fabric is frequently made up in attractive form, 93 Rubber in Industry packed in neatly labeled containers and sold for more than one dollar per pound. Hundreds of fancy types have been developed and advertised to meet special requirements, selling at high prices, none of which have qualities to recommend them for a peculiar service over the standardized packings as supplied by Good- rich. We, therefore, feel justified in making the as- sertion that the Goodrich line embraces types of proven value and real worth only, made to meet all conditions in industrial service in which packing plays a part. 94 CHAPTER FIVE Rubber Floor Coverings DEFINITION. Rubber Floor coverings falling un- der the category of noise-deadening, non-slippery and waterproof surfaces are frequently confused with linoleums and vice versa. In fact not a few believe the terms to be synonymous. Such, however, is not the case linoleum being a compounded material of ground cork and various other filler ingredients held together by a binder of oxidized linseed oil over a base of scrim; whereas, Rubber Floor Coverings are compounded from various ingredients held together by a binder of vul- canized rubber; and are much more durable and satis- factory from every standpoint although not so cheap nor so widely used as linoleums. Although all rubber floor coverings fall under this one general classification these are listed under the more descriptive subdivisions of Matting and Tiling, which classes in turn are divided into perforated and solid mats, interlocking and inlaid tilings. Whatever the nature of their makeup and re- gardless of cost no other form of flooring so satisfactorily meets all requirements as a properly compounded well made rubber product. It is not only noiseless and at- tractive but sanitary, waterproof, odorless, which last linoleums are not, and wear resisting to an extreme degree. Wood, even the best quarter sawed seasoned oak is susceptible to moisture and will swell and shrink be- sides being noisy and hard to clean ; vitreous tiling is 95 Rubber in Industry not only noisy, but cold, easily broken and expensive; cement and mosaic floors are cold and hard to walk upon; linoleums frequently give off an offensive odor and are susceptible to curling and not extremely dura- ble. Rubber floor coverings on the other hand if properly made are soft and yielding to the step but not too yielding; they can be compounded in harmonious uniform colors and can be cleansed with soap and water without deteriorating in quality and appearance. Many cases are on record where interlocking tiling put down where extreme service requirements were demanded, such as in railroad stations, has outworn all materials from wood on up through steel and was still standing in perfect condition after a length of service much beyond which the other materials were worn entirely through. History. Although it is only during late years that the use of rubber as a floor covering or flooring material has been anywhere near general the idea is not by any means new. Thomas Hancock in his personal narrative relating of the early trials of the rubber industry refers to a patent which he took out in the year 1846 for such an item of rubber manufacture. In fact in his book the Government patent file itself is quoted and the patent number given thus anticipating any doubt which might otherwise arise as to the authenticity of the in- vention. Development of rubber matting has, therefore, ex- tended back for a period of more than 70 years beginning with about 1846. Rut, rubber tiling, we are told, was the idea of Charles Goodyear himself, who directly after taking out his patent for the process of vulcanization, experimented with, among other things, rubber tiles for 96 Rubber in Industry i floors which he hoped to make as brilliant in color as those of mineral, as agreeable to the tread as a carpet and as durable as the ancient floor of oak. Little did Goodyear think then that the time would come when rubber tiling would be recognized as the most satisfac^. tory and durable flooring material manufactured. The first tiling was, however, of the square block and Mosaic designs; the interlocking variety not having come into existence until several years later; or at the time the New York Belting and Packing Company purchased the patent and started its manufacture. The B. F. Goodrich Company began the manufacture of mats and matting about 1897 and a few years later at the expiration of the New York Belting and Packing Company's patent we added interlocking tiling to our line. From our meagre beginning in this direction we s have gradually expanded and developed this department until today there is no company better equipped to manufacture a product of high quality at a fair price than we. And there is no problem of rubber flooring requirements so difficult that a solution cannot be found, if it exists, by the Goodrich experimental men in charge of this division of our product. Manufacture of Rubber Floor Coverings. The x production of rubber matting and tiling as it is managed today by The B. F. Goodrich Company is by no means an unimportant process carried on under a hit or miss plan. The compounding problems which confront the analyst are real ; not only from the standpoint of service requirements but from the standpoint of production at a cost within range of the markets for such an item. In other words, floor coverings of rubber must meet in 97 Rubber in Industry competition those of all other materials including wood, cement, stone, linoleum and various other fibre com- positions intended to produce resilient, non-porous, long- wearing floors. Moreover, in order to meet these other flooring materials on anywhere near an equal price footing rubber must necessarily be somewhere near the same initial cost. Development, however, in this direc- tion has not reached the ultimate and although com- pounded floorings are being marketed which approach the price of other materials; they contain no new rub- ber and but a very small percentage of the regenerated variety. These may accordingly hardly lay claim to the name of rubber floorings and to this we may add that to date manufacturers have been unable to pro- duce a first class quality which will compete in all fields with other standard materials. And yet, insofar as we have progressed in this direction it can be said that success has been attained and for many services rubber flooring has indeed been found to be the most economical even at its relatively higher price. Since the manufac- ture of matting and tiling is not conducted by identical methods we will explain each separately in the order named. Assuming that the raw materials have been in- spected, prepared and mixed, we find the uncured com- pound in batch form as it comes from the milling de- partment. Slabs of this stock are next built up by calendering machinery to the required thicknesses, lengths and breadths, and are rolled up as are other calendered gums, on cylindrical shells being transported to the press room in this form. Here the stock is un- rolled, trimmed to the proper sizes and placed on the platen of a huge hydraulic press where it is vulcanized 98 Rubber in Industry under pressure, receiving at the time its permanent^ form and design. Matting of this character is generally furnished with corrugated, pebbled, knurled, or other style of rough- ened surfaces which designs are secured through the employment of engraved steel plates pressed between the upper surface of the mat and the upper jaw of the press. Occasionally it is desirable to have an insert of fabric in matting of the cheaper quality in order to give it more strength. Where such is the case it is merely necessary to calender our stock in two pieces interposing a frictioned fabric just prior to the vulcanization so that it is cured with and becomes a part of the finished mat. Although in some few instances we make a matting with a fabric insert this practice we do not recommend, since it has been our experience that the slightest abuse tends to separate the upper and lower layers of rubber from the insert and that it is far better to use an all rubber mat of a higher grade gum. If the product of this process is to be known by the trade as "Solid Matting" it is now ready for the market but if, on the contrary it is to fall under the designa- tion of "Perforated Matting," then one other operation must be performed before the product is considered as finished. This is the perforating, i e., the cutting of the open-work design so often observed on mats found in and in front of elevators, in public entrance halls, on stair landings, etc. in stores and office buildings. The vulcanized solid mat, therefore, is taken to a long table where on the upper surface the design is carefully traced in chalk from patterns, the perforating being subse- quently done by means of dies and punches especially designed and made for this purpose. On account of the 99 Rubber in Industry • ' variety of patterns desired and the impossibility to con- struct machinery for each pattern to be cut this work we may assume, is usually done by hand. To this we may add that mats of this character can be made with the firm name, facsimile signature, street address or monogram, either in the color of the mat or inlaid in a different color. Such designs make excellent advertising and are usually in demand for entrance halls, of depart- ment stores, office buildings, etc. The backs or bottom sides of solid and perforated mats may be made smooth. The practice usually followed, however, and the one we observe is to cure on pieces of coarse wet fabric pro- ducing a roughened surface, thereby insuring that the mat will remain stationary on the floor where it is used. The raw gum for interlocking tiling is calendered on small mills to approximate thickness being taken off in slabs of convenient size for handling during the punch- ing operation which is to follow. These are then re- moved to an ordinary type of punch press into which they are fed and stamped or punched, after the manner of metal, into shapes similar to those in which the fin- ished units are to appear. Those roughly formed pieces are next placed in multiple cavity molds and the molds squeezed between the jaws of hydraulic presses where the stock is cured into its final form and shape. The units are of two sizes and shapes, the smaller be- ing made with four sutures into which are fitted four dovetail projections molded to the larger blocks. Thus absolutely tight, non-movable joints are formed. We can perhaps better illustrate this by mentioning that the same system of dovetails and sutures is used on puzzles and divided maps such as are used in grammar 100 Rubber in Industry schools and kindergartens. Interlocking tiling although ordinarily made in standard colors may be furnished in any hue or shade desired merely by the addition to the compound during the milling process of the proper pig- ment. From this statement it will, therefore, be seen that this type of flooring may be made to harmonize with any set decorative scheme or made up in variegated patterns and designs to suit the taste. Inlaid tiling is constructed of square blocks usually about XYi&XYi inches in variously colored combinations, pieced together diagonally in checker board array, i.e., so that each alternate block is of a different color. Two, three, four, or in fact as many colors as may be desired may be combined in one piece although the usual prac- tice is a combination of but two. These colored blocks are as may be presumed, cut from calendered sheets of raw compound being pieced together and held in place on a long calendered sheet of stock with a fabric base as a foundation. To this they are carefully cemented with a high grade solution. Subsequently, this combination of base and inlaid or overlaid pieces is squeezed between the jaws of a hydraulic press under enormous pressure at which time the various pieces are united firmly together and vulcanized into permanent form; a substantial product of practically one piece re- sulting. Solid and Perforated matting may be made in any size and shape and in any thickness between J and 1 inch inclusive. Length is only limited by desire and width by the imitations of the hydraulic presses by which it is cured; the widest in general use now being sixty (60) inches. This feature is one which recommends Solid and Perforated matting for so many miscellaneous 101 Rubber in Industry uses demanding various shapes and sizes. Interlocking tiling can of course, be laid continuously without a break over any area of floor space. This product is, however, generally, made f inch thick. Inlaid tiling is limited in length only by desire and the bounds of practicability but in width to 57 inches on account of the fact that after vulcanization this type of rubber floor covering must be buffed and finished and present equipment is such that widths greater than 57 inches cannot be handled. The Use of Rubber Floor Covering. While we are not so bigoted as to make the claim that rubber mats, matting and tiling, constitute the ideal flooring for every condition of service yet these are adaptable to thousands of places where an attractive, noiseless, and long wearing material is desired. No other material surpasses rubber in excellence of tractive qualities; no other floor covering is so noiseless, so durable, or so easily cleaned and unless abused rubber mats, matting, and tiling, where used in their proper respective fields will last for years. The general public is daily becom- ing more and more alive to the truth of these assertions which statement is exemplified by the fact that so great is the demand for Goodrich matting and tiling becoming that it requires a separate department the sole efforts of which are devoted to the manufacture of these items. On account of their durability and safety perforated and solid mats are in universal demand for floor cover- ing in elevators and entrances to buildings. Small mats are used on porches, in front of switchboards, in auto- mobiles, around barber chairs, and billiard tables, under cuspidors and on stair treads.) Interlocking tiling is 102 Rubber in Industry found to be particularly suitable material for flooring the lobbies of public buildings and especially on account of the noiseless and sanitary features this type of floor material is to be recommended for use in all rooms of hospitals. Interlocking tiling is a superior floor ma- terial in the home for bathrooms and kitchens and is used advantageously on steamships in places where countless feet are almost continuously treading. Gym- nasium floors overlaid with this type of rubber floor covering are springy and durable, easy to the tread and furnish when waxed an ideal surface for dancing. In stores and banks where considerable standing is neces- sary they are also much appreciated because they add greatly to the comfort and efficiency of the worker. Inlaid tiling has been used principally in the aisles of electric interurban and steam railroad coaches, in Pull- man cars, for passageway flooring on steamers and as hall runners in hospitals, offices, and other public buildings. Unlike printed linoleums, inlaid tiling re- tains its luster and brightness the pattern in its original form remaining until worn down to the very base. For club entrances, vestibules of stores, office buildings, hotels, etc., -a center panel inlaid with the name and street address is extremely attractive as well as effective advertising. This floor covering material can be made in various thicknesses and any combination of color surface may be had. Care of Rubber Floor Coverings. Under normal conditions Goodrich rubber floor coverings will last for years for the stock is tough and enduring having been developed expressly for the service to which it will be put. It stands to reason, however, that no rubber 103 Rubber in Industry matting or tiling, regardless of how good, will stand up under abuse and the best will succumb to the attack of oil or grease and other natural enemies of rubber. Porters and janitors are often careless in the handling and cleaning of such floor materials. As a rule, a rubber mat is much heavier than one realizes and if caught by the corner and dragged will soon tear. Such an injury is irreparable. When necessary to move rubber mats they should be rolled up, not bent or folded, since such treatment will cause them to crack and tear. They should be washed with soap and water preferably the kind of soap which contains no lye and above all rubber mats, matting, and tiling should be laid on a firm, level foundation where they will not be subject to slipping and bending. 104 CHAPTER SIX Miscellaneous Articles AMONG the almost numberless articles falling under the general classification of Mechanical Rubber Goods there are many which on account of the special procedure followed in their construction, do not fit well into any of the conventional groups just previously treated. The best, therefore, that we can do with these is to classify them as Miscellaneous Mechanical Rubber Goods. There are a great many of these; in fact the number is so large that it would be impossible to do justice to each in the short space which we are allotted for this chapter. We will, therefore mention only a few of the more important describing their manufacture in the briefest possible manner. These are Rubber Thread, Rubber Rolls, Deckle Straps and Glazing or Channel Rubber. Our description of each will follow the same order in which we have enumerated them without further introduction. Rubber Thread. Nadier, an Englishman, in 1820, invented and patented a method for cutting thin sheets of rubber into narrow strips or threads. His purpose was to secure a material suitable for weaving fabric from which he might construct waterproof garments and he intended to accomplish this much after the same general method as employed in fabricating cloth. Al- though on account of the peculiar characteristics of rub- ber Nadier's idea was then found to be impractical in 105 Rubber in Industry the field where he wished it to be applied he neverthe- less, through his invention, opened up a field for devel- opment which has since played a strikingly important part in rubber manufacturing history. Following the discovery of vulcanization which gave to rubber both life and permanence of form rubber thread was soon included in the production of many useful articles. Chief among such were golf balls and various articles of wearing apparel such as suspenders, garters, belts etc. The stocks from which rubber thread is constructed vary in quality from pure gum to highly compounded mixtures depending entirely upon the use to which the thread is later to be put. In the production of this important item of rubber manufacture the various batches after passing through various preliminary stages are calendered into long sheets of the required thickness being at the same time wound into liner strips upon cylinders and transported to the manufacturing depart- ment in this form. Here the sheet is first unwound and thoroughly soap- stoned, i.e., dusted with talc on both sides that the sur- face may be kept from sticking at the same time being rewound onto a drum within the folds of a long muslin bandage. In this shape it is placed within an open steam pot vulcanizer and cured. The cured sheet is then taken out of the windings of fabric and rewound on a large drum under tension. These drums which are approximately eight feet in diameter are in fact part of the thread cutting machinery and revolve in front of a circular knife which being placed against the rubber and itself revolving on an automatically adjusted worm, travels from one side of the drum to the other thus cutting the thread as it progresses. The result is sev- 106 Rubber in Industry eral hundred pieces of thread between sixty and seventy yards in length. Sizes are varied by changing the worm and by using different thicknesses of stock; standard diameters ranging from J to -^ inch square. After being removed from the drum rubber thread is washed, inspected and skeined or wound upon spools ready for use. Rubber Rolls. For parts accessory to various ma- chines and sundry mechanical office appliances, Rubber Rolls are preferred in a great many instances to those made of steel or other materials and have been used since even before the discovery of vulcanization in 1839. Indeed, Rubber Rolls are not infrequently necessary to the success of the device of which they form a part. The R. F. Goodrich Company began making a feature of this branch of rubber manufacture in 1882, and through improvements in methods and equipment have pro- gressed to the point today considered as one of the largest Rubber Roll manufacturers in the United States. The present demand for Goodrich rolls was not created in a day but came only after our experts in research and manufacture had proved conclusively their ability to meet any and all service conditions under which Rubber Rolls must operate. Although the paper mill industry constitutes the largest outlet for this department and we have made remarkable progress in securing a large volume in this specific field there are nevertheless, hundreds of other uses for Rubber Rolls which we are prepared to meet. Ry way of illustration, the more common ones of these are for clothes wringers, typewriter and adding machine platens, feed rolls for typewriters and adding machines, 107 Rubber in Industry printing press feed rolls, printers' inking rolls, bean sorting machinery, box sealing machinery, tanning machinery, garment manufacturing machinery, etc. As may be imagined from the nature of their use Rubber Rolls are nearly always built on cores of metal. The first step, therefore, in construction following the preparation of materials and the milling of the com- pound is the cleaning of the surface of this core. In the manufacture of paper mill rolls which we will describe as illustrative of roll manufacture in general, a coating of cement is first applied to the metal cylinder or rod the first layer of rubber then being imposed by hand. This first ply of rubber is so compounded as to cure hard thus forming a non-separating base for the softer compound afterwards built upon it which procedure is only one of the refinements of roll manufacture. But — one which is nevertheless necessary to the pro- duction of a first class roll, since the softer compound necessary for the surface will not adhere permanently to the steel core but rather tend to loosen as the stock is alternately compressed and released in service. All rubber roll stocks are received into the building department in calendered sheet form, being reduced to thicknesses necessary according to the type of roll being covered. From this stock the core is covered ply upon ply until the necessary depth of rubber as outlined in the specifications has been reached. Steams are butted and also staggered, which is to say that in order that the compound will be of uniform thickness throughout and in order that there will be no joints registering in the plies each is the exact width of the roll circumfer- ence and when imposed the seam is not permitted to register with the previous one. After the building 108 Rubber in Industry is complete, the entire roll is wrapped with wet bandages, placed within the vulcanizer and cured to its permanent form, after which operation the roll is sometimes placed on a lathe and turned down to very exacting dimensions and conditions of smoothness. To this we may add that paper mill rolls must vary in density and grade according to the ideas of the various manufacturers, but the hardness and quality is governed to a large degree by the pressure under which each is operated, the length and diameter of the core and the thickness of the rubber coating. Inasmuch as there is a variety of service conditions to be met on a single paper making machine it must be seen that the different purpose rolls must vary in character according to their use. In other words, the press rolls, wringer rolls, couch rolls, and suction rolls each perform a different service and are accordingly made in a different manner. We are prepared to furnish several grades in each type covering a price and density range which will meet the demands of almost any mill man's desires as well as all necessary requirements. Deckle Straps. The most universally used type of paper making machine — the Fourdrinier — requires two square endless rubber straps, varying from 13^x1}^ inches to 2^x2^ inches. The purpose of these is to prevent the solution of fiber and water, termed pulp, from running off the shaping machine "wire" as the fiber is aligned and a portion of the water removed from it between the machine chest and the rolls. These moving rubber parts termed "Deckle Straps" are constructed from long narrow calendered strips of sheet rubber and frictioned fabric; and with all four 109 Rubber in Industry sides slightly concave. This special feature permits thf strap to be reversed when one edge becomes so worn that it will no longer adhere closely enough to the wire on the table to give a uniform edge to the paper. Fabric insertions placed relatively to each other like the spokes of a wheel are built into the construction which is to say, no two are parallel to each other nor to the sides of the strap. Thus, undue strain at any point is pro- vided against while the strap is passing over the deckle pulley. Vulcanization is effected in hydraulic presses in sections of about 18 feet during wh ch operation the concave in the sides is secured and the strap given its permanence of form and shape. Glazing or Channel Rubber. Vibration soon cracks putty and other dough glazing materials making them impractical for use around automobile windshields, elevator doors, car windows, steamship portholes, etc. Therefore Channel rubber is employed wherever window glass is subject to constant vibration. In modern office building construction, steel is today largely employed for the window sash and here also Channel rubber must be used since putty will not adhere well to metal. Although sometimes molded into short sections from sheet stock into patterns to fit various makes of auto- mobile windshields, porthole glass, etc., Channel rubber is usually produced in long strips. When constructed in this form the standard tubing or spewing machine is employed batch stock being fed into the hopper issuing from the die in shapes approximately resembling those desired in the finished product. This is afterward cured in multiple molds on hydraulic presses, section at 110 Rubber in Industry a time. The molds being squeezed down upon the stock by the jaws of the press, give the rubber its shape and finish which is retained by the vulcanized product. Ill CHAPTER SEVEN Marketing Belting, Hose, Molded Goods, Lathe Cut Goods, Packing, Floor Coverings, Etc. Selling. Goodrich Mechanical Rubber Goods are marketed through an organization composed of repre- sentatives who are concerned solely with this one division of our output. This organization as may be imagined, is split into divisions according to products sold or channels of trade. Thus, sales of all Mechanical Goods to Railroads come under the supervision of a division of the organization concerned solely with the business we secure from the transportation companies. Molded Goods are also marketed through a separate division of the organization and Mats, Matting, Tiling and Rubber Rolls are marketed through another. The field representatives of these various divisions covering territories which come under the supervis on of our various branches where Mechanical Goods stocks are carried are under the supervision of the Managers of the several branches. Rranch Managers in turn are made responsible for the sale of Mechanical Goods in their territories subject of course to the general rules of the corporation and under the supervision of the Mechanical Sales Manager at Akron. On account, how- ever, of the wide diversity of markets for the mechanical line no hard and fast rule can be laid down and main- tained for long, relative to supervision of sales. In con- 112 Interlocking Tiling Wire Drawing Machine No J standard. Sin die Conductor. Lead Encased. MFCS. Flexible, Dup, Minin Solid, Lead l fflfmij Flexible Single Conductor. TwoBraids. WeatherprooF MFCS. m Stranded, Single Conductor. TwoBraids. WeatherprooF MFCS Solid, Duple; We at k Stranded, J Wed. Plain Rub llel and Weatherproof ine Cable (tlMSMglil Z e<3 d Press Depi Cab le Press No t. ■Parallel, d.NZ.CS. GOODRICH STANDARD 'el. Braided and N.E.CS. inductor. Single Braid of N.E.CS ?red Secondary Cable Goodrich "Standard" Concentric Mining Machine Cable Duplex Automobile fighting Cable """" ! "" —' MHHB Braided Secondary Cable. Rubber Pump Valves Packing Rubber in Industry sequence, some representatives from the Mechanical Sales Department although making their headquarters at one of our various branches are supervised in all of their activities by the Akron office. Channels of Distribution. The sale of Mechanical Rubber Goods is so involved and complicated with vary- ing trade conditions that no cut and dried, inflexible rule concerning the channels of distribution employed and the methods of approach can be followed. In conse- quence, to those previously unfamiliar with a line of this character, the marketing plans followed often seem con- fused and somewhat inconsistent. This is a subject, however, to which in the brief space here allotted we cannot hope to do justice. We, therefore, merely out- line the fundamentals recommending that the student of Mechanical Goods Sales gain a further knowledge of this subject through a study of the booklets published by the Office of the Mechanical Sales Manager on the general subject of Sales Suggestions for Goodrich Me- chanical Rubber Goods Salesmen. As was intimated previously, transportation com- panies, paper mills, mining companies, and other large industries are frequently sold direct whereas, under other conditions the distributor and jobber is relied upon as the logical avenue of distribution. Distributors frequently and jobbers occasionally are given exclusive territories in which they are made responsible for the entire sales of Goodrich or Diamond Brand Goods and through their own sales representatives dispose of our product to mines, mills, hardware dealers, and such. In other instances these same selling agencies market Good- rich-made Special Brand Mechanical Goods to the trade 113 Rubber in Industry in competition with our own organization selling our Goodrich and Diamond Brand Mechanical products. The student may be assured, however, that the dis- tributing method employed in each and every instance is the result of careful study and intended to accomplish but one result; viz., to serve best the ultimate user of Goodrich-made products. Branch Stocks. In certain instances where indus- trial conditions demand such an arrangement in order to facilitate distribution of our product our branches carry stocks of Mechanical Goods embracing such items as have been found most in demand by the industries located in their respective territories. The advantages to the trade and consumer of having these branch sources of supply nearby from which quick delivery may be made will be readily apparent. Such stocks permit the filling of orders with the least possible delay and it is our intention to have them complete enough at all times to fill every reasonable immediate shipment order. We replenish the supply from the factory from time to time as the stocks become exhausted, thereby insuring a well chosen assortment at all times in every main center of distribution. Guarantee. The conditions under which Mechan- ical Rubber Goods are used are so beset with chemical and mechanical problems and subject to uncertainties of care and abuse that very rarely is it possible for the manufacturer or seller to guarantee any definite dura- tion of life for such products of the rubber factory. Since, however, this is the generally accepted principle in the field of commerce we need not dwell upon this point further than to mention that occasionally manu- 114 Rubber in Industry facturers are found who are apparently guaranteeing their product for definite units of service, in defiance of this law. In this connection we desire to voice the warning that where such a state of affairs is met with by the user, the jobber and retailer of such merchandise, we should look for "fire." For no manufacturer of Mechanical Rubber Goods, be he thoroughly honest in his intentions can afford to go beyond the guarantee which we and other responsible companies maintain. The R. F. Goodrich Company guarantees every product marketed under its own brand names and in most instances Goodrich-made private brand goods as well to be free from defects in material and workman- ship, and to give reasonable length of service in the fields where each is intended to apply. Furthermore, we protect all consumers of Goodrich and Diamond Mechanical Goods against defects in material and work- manship and make good whenever from these causes our products fail. We realize, however, and wish to point out, that there are other elements entering into the causes of failure besides merely those of workmanship and material. Therefore in dealing with the consumer and trade on the question of adjustments where failure is met with we take these into consideration. Ry this we mean that it is recognized that a certain moral responsibility rests upon the Company for the recommendations and actions of its salesmen. This, however, is a subject upon which so much might be told that we cannot here give the time and space for thorough treatment. Ac- cordingly, we leave this phase of the manufacture and sale of Mechanical Rubber Goods to further study on the part of the student of this business. 115 Rubber in Industry The following episode, however, which occurred in connection with the beginning of The Goodrich Company and White Anchor Hose shows very plainly the spirit of fair dealing that has been embodied in our manufac- ture of rubber goods from the start, and although it has been related many times, a retelling may prove to be of interest. It seems that one of Akron's celebrities had purchased a couple of lengths of White Anchor expecting the ordinary, to which he had been accustomed, and was surprised at the workmanship. "What d'ye make this hose so good for, Doc?" he asked. "None of the other fellows do." "Just pure selfishness," was the reply. "It makes me nervous to have people kick — and besides, I'd lose money in the long run." So from the start, because we believed firmly that success played no favorites, and all so-called secret ways to this goal were largely contained in the ability to impress the public of the worth of "worth while" goods that we have succeeded in the Mechanical Rubber goods field. It is this belief which has ever stimulated The Goodrich Company in placing its products on the mar- ket, and it is this same belief which has led us to in- corporate into the construction of our whole mechanical line the best that our experience and knowledge of rub- ber permits. In the manufacture of this line we are constantly asking ourselves these questions: "Will this hose or belt qualify when measured by the Goodrich standard?" "Will it adequately take care of the work for which it is intended?" "Is it really worth while?" 116 INTRODUCTORY Insulated Wire AS we sit at our desks in a flood of light and tele- phone to our friends and business acquaintances, or as we ride home on the street car, few of us stop to realize what an essential part Electricity and InsuJated Wire play in everyday life. Let us, therefore, pause just a moment and consider the force which lights the lamp, transmits the voice to the listening ear, and rotates the wheels of the car— ELECTRICITY. Then let us think of the medium through which this mysterious force is conveyed from the roaring generators at the power house or from the silent storage batteries under the seat, to the point where it is converted into light or power — WIRE. Wire alone, could not transmit the "juice" for other bodies have a tendency to rob it of the precious charge. Electricity would never reach the lamp, the receiver, nor the motor, but would leak out or be stolen before it had gone far on its way were it not for the restraining influence of that something which supports or is wrapped around the wire— INSULATION. In the preparation of this section we are at the very outset confronted with the most difficult of problems; namely, the selection of the material which will be of most value to the class of readers whom we are en- deavoring to reach. A product so vital to our industrial life as Insulated Wire has become presents a subject so great that we have always to keep in mind the necessity 117 Rubber in Industry and inclination of those directly concerned as well as our own desire to pass along to others knowledge of the subject, which we have gained. The number of suit- able topics is far greater than can be well handled in a text of this kind however substantial it may be. In the selection of our topics we have, therefore, arrived at our result by a process of elimination, choosing only such as we believe to be of essential interest to those this book is likely to reach; whether or not they may intend to continue their studies further in this direction. To understand any mechanical device clearly one must know something of the force with which it is as- sociated its use, its requirements and developments; hence the chapter on Electricity, its History and Com- mercial Application. The very nature of this subject, however, is such that anything written concerning it may not be comprehended at a glance or by indifferent reading such as we generally follow in scanning our newspaper. But we believe that everyone should have some definite knowledge of the matter treated and have bravely disregarded the limits of a few theories in order to state the various principles in terms that may be readily understood. 118 CHAPTER EIGHT Electricity (Insulated Wire) COMPENDIUM. About 2500 years ago students observed a certain peculiar phenomena in connec- tion with Amber, a substance to which the Greeks had applied the name "Elektron." These observations were regarded by writers who, as was usual in such cases, fell back upon the supernatural for an explanation and ascribed to the substance certain mysterious qual- ities. Development was so slow that people knew practically nothing about electricity up to the beginning of the Nineteenth Century. Few discoveries were made and such as were, dealt only with electricity at rest (static electricity). Although the condenser — that most important electrical instrument which now occupies a high place in telephony and wireless telegraphy — had been devised its use was confined to laboratory pur- poses. Almost the only practical electrical invention was the lightning rod ; and its usefulness was much over- estimated. Nevertheless, electricity was the most ab- sorbing topic with which scientific men dallied during the Eighteenth Century. It was lectured about and demonstrated to large audiences; and was as much talked about by everybody as radium or wireless tele- graphy have been recently. But still it was merely a plaything in laboratories. In the last half of the Nineteenth Century, however, 119 Rubber in Industry electricity suddenly became "galvanized" into action and soon reached a commanding position in the arts and engineering. Probably no more spectacular service has ever been rendered to the welfare of mankind by what practical men like to call "pure science." The story of this highly technical development is a most con- vincing answer to those who, even now, distrust "pure science" and "technical men" as "impractical" and "useless." What is Electricity? At the very outset we are compelled to admit that we do not know what elec- tricity is. It is not matter, since it is devoid of physical dimensions and weight; yet in its production, trans- mission and manifestations it must always be associated with matter. Mechanical or chemical energy applied to matter at one point may be used to produce elec- tricity which may be transmitted to some other point and there used to reproduce energy of either kind. Its great value to the industrial world exists in this very ability to transmit energy instantly great distances and to deliver it with minimum loss. Fortunately, however, for our purposes a theory is not essential; and although our knowledge of this force is restricted to the various phenomena which it produces, so are the laws which govern the manifestations of many other forces, which to the layman seem less mysterious, not well under- stood. Nomenclature. During the reign of Queen Eliza- beth, a certain Dr. Gilbert, an Englishman, carried out a series of very remarkable experiments and observa- tions upon the then vaguely known properties of mag- nets. And, as allied to magnets, investigated other 120 Rubber in Industry bodies in which powers of attraction could be produced. He discovered that this property was by no means con- fined to Amber; and in 1600 he enumerated a list of several other substances which also possessed it. He mentions among others the Diamond, Sapphire, Opal, varieties of Rock Crystal, Glass, Fluor Spar, Rock Salt, Mica, Sealing Wax, Resin, Jet, Sulphur, etc., and to all these bodies in which, like Amber or "Elektron" the power of attraction could be produced by rubbing, he applied the term "Electrics." From this it was an easy transition to the word Electricity. ZINC CLOTH CLOTH The Electric Battery — Volta. For nearly two thousand years, friction and in- duction were the only methods known for producing electricity. But, in 1786, an unexpected obser- cloth vation of the Italian anatomist, Galvani, of Bologna, started a series of most important discoveries and inventions. He observed that the legs of frogs which he had been dissecting twitched with each dis- charge from his static machine. Later he discovered by experiment that if strips of two different metals, such as copper and zinc, were fastened together forming an inverted V, and their free ends applied to frogs' legs there were the same nervous twitchings as followed the discharge of static electricity. He, therefore, determined that electricity was formed through the contact of dis- similar metals. Volta, who while investigating this question sometime after this invented a chemical 121 Rubber in Industry method for producing electricity continuously. This is now called an electric battery. Voltaic Battery. A glass tumbler, with a strip of zinc * X fl and a strip of copper dip- II ping into dilute sulphuric 5 ^ y acid is one form of voltaic COPPER ce jj an( j w h en several cells are combined, they consti- tute a battery. With slight modifications the batteries of today follow the general principle de- veloped by Volta, and as a mark of respect, his name is universally used as the unit of electromotive force — the "volt." Magnetism. Sometime in the remote past one of the ancients stumbled over a piece of brown colored stone (known to us as magnetic oxide of iron). Upon examination, he found that it possessed a peculiar property of attracting other small pieces of the same material and likewise, particles of iron and steel. The Compass. Later the Chinese discovered that if a piece of this ore were suspended by a string in such a way that its free action was possible, it possessed the important property of pointing always in a particular direction, nearly North and South; hence they gave it the name of lodestone (meaning leading stone) and used it in this manner to navigate their ships. Artificial Magnets. Lodestone possesses a third im- portant property, that of imparting its properties to a piece of hard iron or steel when the two are rubbed 122 Rubber in Industry together, without apparently losing its own original force. Compass needles and horseshoe magnets as seen in the modern automobile magneto, are practical exam- ples of the value of this discovery. Such magnets are, however, not made by rubbing the metal upon "lode- stone" because its magnetic force is not strong, but by the better method of employing electro magnets and coils of wire. This will be described later. Polarity. The ends of a magnet are termed its poles. The end which points toward the North geo- graphical pole is generally called the North or plus ( + ) pole, while the other end is the South or minus ( — ) pole. Just as the male attracts the female, so does the plus pole of one magnet attract the minus pole of another but, when like poles approach each other the repulsion is almost as great in that case as the value of the at- traction in the other. Magnets grow stronger and re- tain their strength indefinitely when their unlike poles are connected by keepers — small bars of soft iron. Value of Polarity. The principle of all electric motors is based on these attraction and repulsion characteristics of magnets. With this fact in mind it will be readily appreciated how if a bar magnet be balanced upon a pivot where it is free to turn, and the North Pole of another strong magnet held in the hand away from, but in the path of the first magnet, the South Pole of the first will be drawn towards the position of the North Pole of the second and the mounted magnet will turn on its pivot. If, when it approaches the position of the second magnet, the ends of the latter are sudden- ly reversed so that its South Pole comes in the vicinity 123 Rubber in Industry of the South Pole of the swinging magnet the latter will be repelled and continue to turn upon the pivot. Providing the manipulation of the second magnet is properly timed, the first may be caused to revolve con- tinuously. It was early discovered that if strong magnets were employed and the revolving member fixed to a shaft the power developed might be used to do work. But the strength of permanent magnets of convenient size was found insufficient for commercial purposes. So the introduction of the electric motor was delayed for some one to invent a stronger magnet of reasonable propor- tions and an automatic device for reversing the polarity of the fixed magnet. Magnetic Force of Electric Current — Oersted. In 1819, the Danish physicist, Oersted, made a discovery which, because it was the first evidence of a connection between magnetism and electricity aroused the greatest interest and paved the way for the electric motor. He found that when a wire connecting the poles of a voltaic cell was held over a compass needle, the north pole of the needle was deflected toward the west when the current flowed from south to north; while a wire placed under the compass needle caused the north end of the needle to be deflected to the east. Inasmuch as the compass needle indicated the direction of magnetic lines of force 124 Rubber in Industry it is evident from Oersted's experiment that a current must set up a magnetic field at right angles to the con- ductor. Electro-Magnets. Lifting Magnet From Oersted's discovery, it was an easy step for Joseph Henry, an American school teacher, and Michael Faraday, an English chemist, both of whom in 1831 dis- covered that a piece of iron assumed the pro- perties of a natural magnet when placed in the vicinity of a cur- rent bearing wire, to make the first electro- magnets by coiling insulated wire about a soft iron core. Henry. In recognition of Henry's genius, the unit of induction is called the "henry" by the electrical in- dustry. The wonderful magnetic hoists now employed so generally in the steel industry and elsewhere to move steel rails and heavy iron and steel masses are develop- ments of Henry's invention. These commercial mag- nets are capable of lifting 100 to 200 lbs. of iron per square inch of pole face, and yet release the load the moment the current is cut off. Faraday. For the basic principles of the dynamo, motor, electric bell and buzzer, electric gear shift and many other such devices we are indebted to Faraday. 125 Rubber in Industry MODERN ELECTRICITY The Telegraph. In 1844, S. F. B. Morse invented an instrument based on Faraday's discoveries and, be- cause it enabled him to write at a distance — tele-graph, The Telegraph ^ he named it the telegraph. Now, through the inventions of Edison and others we are able to send two messages simultaneously in each direction. In other words we can send four messages over a single wire at the same time. This is called quadruplex telegraphy. The Dynamo and Motor. If today we were obliged to depend upon batteries for our electric current we would not be lighting streets and houses with electric lamps, riding on electric cars or driving the great ma- chinery in the Goodrich Plant by electric motors. The cost of zinc or other metals as a fuel in the voltaic cell makes the battery too expensive as a source for large quantities of electricity. Among other things, Faraday discovered that when a coil or bundle of wire is rotated between the poles of a permanent or an electro-magnet, a current will be set in motion within these coils of the wire which, when suitable connections are provided, may be carried out through other wires and thus converted into force. So was the principle of converting mechanical energy into electricity discovered and the dynamo invented, making possible the present electrical age. Nevertheless, it was left to Edison, Tesla, Westinghouse and others to invent 126 Rubber in Industry the means by which the current created in the dynamo could be made to do mechanical work. Of all these later inventions, those of Thomas A. Edison, the direct current generator and motor and the Edison three-wire balanced system of electricity distribution, are relatively the most important. Definitions of Electrical Terms. Before we go farther it will be well to define briefly the two com- mercial forms of electricity which are at present of the greatest practical value. The flow of electric current "When the magnet is moving in and out of the coil a current of electricity is generated. Thus the principle of all generators of electricity is illustrated." — Robinson. may be said to be analogous to that of water and al- though at variance with theory, a comparison between the flow of water and that of an electric current is not in error to such an extent that it may not be used here for the sake of clearness. Imagine, if you will, a pipe conducting water from one place to another and then think of an electric current flowing through or over a wire from a battery or generating station to a point where it is converted into light, heat or power through suitable apparatus. 127 Rubber in Industry Direct Current. If the flow of current in either of the two wires, which are necessary to complete an electric circuit, is continuous and constantly in one direction the electricity is said to be direct current (D.G.) Alternating Current. If, however, the course of flow is constantly alternating from one direction to another in each wire at frequent intervals, the electricity is said to be alternating current (AG.) Circuit. It is well to note here, by comparison, the difference between the flow of water in a pipe and the flow of electricity over a wire. If a pressure be applied to water at one end of a pipe and the other end left open the water will run out and flow freely, but elec- tricity must be provided with both an outgoing and in- coming path in order to produce a current to flow; con- sequently one always hears the path of electricity des- cribed as a "circuit" the word being derived from "circle." Volt — Ampere. In the case of water, the quantity dis- charged at the end of the pipe depends upon the cross section area of the pipe and the pressure exerted upon the body of water. By way of comparison, the unit of pressure of electric current in the wire is the Volt and the unit of intensity or of current flow is the Ampere. The number of amperes in a circuit depends upon the connected load, i.e., size and number of lamps, motors, etc. supplied, and determines in a large measure the size of wire to be used in making connections. It is reasonable that no more current (Amperes) will flow through the circuit than that required to do the work connected in the circuit. The number of amperes in a circuit may be determined by dividing the watts by the voltage of the circuit which latter is usually constant. 128 Rubber in Industry Resistance. The term applied to the force with which all materials oppose the passage of an electric current is Resistance. Therefore, in converting electric energy into any other form resistance must be encountered and overcome. The unit of resistance is the ohm and the resistance of the average 100 W. lamp is 121 ohms. All electrical measurements are based upon these three terms — Volt, Ampere, and Ohm; and the equation: — I=| (Ohm's Law) expresses their true relationship for Direct Current. Volt. (E) or Electro-motive force — the Unit of Pres- sure. The pressure that will cause one Ampere of Current to flow through a resistance of one Ohm. Ohm (R). The Unit of Resistance — the Resistance which will permit one Ampere of Current to pass when one Volt of Pressure is impressed on the Circuit. Ampere (I). The Unit of Intensity or Current Flow. The intensity of the Current that will flow through a Resistance of one Ohm under the pressure of one Volt. Watt — Kilowatt. In the case of water the quantity discharged from a pipe is known as a certain number of gallons. The quantity of electricity passing a given point in the electric circuit is measured in terms of the Watt (Volts x Amperes) . Thus when we say a lamp consumes 100 watts, we mean that 100 watts of elec- tricity are required to pass through it every hour in order that it may deliver its rated .candle power of illumination. When watts are to be considered in large quantities 1000 is used as a factor and the unit measure- ment is known as the Kilowatt (1000 x Watts) . Thus when we speak of the price of electricity as being 10 cents per Kilowatt Hour, we understand that the cost of operating ten 100 watt lamps for a period of one hour is 10 cents. 129 Rubber in Industry Transmission of Electric Current. A character- istic difference between Direct (D.C.) and Alternating (A.G.) current lies in the distance to which each may be transmitted. The transmission of direct current (D.C.) is restricted to a comparatively small radius of a few miles; owing to the enormous cost of the large wires required to accommodate the current at the rela- tively low voltage to which the generation of direct current is limited. The exact limit of the distance to which alternating current may be transmitted eco- nomically has not been definitely determined but the present practice covers hundreds of miles. By the use of transformers, alternating current (A.G.) may be given any desired voltage. 100,000 volts seems to be the practical limit in present high tension practice. The higher the voltage impressed, the smaller the wire necessary to serve a certain capacity. The possibility of generating and transmitting alter- nating current had been known for some time but a theory for the development of apparatus which would efficiently employ and convert it into useful work was not discovered until comparatively recent years. The ordinary incandescent carbon or tungsten lamp will operate on either alternating or direct current of a given voltage with good results, but arc lamps and motors must be especially designed for each class of current. Even the suggestion of an alternating current motor was at first scoffed at by such great men as Edison, but it is pleasant to know that when George Westinghouse invented the present efficient alternating current apparatus Mr. Edison was among the first to recognize his genius and extend to him the appreciation of the world. It was Mr. Westinghouse who made 130 Rubber in Industry possible the great hydro-electric stations at Niagara Falls and various other points, that are converting waste water into electric energy which in turn is trans- mitted by wire to distant places and there converted into useful work. Many evidences of the genius of George Westinghouse are to be found in "The Greatest Rubber Factory in the World." Our synchronous, 500 Horse Power induction and D. C. motors, the turbines, generators, switchboards and lamps bear the trademark of the great institution which he founded. Transformers, Alternating current is susceptible to many changes and conditions to which direct current may not be applied. Most important among these is the transformation feature, an apt illustration of which is to be found on the automobile employing a spark coil. By the spark coil or transformer, we take a pulsating or interrupted current of about six volts and "step it up" to several hundred times that value without employing any moving parts, at the same time sustaining very little loss of force. In the high tension or high voltage transmission lines radiating from the great central stations at Niagara and other points which cover almost the entire country with a network of wire, a current frequently 100,000 volts or more, is transmitted to different points and there shunted through the coils of transformers which "step it down" producing other relatively harmless lower voltages which permit of its commercial consumption freely without endangering the lives of those who operate the machines. The familiar type of transformers are those found near the tops of poles in the small cities where they are employed to reduce a transmission voltage of about 131 Rubber in Industry 2600 volts to the domestic value— 110 to 220 volt limit — in order that the electric light, iron, chafing dish, coffee percolator and foot warmer may be used in ab- solute safety. The distribution systems in larger cities, however, are often placed underground through conduits and tunnels for safety, enhancement of scenic value and the prevention of service interference, hence trans- formers are not so much in evidence in larger centers. Wireless Telegraphy. Practically all electrical de- velopments as described in the foregoing paragraphs have been employed to a great extent in the wonderful product of Marconi's genius which has served to save the lives of so many of our seafaring people. The term "wireless" conveys to the unsophisticated an idea that here is the place where wires are not employed. At the present time, every great wireless telegraph station employs hundreds of miles of wire of various sizes and forms to assimilate the force and to conduct it to the point, high above the ground, where it leaves the aerials or antenna on its trip to Honolulu, Paris or Tokio. In fact, the modern wireless telegraph station is a network of wires; and but for the advantages of the best practical insulating material — vulcanized rub- ber — wireless telegraphy would probably never have been made possible. The Primary Cell and Storage Battery. The de- velopment of electrical current from magnetism with the dynamo or generator is a most wonderful achieve- ment, but the laws governing this phenomena are well understood and the process is today highly developed and efficient. Concerning the production of current 132 Rubber in Industry flow by so-called chemical means, as in all forms of batteries, comparatively little is known; and as a result batteries as a whole are more or less inefficient. The entire upper field of chemistry is still hidden from human intelligence, but investigation and research are gradually and constantly opening up new vistas indi- cating the existence of new forces and it may be found that electricity is only a conducting medium for other forces. The battery cell is, however, very important commercially and for us to know something application. In the follow- ing discussion we will, however, in consequence of this lack of facts, be obliged to assume the right to advance ideas which have not as yet been wholly ac- cepted by science but which have been of inestimable value to us in partially clearing up a very cloudy and mysterious subject. The Primary or Voltaic Battery. All metals may be divided into two electrical classes — Positive and Negative. A member of one class, such as copper or carbon, differs from all members of the other class, as zinc or iron, and the molecular activity of one differs from that of the other. If a strip of metal of the positive class (zinc), is brought into close contact with a strip of metal of the negative class (copper), a peculiar interexchange of activity between them is set up, in cir- cular paths. Then if the two metals be placed in a it is, about Gravity Cell therefore, well its design and 133 Rubber in Industry *s of rubber, glass or earthen vessel in separate positions partially or wholly immersed in a weak solution of acid and water it will be found that the solution will permit the energy to pass from one to the other principally in one direction. To demonstrate, fasten one end of a wire securely to the copper strip of the cell and upon bringing the other end of the wire into and out of con- tact with the zinc strip a small spark will be evidence of a flow of electricity. If the wire from the copper plate be Dry Cell attached to one of the binding posts a bell and another wire led from the other binding post to the zinc plate of the battery cell the bell will ring, providing the cell and its plates are of ample size. Thus it is reasonable to believe the theory correct and to assume that different metals possess electro activity of varying nature or strength and that the activity of one has an affinity for that of the other. We know that if this tendency be properly directed it may be caused to produce electric current and perform work. One of the metals, in ihis case the zinc, will disintegrate when all of its activity is spent. Salt water may be used instead of acidulated water but the action will be weaker. Commercial Batteries. The principal commercial forms of voltaic batteries are the dry cell and the Daniell or crow-foot cell. The active elements of the dry cell are carbon and zinc and the liquid is carried in sawdust or other absorbent as it was in Volta's original pile, or battery. Dry batteries are used for automobile and 134 Rubber in Industry motor boat ignition, door bell ringing, etc., where the service is intermittent. The crow-foot battery employs zinc and copper and is so named because of the shape of the zinc element. The electrolyte or liquid used is copper sulphate (blue vitriol) and water. It is used exclusively for telegraph and other closed circuit serv- ice and is capable of delivering a continuous flow of electricity for a considerable period of time. The Storage Battery. The advent of large, centrally located electric generating stations created a demand for a more efficient form of chemical generator of con- tinuous electric current flow than the voltaic cell. This demand arose on account of the unreliability of early electrical mechanical devices. To gain the confidence and hold the respect of the public it was thus necessary to provide against the "dark" of an engine breakdown or broken belt. Such batteries are connected across the distribution circuits and act only in case of emergencies. Storage batteries will only store up and give out Direct current; consequently after the date of Westing- house's invention of the more efficient alternating cur- rent apparatus and its almost universal adoption, it seemed that the storage battery was doomed to take its place in the past with reciprocating engines, horses, low pressure steam and metal vehicle tires. But, some- body developed the "wild idea" of increasing the high cost of keeping a "flivver" by installing self-starters and a greater and more exacting demand immediately arose for the storage battery. And thus grew up an industry of today to which The B. F. Goodrich Com- pany largely contributes with hard rubber jars, insula- tors and separators. 135 Rubber in Industry Types. Storage batteries are of two general classes: viz., the Lead Type and the Nickel-Iron Type. The lead type was developed by Gaston Plante in 1860, and consists of a series of pairs of lead plates supported in a sulphuric acid solution. The plates are similar at the start but when subjected to the influence of direct cur- rent from a generator, one of each pair (the cathode plate) is converted into sponge lead and the other (the anode plate) is changed to peroxide of lead. Sponge lead and peroxide of lead possess different electro activity and as long as these two plates retain their assumed characteristics, a flow of electric current is produced and may be used to operate a motor, to crank an automobile engine or to light lamps. When this current flow becomes weak, the strength of the battery may again be restored by passing a current of a definite value from an outside source through it for a time, but in the direction opposite to its normal discharge. The potential of a lead cell is two volts and its capacity or ampere rating varies with the size of the plates. The average life of the lead battery is one year. The Nickel- Iron Storage Battery. With all forms of lead storage batteries there are certain objectionable features such as excessive weight, acid fumes and deterioration of the plates. Edison endeavored to over- come all of these objections by inventing a battery immersed in caustic potash solution. The life of this battery is indefinite and the fluid used is harmless, but the space required and cost of charging are greater; and its substantial advantage over the lead type has not yet been established. The potential of the cell is about one volt or half that of the lead cell. A peculiar feature 136 Rubber in Industry of the storage battery is that its condition of charge may be closely estimated by testing the specific gravity of the fluid or electrolyte with a hydrometer. The acid resisting quality and the fact that rubber is one of the best known insulators of electricity un- doubtedly establishes hard rubber as a permanent factor in the battery industry which, by the way, has reached enormous proportions. Although a very ex- pensive substance on account of the high quality of the crude necessary for its manufacture and the fact that the common grades of fillers may not be employed in compounding, no satisfactory substitute for hard rubber has yet been introduced. The B. F. Goodrich Com- pany contributes in a very substantial manner to the industry by supplying the most prominent manufac- turers with millions of hard rubber acid container jars, covers, vent plugs, separators and supports each year. There are several concerns making batteries, but three or four large companies manufacture almost the entire supply of the United States. 137 CHAPTER NINE Wire (Rubber Insulated) CONDUCTORS. The study of various materials for conducting or transmitting electricity from one point to another began in 1729 when Stephen Gray experimenting with electric attraction used, instead of a glass rod, a tube into the open ends of which he had stuck corks to keep out the dust. Upon rubbing the glass tube he was surprised to find that the corks which had not been rubbed had nevertheless acquired the property of attraction as if the charge generated upon the glass had spread upon them. To test this further he inserted in the corks long wands of wood or metal terminating in balls and found that when the glass was rubbed the balls attracted light objects. In place of the wands he next tried cords and wires, by which he suspended a ball from a glass tube held in a balcony above, and found that the ball became electrified as soon as the tube was rubbed. Wishing to continue this ex- periment at a greater distance than could be obtained from his balcony, he was obliged to stretch his cord horizontally, and to keep it clear of the ground he hung it up at intervals by bits of thread attached to nails in posts. Under these conditions he was unable to elec- trify the ball and he surmised correctly that the charge had escaped by way of the suspending threads. A friend who was assisting him suggested that they use 138 Rubber in Industry a finer thread which would give a smaller path by which the charge could escape; and a spool of silk being at hand, it was tried with the result that he was able to electrify the ball at greater and greater distances up to as far as 765 feet. Finally, the silk thread breaking under the strain, he tried a fine wire, even smaller than the silk, but was enable to electrify the ball and now he perceived for the first time that the escape of the charge depended, not only upon the size of the suspensions, but also upon the material of which they were made. As a result of a continuation of these experiments he was enabled to arrange in one series all bodies which he called conductors and in another those which he knew as non-conductors or insulators. For current electricity the order of Gray's series is reversed. In the light of modern investigation we now know that there is no strict dividing line between con- ductors and non-conductors and that there is no such thing as a perfect conductor nor an absolute insulator; but that all bodies offer resistance to the passage of electricity. Those that offer the greatest are termed non- conductors. Joubert concisely defines good conductors as those bodies which when electrified at one point are immediately found to be electrified all over. The dif- ferent characteristics, therefore, of the various sub- stances now employed as conductors is accounted for in a property known as resistance. Resistance may be defined as an opposing force existing in all matter which has to be overcome in order to cause a flow of electrical energy. In so doing a certain amount of energy is continuously transformed into heat so long as the flow of electric energy continues. 139 Rubber in Industry Resistance in an electric current is somewhat analogous to the resistance of water pipes to the passage of water. Gray's Experiment The greater the length of the conductor the greater the resistance, and the greater the cross section of the conductor the less is the resistance. As mentioned in the previous chapter, the unit of measurement for re- sistance is the Ohm, so named from the discoveries of 140 Rubber in Industry Dr. Simon Ohm, who in 1826, formulated a law which exhibits the relation of voltage, current, and resistance. It is, therefore, obvious that the resistance of a con- ductor of electricity should be maintained at as low a value as possible; that the cross section area should be sufficiently large to accommodate the current required by the motors or lamps served; and, that the material of which the conductor is made should offer as little natural resistance to the flow of electricity as possible. It has taken considerable research and experimenting to enable scientists to arrange the various good and partial conductors of electricity in the order of their con- ductivity as follows: Good Conductors Silver Copper Aluminum Brass Platinum Iron Lead Mercury The invention of the telegraph in 1844 created the first appreciable demand for the transmission of electric current by wire over long distances and it then became necessary to select a metal, which when drawn into wire, would best serve the purpose. Capital to finance the construction of early telegraph systems was not easily obtained, but fortunately the current necessary to operate the small and delicate relays of the telegraph set was so little that a relatively poor conductor served the purpose fairly well and iron or steel wires were used 141 Fair Partial Conductors Conductors Compact Carbon Water Acid Solutions Animal Bodies Salt Solutions Flame Living Plants Cotton Damp Earth Wood Marble Rubber in Industry on account of their relative cheapness and great tensile strength. The earth was even used in most cases for the return conductor in order that the outlay of money for wire might be reduced to the minimum. However, when the dynamo, motor and electric lamp made the commercial use of electricity for light and power pos- sible, the demand for wire instantly grew to enormous proportions; but the poor conductivity of iron and steel barred it for electric light and power work and it be- came necessary to select a more suitable metal. It was known that silver offered the least resistance of any metal to the flow of electricity but its value for electrical purposes was not commensurate with its cost. For- tunately it was found that the relative cost and adapt- ability to wire drawing of copper, as well as its high rank in the list of electric conductors made that metal admirably suited for the purpose. Mr. Edison installed copper wire in the first lighting plants and, following his lead, the telegraph and later the telephone companies appreciating its efficiency also adopted copper as the standard for their lines. The copper industry, in appreciation, recently presented to Mr. Edison a cubic foot of pure copper upon which a brief history of his achievements was beautifully en- graved. Copper is a metallic element occurring abundantly in nature and widely used in many arts. It has been worked from the earliest times, and was frequently mentioned by writers as early as 4700 years B.C. Pre- historic weapons, tools, and ornaments of copper, as well as domestic implements remain in profusion to this day; and it has been stoutly asserted that this metal 142 Rubber in Industry was known and used before iron. The Romans ob- tained their best copper from Cyprus, an island in the Mediterranean Sea, and for this reason the metal was for centuries known as Cyprium, later contracted to Cuprum and Cuper. Although today found widely distributed over the earth, the United States produces far more copper than any other country the present output being more than 70 per cent of that of the entire world. Arizona, Mon- tana, Michigan and Utah are the principal copper pro- ducing states and the most famous mines are the Ana- conda, the Boston and Montana, Calumet and Hecla and Copper Queen. In its natural state, the ore varies greatly in quality and for this reason the relatively pure product from the Lake Regions of Michigan was the highest priced for several years. But, after the refining of copper ore by electricity was developed, "electrolytic" as the product of this process came to be termed, became the standard and since any copper ore may be refined by this process the product of any part of the country has ceased to be distinctive. Although used far and wide for many pur- poses, its greatest application is to be found in the wire industry; and therefore the following discussion will be confined to the phase of copper production leading up to the development of wire. Early Industry. The copper mining industry in the United States dates from 1719, when a mine was opened at Arlington, N. J. Our production was, however, relatively unimportant and little felt until the rich mines of the Lake Regions were opened in 1864. A few years later the mines of Michigan alone produced 143 Rubber in Industry 15 per cent of the copper output of the entire world; but Michigan took second place when the series of fissures carrying copper and some silver were developed near Butte, Montana. The most famous of the Butte mines, the Anaconda, opened as a silver mine in 1880 but soon became the world's greatest copper producer. Prospecting. The copper industry is now in a most flourishing condition, but the early attempts of the pioneers were attended by heart sickening failures and great sacrifices. The early prospectors in search for ore were guided by the primitive mining implements which an earlier generation had left about the spots where they had collected mineral from the earth; but as the number of "would-be" miners increased the guidance afforded by deserted stone hammers, became inadequate to meet the requirements so other methods had to be resorted to; and finally the method which obtains at present was adopted. When the mineralogists, or evidence in the shape of out-croppings have indicated a copper deposit, borings are made of the whole vicinity and the different strata encountered are carefully studied and plotted so that the depths of the different deposits and their "dip" may be accurately ascertained. It is interesting to note that late developments have dis- closed the fact that many attempts of our earlier miners failed because they did not bore "the last few inches" separating failure from success. Mining. When an ore deposit is sufficiently ex- ploited to assure that it can be worked at a profit, a mine is located. Be it known, however, that to ascer- tain whether a native deposit of copper will pay re- 144 Rubber in Industry quires a great deal of time and the expenditure of a large amount of money. The system employed in mining varies as the percentage of copper to the ore necessary to mine for a given tonnage and the neglect of this precaution has caused several notable failures; expensive plants having been erected only to be later sold out at a loss. The mine shafts, where possible, follow the "dip" of the lode, thus avoiding the un- necessary mining of barren ground to reach the lode from the shaft as would be the case if the latter were vertical. Shafts are now placed a thousand feet or more apart and on the vertical sides of the shafts, "drifts" are run out along the lode from 85 to 150 feet apart; and from these shafts as starting points all of the lode matter possible is broken away and sent to the surface. Stamping. Crushed copper rock from the mine is taken to the "stamp mill" in center-dump tram cars. When the mill is reached the cars are run above the rock bins where they discharge directly into the bins above the "stamps." To save expense as many opera- tions as is possible are performed by gravity, but a constant effort is always made to introduce labor saving mechanical devices, both underground and on the sur- face. Among the devices adopted, it may here be noted, belt conveyors and elevators using Goodrich belts, occupy quite a prominent position. The function of the stamp mill is to crush the rock ore fine enough to make possible the separation of the copper from the mass. The rock runs over a feed pan from the bins into the "mortar" or bowl of the "stamp" or "hammer," into which a stream of water is also con- stantly flowing. Here the rock is crushed to a size small enough that it may be splashed through the 145 Rubber in Industry screens around the mortar. The larger lumps of copper are withdrawn from the bottom of the mortar through a tube against a small stream of water, which acts as a strainer preventing the lighter material from dis- charging with the copper. This method of discharging is called the hydraulic system and is utilized at several stages of the stamp mill process. There are many other operations in connection with the stamp mill but all of them are designed particularly for the purpose of separating the copper from the rock. After practically all the rock and other earthy matter have been separated from the copper it is sent to the smelter. Smelting. The product of the mine that goes direct to the smelter in mass often weighs several tons. The largest on record which was taken from the Minnesota mine in February 1857, was 45 feet long, 22 feet wide at the widest point, had a maximum thickness of eight feet, weighed about 420 tons, and was about 90 per cent pure copper. This "mass" copper together with the product of the stamp mill constitutes what is called "Mineral." The product of the stamp mill is not pure — the principal impurities found being "vein" rock, iron, silver, arsenic, traces of nickel and some others of the rarer minerals. The function of the smelter is to remove these impurities, and to leave the copper in a condition best fitted for the different uses to which it will be put — the principal of these being for electrical purposes such as wire, where great conductivity is required. The form in which it leaves the smelter is indicative of the use and when it is known that 7/100 of 1 per cent of arsenic in copper will reduce the conductivity of the latter 25 per cent, and that arsenic is almost always 146 Rubber in Industry present in copper ores, the necessity of careful refining will be appreciated. Upon reaching the smelter all mineral is treated first in a melting or a reverberatory furnace, the flame passing from the fire box over the copper under a low arched roof with a stream of air brought in from below. This is an oxidizing process and the slag that is thus caused to separate from the copper rises to the surface and is drawn off. After the removal of the slag, char- coal is thrown on top of the copper and a green hard- wood pole thrust into the metal the ignition of which results in the removal of the oxygen which has become mixed with the copper thus changing the action of the furnace from an oxidizing to a reducing process. If the reduction is overdone, the charge must be re-oxidized and again reduced. Thereupon, the copper is "ladled" or run out into molds in which it is formed into "Slabs" or "Anodes" for the electrolytic process. Electrolytic Refining. Copper derived from copper ores generally contains enough impurities to render it unfit for electrical purposes unless it is refined elec- trolytically. The impurities are of two kinds; first, ob- jectionable substances, such as arsenic, antimony, iron, etc., which reduce its conductivity; and second, small amounts of gold and silver which are desirable to re- cover, if possible. The impure copper which has been cast into slabs or anodes is now hung in large electrolytic tanks filled with a solution of copper sulphate. For each anode, a cathode, or thin sheet of pure copper, is placed in the tank between the alternate anodes, one wire of an electric circuit is attached to a slab or anode at one end of the tank, the other wire of the circuit is attached to the thin sheet or cathode at the other end 147 Rubber in Industry of the tank, the intermediate connections made, and a strong direct current of electricity is passed through the whole. As the current passes the anode is eaten away, the pure copper being deposited upon the cathode and the impurities settling as a slime to the bottom of the tank from whence they are removed from time to time and treated according to their value. The slime con- tains much gold and silver and the anodes may be en- closed in canvas bags which permit the free passage of the solution but catch the slime that falls. The cost of refining copper by this process is about 746 watts of current per hour for each 7 pounds of copper refined. "Pitch" The product of the tanks, in the shape of heavily deposited cathodes, is taken again to refining furnaces where it is melted down and brought to "pitch" — that is, to a purity of 99.88 per cent. Rolling Mills. The pure copper thus refined is melted and cast into "wire" bars, about 5 inches square and 5 feet long. In this form it is purchased by The B. F. Goodrich Company and sent to the rolling mills where it is rolled into round rods, about % mcn or tV inch in diameter, in which form it is coiled into bundles of convenient size and shipped to the Goodrich factory at Akron. The monthly average total of these ship- ments to our plant is now 500,000 pounds. Wire Drawing. The coiled copper rods as received by the factory are sent as called for to the "drawing" department where they are first pointed and then fitted into a series of chilled steel reducing dies by an expert known as the "die setter." He arranges the series, spacing them certain distances apart upon the rod to 148 Rubber in Industry correspond with the locations of the die holders on the drawing machinery. The copper rod with the dies properly set, is then placed in position on the ma- chinery, the several dies being securely clamped in their respective holders immersed in soapy water. Be- tween each there is a revolving spool or drum around which the rod is given a few turns in order to provide the necessary friction pull for drawing the rod through the various steps, reducing it little by little as it passes from the feed to the delivery end of the machine. Copper rod from the 34 or -^ inch original diameter as the case may be, is thus sometimes drawn by successive opera- tions (at least two, more often three) to a diameter as small as 1/1000 of an inch. Without the soapy water or some such cooling lubri- cant, it would be impossible, as may be imagined, to continue the wire drawing through its several steps with anywhere near like success. Even in spite of the constant stream of water and soap which is passing over the dies the heat generated by friction is such that the process tends to harden the copper thereby reducing considerably its conductivity. This undesirable charac- teristic is, however, easily counteracted by a subsequent step during which the wire, wound on metal drums, passes through a water sealed furnace where being sub- jected to heat and not air, it is thoroughly reannealed to a state of ductility suitable for electrical purposes. The rolls of wire enter this furnace on a slowly moving conveyor through water, leaving it on the same con- veyor through water, the mechanism of the apparatus being so constructed and speeded as to enable the process to go on continuously. The water jackets, of course, prevent oxidation. 149 Rubber in Industry Tinning. We are all conversant with the fact that sulphur is one of the principal ingredients in vulcanized rubber but a fact with which we may not be so familiar is that a reaction, which lessens the conductivity of wire, takes place between copper and sulphur, some of which is always present in a free state in every rubber compound. It is, therefore, necessary to separate the insulation from the bare copper wire and because no such action takes place between sulphur and tin we use this metal. If a wire is destined to be insulated with a rubber compound, therefore, it must first be put through an acid bath which thoroughly cleanses it and removes all grease, and is then run directly through a vat of molten tin, a thin coating of which adheres to the wire as it passes. Thus is the copper covered with a tin plating which prevents reaction between the copper and the free sulphur of the insulation. Wire Gauges. From what has been related in the preceding chapter, it must be apparent that when wire is to be installed to supply a few lamps or a small motor the required cross section area is naturally much less than if the installation were 100 or 1000 lamps or a 500 horse power motor. It is therefore a practical necessity to manufacture wire in various graduated sizes. These wire sizes are designated by numbers corresponding to certain wire gauges. It is unfortunate that there are in existence four or five such gauges; and that their grad- uations do not correspond nor their sizes vary in ac- cordance with any fixed rule. In this country the gauge in most common use is, however, the American wire gauge of the Brown and Sharpe Company. No. 1 wire on the B. and S. gauge is very nearly 3/10 150 Rubber in Industry of an inch in diameter, and the smallest wire, i.e., No. 40, is about 3/1000 of an inch. There are four sizes larger than No. 1, designated as 0, 00, 000, and 0000. The No. 10 wire on the B. & S. gauge is just about 1/10 of an inch in diameter and, if of copper, its resist- ance is about one ohm per 1000 feet. As a rule of thumb method, by subtracting three from the gauge number of any wire, we get the number of the wire whose cross sectional area is twice as great, as for ex- ample, the cross sectional area of No. 7 is twice that of No. 10. Circular Measure of Wire. Owing to the errors likely to occur from lack of agreement in the sizes of the various wire gauges, it is becoming more and more the custom among electricians to designate wires by their diameters expressed in thousandths of an inch, or mils. Indeed, by recent orders of the War Department, this has been made mandatory for our army. The area of cross section of a wire of one mil diameter is taken as the unit for area and called a circular mil. In re- ferring to wire sizes the standard of measurement, how- ever, must always be stated; as, for example, 100 feet of No. 8 B. &. S, meaning of course that it must be No. 8 according to the Brown and Sharpe Gauge. Stranded Wire. Wires larger than No. 0000 B. & S. Gauge, are seldom made solid, but are built up of a number of small units of the same size into a "strand"; the term wire being retained to designate the individual wires of the strand. Strands are usually built up of wires of such a size that the total is the same as would 151 Rubber in Industry be the cross section of a solid wire having the same gauge number. The stranding is done entirely by machinery, so ar- ranged as to apply a minimum pull and twist upon each separate wire and yet to form a compact cable. Too much twist has an injurious effect on the physical characteristics of the wire and inversely, not 'enough tension produces a poor cable. Certain well defined rules are followed in building up the cable. In other words, first one wire is used as the core, six wires being wound helically around it; the next layer consists of 12 wires, the third layer of 18 wires, and so on, each layer increasing in number by six. Should an extra flexible cable be desired, it is sometimes produced by twisting several smaller strands of wire together, later building these up by following the same rules of progression as were defined for the original stranding. The cabling or stranding machinery is composed of a series of revolving frames each somewhat resembling a Ferris wheel with the spools from which the wire is fed, representing the passenger cars. The wire itself does not revolve but rather the spools are made to rotate around a common center through which the wires pass, receiving the twist as each spool in turn passes entirely around the axle. This latter, i.e., axle is hollow and the core wire being fed from a drum placed at one end of the machine, passing through this hollow shaft, receives its first layer of wires as it leaves the first revolving rack. Additional strands, as many as desired, are applied in like manner as the cable pro- gresses from one rack of spools to another in the build- ing up process. 152 Rubber in Industry Copper Wire Table, Brown and Sharpe Gauge Resistance at 68° F. Size of Diameter Ohms per Feet per Pounds per wire inches foot ohm foot 0000 0.460 0.00004893 20,440 0.6405 000 0.4096 0.00006170 16,210 0.5080 00 0.3648 0.00007780 12,850 0.4028 0.3249 0.00009811 10,190 0.3195 1 0.2893 0.0001237 8,083 0.2533 2 0.2576 0.0001560 6,410 0.2009 3 0.2294 0.0001967 5,084 0.1593 4 0.2043 0.0002480 4,031 0.1264 5 0.1819 0.0003128 3,197 0.1002 6 0.1620 0.0003944 2,535 0.07946 7 0.1443 0.0004973 2,011 0.06302 8 0.1285 0.0006271 1,595 0.04998 9 0.1144 0.0007908 1,265 0.03963 10 0.1019 0.0009972 1,003 0.03143 11 0.09074 0.001257 795.3 0.02493 12 0.08081 0.001586 630.7 0.01977 13 0.07196 0.001999 500.1 0.01568 14 0.06408 0.002521 396.6 0.01243 15 0.05707 0.003179 314.5 0.009858 16 0.05082 0.004009 249.4 0.007818 17 0.04526 0.005055 197.8 0.006200 18 0.04030 0.006374 156.9 0.004917 19 0.03589 0.008038 124.4 0.003899 20 0.03196 0.01014 98.66 0.003092 21 0.02846 0.01278 78.24 0.002452 22 0.02535 0.01612 62.05 0.001945 23 0.02257 0.02032 49.21 0.001542 24 0.02010 0.02563 39.02 0.001223 25 0.01790 0.03231 30.95 0.0009699 26 0.01594 0.04075 24.54 0.0007692 27 0.01420 0.05138 19.46 0.0006100 28 0.01264 0.06479 15.43 0.0004837 29 0.01126 0.08170 12.24 0.0003836 30 0.01003 0.1030 9.71 0.0003042 153 CHAPTER TEN Insulation COPPER wire as employed for trolley, telegraph cir- cuits and many high tension (high voltage) trans- mission lines, supported in the air by glass, porcelain, or vitreous insulators, is usually left uncovered without even a coating of tin. For practically all other pur- poses, however, when the element of danger threatens life or property some form of insulation is necessary. Many materials, known as dielectrics, are used for in- sulation. Scientific investigation has arranged the prin- cipal non-conductors in a fixed series in order of their dielectric value. 1. Air. 6. Shellac. 11. Leather. 2. Glass. 7. Resin. 12. Porcelain. 3. Paraffin. 8. Silk. 13. Oils. 4. Mica. 9. Wool. 14. Slate. 5. (Vulcanized) Rubber 10. Paper. and Gutta Percha. The character of the insulation depends almost en- tirely upon the service in which the wire will be em- ployed. Telephone and annunciator cables and some distribution circuits employ paper, cloth and braided cotton singly or in various combinations. Although of stronger dielectric properties, for general use air (1), glass (2), paraffin (3), or mica (4), could not be employed to insulate a current bearing wire, therefore, practically all wires for lighting, power, automobile, telephone and 154 Rubber in Industry power plant circuits, submarine cables, etc., are insulated by rubber or its first cousin gutta percha. No. 5 then heads the list of practical insulating materials. Rubber. There are hundreds of grades of rubber and the use of each grade produces a different result. Realizing that the different grades are frequently almost indistinguishable, the importance of correct classification of crude rubber at the factory must be appreciated. Several carloads of the crude reach The B. F. Goodrich Company's Receiving Department every day. That part of each shipment which meets our insulated wire requirements is assigned to certain bins in a large cool, well protected rubber storage warehouse. Our selection and classification work is in the hand of a widely recog- nized crude rubber expert who personally examines each lot. Manufacturing. There are four principal types of insulated wire, but rubber-insulated is the most im- portant and the only type manufactured by The B. F. Goodrich Company. Since in the rubber-insulated it is rubber which acts as the non-conductor the quality of the compound is of special interest, for it must be capable of long service without cracking or hardening. Upon removal from the storage bins the rubber is washed, dried, compounded with sulphur and other in- gredients, milled, and sent to another storage room where it is aged a definite length of time. The charac- ter, experience and knowledge of the manufacturer are powerful factors in the intermediate processes — washing, drying, compounding, milling and ageing — that deter- mine, more than any other, the ultimate value of the 155 Rubber in Industry insulating material. Many "fillers" may be mixed with the rubber that unduly increase the weight and eventually destroy its dielectric value, thereby en- dangering life and property. To produce a good product, therefore, the inspectors, compounders and operators must be highly skilled, conscientious, and careful men; and the testing instruments and system must be so accurate as to eliminate the possibility of error. The preparation of the insulating material for "Goodrich" insulated wire conforms with our ideals of 50 years' development and the same steps in an enor- mous yearly production of tires, belting, hose and thousands of other rubber articles. We, therefore, need not describe these steps more minutely. After thoroughly aged or seasoned, this compound is either applied directly to the wire by the tubing or insulating machines through the dies of which the wire is guided; or is first calendered and cut into strips of the proper thickness and width, then applied to the wire and cables by the strip process machines. The tubing and the strip or sheet processes constitute the two methods by which the rubber insulation is generally applied to wire, but there are many different compounds and thicknesses of rubber employed to meet various requirements. For instance, in automobile ignition wiring and storage battery feeder cables, special oil and acid resisting compounds must be used to meet the deteriorating effect of oils and acids upon rubber. The tubing machine method is employed principally on the smaller sizes of wire. By this method the com- pound is forced by the revolving worm through a die, surrounding the conductor with compound; the thick- ness of the wall being determined by the size of the 156 Rubber in Industry opening in the die. By this process the insulation is delivered without seams and in a homogeneous layer. By the strip process, which is more suitable for the larger wires and cables, the rubber wall is formed by folding one or two strips of compound around the con- ductor. Small wheels are engaged against the side of the cable which bind the edges of the strips together so effectively that, after vulcanization, the seams are as strong as other parts of the wall. Regardless, however, of the method the rubber com- pound is in a soft plastic condition and must be vulcan- ized to make it firm, elastic, permanent and enduring. Vulcanization is an essential feature in the manufacture of insulated wire and requires very careful attention, i.e., the duration of the treatment and the pressure used determine in a great measure the character of the finished product. A large percentage of the insulated wire which we produce goes directly from the insulating machinery to the vulcanizers. Some, however, es- pecially the larger cables, require reinforcement, ac- complished by winding upon it a layer or layers of tape which preserve the cylindrical form and prevent me- chanical injury of the still plastic insulation. In this connection we will explain that the tape once applied over the insulation is very seldom removed after the vulcanizing process is completed. In order that all parts of the rubber insulating walls may be subjected to a uniform temperature and pressure, the wire is wound on large drums or coiled spirally in circular pans. The live steam is therefore able to transmit its heat evenly to the whole surface of the insulation. Underwriter's Code. To insure that the public will be supplied with a quality which may be known as safe 157 Rubber in Industry for wiring buildings and for other general purposes, the National Association of Fire Underwriters has fixed cer- tain requirements that manufacturers must meet in order to offer a product approved by its Electrical Com- mittee; or which will be permitted to be used in all buildings upon which insurance is effective or may be written. These requirements are exacting; specifying among other things the quantity of rubber which must be contained in the insulation compound, and in order to avoid friction with the National Board, great care must be exercised in all manufacturing steps and at a considerable expense. These stringent requirements, however, not only protect the ultimate consumer but also react to the advantage of that class of manufac- turers of which The B. F. Goodrich Company is repre- sentative. In order to make their rulings effective the underwriters maintain a force of inspectors Who operate in conjunction with the testing laboratory at Chicago; i.e., these inspectors visit the wire manufacturer fre- quently and pick at random, from stock, samples to be tested. Furthermore, since it is required that the product of each manufacturer be distinctively marked, a piece or roll of wire may be taken from the stock of any jobber, dealer, or from an electrical contractor's job, sent to Chicago and subjected to the prescribed tests. In other words, the Underwriters may buy a roll or piece of wire anywhere and at any time and upon examination determine whose product it is. If the piece fails to pass even one phase of the test such failure is counted as a demerit against the manufacturer and the reader may be assured that the results of these tests are carefully recorded. Ten failures within any given six months result in the manufacturing privilege 158 Rubber in Industry with the approval of the National Board of Fire Un- derwriters, being withdrawn. The B. F. Goodrich Company is one of a group of six out of about thirty-five insulated wire manufacturers in the United States, who for the years 1915, 1916, 1917 and 1918 have enjoyed the distinction of not having a single demerit recorded against them. In fact the basic principles of quality of this company as applied to other products are here so strongly reflected that even in our cheapest grade, tests are nearly 100 per cent above the Underwriters' require- ments. Plain Rubber Covered. Although most insulated wire such as lamp and telephone cord, National Code inside and outside wire, etc., with which the lay public is more or less familiar, is generally finished over the in- sulation with a braided fabric jacket, either of cotton or silk, nevertheless, a large part of the wire sold es- pecially for installations where it may come in contact with acids or other agencies destructive to the fabric type of cover, is supplied only with a tough rubber casing or cover. As an instance where this is true we point to electric cable as used for the conveying of power to drills, etc., in mining service where the most severe conditions imaginable are met with. These cables are being constantly pulled over timber, rough floors and sharp rocks, bruised by falling rock, coal or ore and pinched by car wheels. Furthermore, mining cable is subjected to unusual wear by being wound onto and unwound from the carrying drums at frequent in- tervals and in spite of the care exercised by wire man- ufacturers generally in the construction of this service type the average life of mining cable prior to the intro- duction of the "Goodrich Standard Concentric" was but 159 Rubber in Industry two months. Today, however, we are constantly re- ceiving reports from large mines all over the world of a service of six, seven, and eight months' duration. "Goodrich Standard Concentric Mining Cable" is constructed by first insulating with rubber compound a very flexible stranded cable over which layer of rubber compound a frictioned fabric tape and braided fabric cover are next applied successively. Over this, the second conductor, composed of many wires, is applied helically, the whole then being covered with a tough, wear-resisting compound. To this description, we wish to add by way of explanation, a mention of the fact tlat after each layer of compound is applied to the cable a cure is effected, either on drums or in trays as previously described. Fabric Covered Wire. In addition to the plain, rub- ber-coverd type, considerable insulated wire is finished with a braided fabric cover or a combination cover of woven and braided fabric. When rubber impregnated woven fabric is used, such is always applied in tape form, being wound over the insulation in a helix with slightly overlapping edges. Should a second ply be re- quired this is wound over the first in like manner but in the contrary direction. No individual conductors protected with woven fabric covers alone are employed except when constituting a part of multiple conductor cable. This type is further protected over all by braided fabric jackets or lead sheathing. Braided fabric jackets are those which are constructed in tubular form directly over the insulation by the standard type of braiding machinery the same as employed in the construction of braided construction hose. As has been pointed out before this machine consists of a series of bobbins which 160 Rubber in Industry travel in an irregular circular path entwining the threads after the same manner in which a Maypole is wound, the wire in this case being the pole. Both cotton and silk are used in covering wire, the choice of material depending upon the service for which the finished product is desired, but the size of the thread and the number of bobbins employed must be deter- mined by the diameter of the conductor. This is to say, the larger the wire or cable the greater the number of bobbins and the coarser the thread. Beautiful variegated patterns or the underwriter's color scheme specifications for each manufacturer are secured by the employment of thread of contrasting colors, arranging the bobbins containing the different colors according to the pattern desired. Cotton covers either braided or taped, when exposed alternately to heat and moisture, that is, sunshine and rain, will deteriorate rapidly and therefore it is essential in order to preserve such coverings that they be treated with a moisture-proof compound. The Goodrich Com- pany uses for this purpose a special bituminous waxy preparation which thoroughly saturates the fabric cover, thereby rendering it waterproof. This is applied by passing the covered wires or cables through tanks where the wax is heated to liquid form. The surface is then polished by passing the wire or cable through a series of dies revolving rapidly in opposite directions. The compound which we use for proofing cotton covered wire, we may add, is distinctively Goodrich one par- ticular characteristic being that it will not stain the hands with a sticky, tarry substance as is so often the case with this type of wire. To this statement elec- tricians will testify. 161 Rubber in Industry Multiple Conductors. Gables composed of two or more individual conductors are frequently employed in sys- tems where many instruments are connected with one switchboard or similar device, as for example, in fire alarm, telegraph, and telephone service. These con- ductors may be separated from each other merely by a plain rubber insulation or may have in addition to the rubber insulation either a braided fabric taped jacket. There are many possible combinations in multiple con- ductors, but when two conductors only are desired, these are generally placed parallel both being encased in a braided fabric jacket. However, when three or more units are combined in one cable they are twisted together and one or more jackets braided over the whole construction. Cotton or jute filler is sometimes twisted in with the several units in order to fill up the spaces between them and to give the finished cable a smooth cylindrical appearance. To prevent error in "cable splicing" or in making con- nections to distributing racks without the necessity of employing testing devices each unit or pair in a multi- ple conductor cable, as the case may be, is usually covered with a braided jacket of distinctive coloring or color combination pattern after the manner described under the previous caption, Fabric Covered Wire. As will be recognized, this ingenious idea greatly facilitates the work of making a large number of connections where new cable is being installed. It is sometimes desirable that these fabric jackets be treated with a moisture-proof compound the same as wire employed in outside work, and at the same time not having the color contrasts destroyed as it would by the use of the black waterproof preparation. In such 162 Rubber in Industry instances a semi-transparent solution is used thus per- mitting the ready identification of the various wires or pairs and yet having the desired effect. The prepara- tion which we employ in this process is a characteristic- ally Goodrich formula and one which has proven to be a valuable asset particularly in the manufacture of automobile starting and lighting cable, telephone cable, etc. Where either single wire or multiple conductor cable with woven jacket covers is to be exposed to any con- siderable heat such as around drying machinery or in steel mills or where the fire hazard is particularly great the fabric covering is made fireproof either by the use of a fireproof paint or by asbestos fiber jackets, the choice depending upon installation conditions. Lead Covered Cable. It is frequently essential for tele- phone, telegraph, and even power and lighting cable, both for underground and aerial installations to be en- cased in a sheathing of lead. This type of electric con- ductor is not, however, as is often supposed, made by pulling the cable through a lead tube but on the con- trary, by forming the lead cover over the cable much after the same manner in which the outside rubber cover is applied to braided construction hose. In other words, the insulated wire or cable to be covered is passed through a machine receiving its sheathing of lead as it issues, a die governing the thickness and size. This machine is very similar to the one commonly employed in the manufacture of lead piping, being an enormously heavy combination furnace and force pump in which the lead is reduced to a flux and thereby forced out through the die over the cable by powerful hydraulic plungers which exert a constant pressure keeping 163 Rubber in Industry the wall thickness of the sheathing uniform. The mechanism of this machine is so arranged and con- structed that the lead coating is barely hot as it issues from the die, thereby doing no damage to the insulation or fabric covering underneath, besides being easily handled as it comes away from the die. Tests. Immediately following the vulcanization of all Goodrich rubber insulated wire two distinct electrical tests are made which most manufacturers, preferring to wait until the product has been finished, omit. Ex- perience, however, has demonstrated to us that these tests are responsible for a product nearer perfect than would otherwise be possible to maintain. The first of these tests is made to insure against leaks occurring in the insulation. Several hundred feet of wire in coils or bundles is immersed in a tank of water, all except the ends which are connected in multiple to the terminals of a high voltage circuit. After having remained under water for a certain length of time, the current is turned on and should there be a defect in the rubber wall, the soaking it receives will have made a path through which the high voltage current can escape. Thus, wherever the insulation has broken down, flashes or sparks will be observed springing from the surface of the wire. These spots are marked by the inspector and each coil, bundle, or single piece of wire containing even one leak, is rejected by him as imperfect and returned to the insulating department. Fortunately, leaks of this character may nearly always be repaired by simply replacing a section of the rubber insulation and vulcan- izing the patch built in on a small electric heater. All wire, however, after being repaired in this manner must again undergo the test. 164 Rubber in Industry The second test mentioned is conducted in order to determine the dielectric strength of the insulating com- pound and should the result of this test show any piece to fall below our standard, the whole coil will be re- jected as faulty and a subsequent investigation made in order to discover whether the weak resistance to the passage of current is due to low quality of ingredients used in the compound, under-milling of the compound, gritholes, or any one of several factors which might cause an insulation of low dielectric strength to be pro- duced. This test is made in a similar manner to the one previously described. Final tests according to the National Association of Fire Underwriters' requirements are also made after the wire or cable has been completed and is otherwise ready for shipment. These tests are of various kinds but made principally to determine electric and physical strengths of the insulation and a permanent record is kept in our factory office of the test of each coil, bundle, or piece of wire or cable produced, these being filled under serial numbers to correspond with numbers ap- pearing upon the tags attached to each bundle of wire. This system enables us to check up complaints should it be claimed that any particular shipment of ours had failed to meet the Underwriters' specifications. We are able immediately to turn to our records and secure a complete history of the tests made. Small conductors are shipped in bundles wrapped in paper tape to exclude light and dirt. Large conductors are wound on wooden reels, covered with paper and boxed in. Automatic devices are employed for coiling and wrapping, thus carrying out to the very last, prac- tices of economy in manufacture through the use of 165 Rubber in Industry which the savings in up-to-date production may be passed along to the ultimate consumer and thus the use of insulated wire be extended into every possible field. The Use of Insulated Wire. The duties of in- sulated wires are numerous and diversified; in fact, so multitudinous are the places where this product of the rubber factory plays a most vital part that a consider- able thesis might be prepared upon this subject alone. We, however, have not here the space to fully treat this phase of the wire question, if indeed a complete dis- cussion would be of value in a text of this kind; and accordingly, must confine ourselves to a mere outline of the topic leaving its development for further study and investigation on the part of our readers. To best exemplify our first statement, however, we may mention that rubber insulated wire forms an im- portant part of the construction of all modern buildings, is essential for starting and lighting systems of auto- mobiles, is indispensable to the safe operations of trains both within and without for the illumination of the coaches, for lighting the track ahead of the locomotive, and for the operation of the signals which guide the engineer safely over the maze of tracks and switches. Telephone, telegraph, and fire alarm systems are almost wholly dependent upon rubber insulated wire; the electric automobile would be useless without it and the conduction of high and low tension current for power purposes could not be accomplished without the use of some rubber insulated wire. Both mines and mills de- pend upon this useful article and the street car which transports the workman to and fro between their homes and the factories could not be operated if the electric cur- 166 Rubber in Industry rent could not enter the controller over protected con- ductors, while the army, the navy, and the merchant marine would today be hopelessly unable to cope with modern conditions of warfare and commerce without this very vital product. To better illustrate these assertions, we may mention that industry which interests The B. F. Goodrich Com- pany from so many standpoints, viz., the building of automobiles. This compact modern transportation unit which today is playing such an important part in our national and international life, would be useless without rubber insulated wire and although when compared to other items of rubber which enter into the construction of the automobile, wire in dollars and cents represents an infinitesimal outlay, it plays such an important part that its failure to deliver the service expected is of greater moment than even the performance of the rub- ber tires which all know to be indispensable. In other words, if the insulated electric wire does not properly conduct the current so as to explode the fuel charge in the cylinder of the gasoline driven car, or if it does not properly link the storage battery to the motor of an electric, all the tires in the world will not suffice to make these vehicles useful, for without "juice" they most surely must stand in their tracks until disintegration complete its work. Today the home without its electric lights, electric flatirons and vacuum cleaner attachments, seems to us to represent a page from the "Dark Ages;" the office without its telephone, its electrically driven adding ma- chine, multigraphing and tabulating devices, a decrepit institution and the community without its telephone and fire alarm system, a dismal if not dangerous place 167 Rubber in Industry in which to live. Thus we might continue through page after page of illustration, each portraying the ex- tent to which modern life is dependent upon insulated wire, particularly that of the rubber insulated type. 168 CHAPTER ELEVEN Marketing (Insulated Wire) SELLING. On the North American Continent today are some forty odd manufacturers of rubber insu- lated wire, about thirty-five of whom are located in the United States, where in addition to ourselves, there are approximately ten important manufacturers, that is, those who turn out a diversified high grade product. Considerable volume is, however, sold by the smaller companies, but many of these while marketing an extremely large footage, confine their output to the smaller sizes. As may be imagined, therefore, a diversity of selling methods exists, the policies of the different manufacturers necessarily varying according to the product, the volume of output, and the ideas of those in charge. Goodrich wire is marketed through an organization composed of men concerned solely with this one division of our output and who devote their whole time to selling this product. Channels of Distribution. The distribution of in- sulated wire from the Goodrich plant to the ultimate consumer is not accomplished through any set channel, but rather done according to the method which may be deemed best suited to the particular conditions of place, or division of product to be marketed. In other words, our distribution is accomplished partially through the 169 Rubber in Industry jobber, partially through the dealer, but frequently to the ultimate consumer direct. Why insulated wire must be so handled will be apparent when we call atten- tion to its wide diversity of uses. But told in other words, insulated wire is used in the lighting systems of buildings could not be sold to the consumer direct with economy, and therefore must be distributed either through the jobber, dealer, or electrical contractor, and since the jobber offers the most logical medium through which to distribute this item, he, in most cases, is em- ployed. On the other hand, signal cable, submarine cable, generator cable or telephone cable can better be sold direct to the users of such wires or to the manufacturers of electrical devices, while automobile starting and lighting cable, on account of the special specifications to be met, must be sold to the consumer, i.e., manufacturer of automobiles. Therefore, those traveling in the in- terest of insulated wire sales must visit all classes of trade, such as jobbers and dealers in wire and electrical goods, steam and electric railroads, automobile manu- facturers, telephone and telegraph companies, manu- facturers of fire alarm systems, municipalities, archi- tects, etc. In some instances it may be wise for us to give exclusive selling territories to the jobbing trade for certain items of our line, whereas, under other con- ditions it may be best to secure the business on an open market basis. This paragraph, however, must not be taken as a declaration of Goodrich selling policies but merely as an indication showing the methods which we must ordinarily employ in the distribution of our insulated wire output. 170 Rubber in Industry Branch Stocks. In certain sections of the country where industrial conditions demand such an arrange- ment, in order to facilitate deliveries, our established branches carry in stock such items of the insulated wire line as have been found most in demand by the industries located in their respective territories. The advantages to the trade and consumer of having such local sources of supply from which quick deliveries may be made, will be readily apparent to our readers and we, therefore, need dwell upon the subject no further than to mention that such stocks permit the filling of orders with the least possible delay. It is our intent to have these stocks complete enough at all times to fill every reasonable immediate shipment order. The branches which at present are carrying stocks of insulated wire are New York, Detroit, and Chicago. These are assigned a definitely bounded terri- tory which they serve and the balance of the country is served direct by Akron. 171 Rubber in Industry Conclusion. It is a strange coincidence that two factors — electricity and rubber — about the exact nature of which so little is known, should be closely associated in the production of a common commodity — insulated wire. As the scientists Gray, Volta, Ohm, Henry, Faraday, Edison and Westinghouse analyzed the con- ditions governing the manifestations of electricity and developed means for making its force useful; so did Peal, Macintosh, Priestly, Goodyear, and Goodrich apply themselves to the problem of converting the soft unstable crude rubber into the enduring form in which it now so satisfactorily meets the requirements of the civilized world. The high quality of the Goodrich prod- uct entitles our wire to its excellent reputation, and also justifies the share which we possess in the leader- ship of the industry. 172 Review Questions Belting, Hose, Molded Goods, Packing, Mats, Tiling, and Miscellaneous Mechanical Rubber Items PREFACE 1. In a general way, what articles are included under Mechanical Goods? 2. What article was the first production of the Good- rich Company and how branded? 3. Name the divisions of Mechanical Goods which we employ in factory and sales activities. CHAPTER ONE 1 . Discuss briefly the history of belting showing why rubber belting entered the field. 2. Describe the construction of a rubber belt, giving special attention to vulcanization. 3. Why do we market several brands of transmission belts? 4. Name and describe three types of Rubber Trans- mission Belts. 5. Discuss troughing qualities, cover and edges of our Conveyor Belts. 6. Describe the step-ply construction as sometimes used in Conveyor Belt construction, showing its disadvantage. 7. Name at least two belts which we offer for special work. 173 Rubber in Industry 8. What characteristics must Elevator Belt construc- tion include and why? CHAPTER TWO 1. Give a brief history of hose. 2. Describe the Wrapped Duck construction Hose. 3. What are the features of Braided Reel Hose that explain its rapid acceptance by users? 4. Compare or contrast the building up of Woven and Braided Hose. 5. Discuss the types and application of Protective Cov- erings. 6. Explain the difference between Water and Garden Hose. 7. What is the chief difficulty to overcome when con- structing Steam Hose? 8. Name at least five uses for hose which require special constructions. 9. Tell in 100 words why we may be termed Hose Specialists. CHAPTER THREE 1. Where and by whom were the first molds used to make rubber articles? 2. What products, generally speaking, are included under Molded and Lathe-Cut Goods? 3. Describe the steps in the construction of any molded article. 4. Why do we ourselves make nearly all the molds used in our Molded Department? h. What rank do we hold in Valve Manufacture and why? 174 Rubber in Industry 6. What is meant by Spring Rubber and where is it used? 7. Describe at least three different styles used in the construction of Billiard Cushions? 8. Is "Textan" a rubber sole? Explain. 9. Write a paragraph on "Molded and Lathe-Cut Goods Constitute the Made-to-Order Department of Rubber Manufacture." CHAPTER FOUR 1. Describe the use of packing. 2. Give a short synopsis of packing evolution. 3. How is sheet packing manufactured? 4. Define: — Sheet Packing, Hydraulic Packing, and Spiral Packing. o. How is Hydraulic Packing made? 6. Why is cloth sometimes placed in Sheet Packing? 7. What do we use for lubricating packing and for what purpose is this substance applied? 8. What special features do we sometimes employ in Sheet Packing constructions? 9. Do we consider our present lineup of Packings the "last word" in this field? 10. When excessive oil is present, what Packing do we recommend? CHAPTER FIVE What characteristics has rubber to warrant its ap- plication as a flooring or floor covering? 2. Give a few of the more common uses for Perforated Mats. 3. Describe the construction of a Perforated Mat. 175 Rubber in Industry 4. Compare or contrast Perforated Mats and Solid Matting. 5. Discuss Fabric Insertion in Solid Matting. 6. Name at least three special solid mats we offer. 7. Where has Interlocking Tiling found its chief appli- cation? 8. Describe construction of Interlocking Tiling. 9. How do we recommend the laying of our Inter- locking Tiling? 10. Describe the construction and appearance of our Inlaid Tiling. CHAPTER SIX 1. What articles constitute the miscellaneous group? 2. Who invented Rubber Thread and why? 3. Name three or more present day uses for Rubber Thread. 4. Describe how we make Rubber Thread. 5. Our Rubber Rolls are used chiefly in connection with what appliances? 6. How do we make rolls? 7. Describe the building up of a Deckle Strap and show the advantage of our method. 8. Where is Glazing Rubber used? 9. Are the places for the use of Channel Rubber de- creasing? Explain your answer. CHAPTER SEVEN 1. Through what mediums do Mechanical Goods rep- resentatives market our products? 2. Explain fully what connection a salesman traveling in Chicago territory has with the head of Me- chanical Sales at Akron. 176 Rubber in Industry 3. Where are stocks of Mechanical Goods maintained and why? 4. What protection does a buyer have when selecting an article manufactured in our factory? REVIEW QUESTIONS Insulated Wire CHAPTER EIGHT 1. What is polarity? 2. What is the relationship between magnetism and electricity? 3. What commercial apparatus is based on the dis- coveries of Henry and Faraday? 4. Name the two sources from which current elec- tricity may be derived. Which is the more im- portant and why? 5. Describe in your own words, the principles of: — the battery cell; the dynamo or generator. 6. What is meant by the terms: — direct current; al- ternating current; circuit; volt; ampere; resistance; watt; kilowatt? 7. Why do most of the greater transmission lines transmit alternating current only? 8. What is the difference between a primary battery and a storage battery? 9. Name the two principal types of storage batteries and differentiate between them. 10. Who discovered that electricity may be conducted from one point to another? How? 177 Rubber in Industry CHAPTER NINE 1. Name the six best conductors of electricity. 2. State why copper is more generally employed than any of the other five and describe its advantages over the others, individually. 3. Whose discoveries and inventions lead to the present enormous demand for insulated wire? 4. Why are two wires necessary in connecting up lamps, motors or any other electrical devices? 5. Name our principal copper producing states and mention four mines. 6. Where and when was the first copper mine opened in the United States? 7. Explain the principal step in the process of obtain- ing copper wire bars from the earth. 8. Describe electrolytic refining. 9. Explain the various processes employed to convert the wire bars into finely graduated wire ready to be insulated. 10. Which is the larger; a number wire or a number 10 wire? CHAPTER TEN 1. What is the name of the principal wire gauge used in this country, and who is it manufactured by? 2. What is the size of a wire whose cross-sectional area and conductivity is twice as great as a num- ber 10 wire? State the rule. 3. What is meant by a circular mil? 4. Why is stranded wire used instead of solid wire in the manufacture of large cables? 178 Rubber in Industry 5. What is the best insulator or dielectric? Name four which have greater dielectric value than vul- canized rubber and compare each with vulcanized rubber. 6. What is the most important ingredient which is used with rubber in the manufacture of insulating material? 7. Why is it necessary to "tin" the wire before apply- ing rubber insulation? 8. What properties should a good insulator (non- conductor) embody? 9. Describe the processes which are employed in the application of the insulation to the wire and explain the various tests that are employed in the. manu- facture of "Goodrich" Insulated Wire. 10. In multiple conductor cables, why are different color combinations used in braiding the various wires which go to make up the cable? CHAPTER ELEVEN 1. What is meant by the Underwriters' Code? 2. Describe the inspection methods of the Fire Under- writers. 3. How does the inspector identify the manufacturer of a piece of wire when it bears no label? 4. Explain the effect of the inspections on the manu- facturer. 5. Explain a particular distinction which The B. F. Goodrich Company enjoys among the wire manu- facturers. 6. Describe the different methods of marketing wire. 7. Give an outline of your idea of a better insulated wire selling plan. 179 Rubber Industry 8. When and by whom was The B. F. Goodrich Com- pany organized? 9. Tell as much of the history and development of the company as you can. 10. What do you think of the future of the Rubber In- dustry? 180 LIBRARY OF CONGRESS illlilflMIlllin O 018 376 590 5 • M ■ Ah