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THE INDIA RUBBER WORLD 



[Seitember 1, 1920. 



Will Rubber Soles Successfully Replace Leather Soles? 



A Discussion of Rubber and Fiberized Soles from New as Well as Old Angles. 



B\ Chester C. Burnliam. 



MORE ANn MORE am I convinced that the day is approaching 

 wlicn a material composed mainly of rubber and some fiber 

 is going to be in quite general demand for the soles of 

 shoes. Rubber manufacturers have made remarkable progress 

 in the manufacture of fiberized soles during the past five years 

 and it is interesting to note that progress and success seems to 

 have been greatest with those who have studied the problems :d 

 product and market in the most thorough manner. 



There is a profound need for intensive study of the subject 

 of fiberized soles. It is a fact, which even a slight investigation 

 will substantiate, that much of the "grief" experienced by early 

 promoters of so-called "substitutes for leather" was brought upon 

 themselves by an appalling lack of knowledge concerning the 

 uses of the product they marketed. Millions of dollars for mold 

 equipment and advertising were thrown away in a short time 

 through snap judgments and short-sighted policies. 



During the war, when sole leather prices went sky high, the 

 fiber sole should have come into its own. By that, I mean to 



Doited Likes 



Show Old 



Pattesn. 



PIG 3- 



Stages of Sh 

 Mold Design. 



say that economic conditions at that time were decidedly favor- 

 able to its introduction and sale in a large way. Unfortunately, 

 obstacles were encountered, and in overcoming them at the start 

 much was done to improve the product, but the expected heavy 

 demands were not realized. How long it may take to regain 

 this lost advantage is uncertain, but with the cattle supply of the 

 entire world decreasing and with our domestic production of 

 hides for sole leather falling off in an alarming manner, there 

 is no question about there being a place for all the leather we 

 can produce and also for a vast quantity of satisfactory fiberi/ed 

 rubber soles. 



DEFECTS OF EARLY TYPES. 

 It is not difficult to recall the very earliest rubber soles that 

 were manufactured. Some of us may not be altogether proud of 

 them now, but we are prepared to admit that they were nearly 

 all heavy, poorly designed for shoe factory manipulation and 

 often composed of very little rubber and very many adulterants. 

 Some you recall, had a very pungent odor which penetrated the 

 insoles of the shoes and even the hose of the wearer and made 

 frequent foot baths necessary. Be that as it may, their sale was 

 large and on a type of foot-wear classified as "vacation suoes." 

 Purchasers of this sort of footwear honestly expected the soles 

 to crack across the ball or break away at the toe stitching long 

 before the soles were worn through and often before the end of 

 a short vacation season. 



It is no wonder thiii, that purchasers often wished for some 

 sort of a rubber sole that would at least last the season through 

 and in addition, furnish a clinging, flexible and waterproof sole 

 the while. It must not be forgotten that this vacation footwear 

 was exceedingly popular with many people as was attested by 

 the enormous sales in spite of unreasonable wearing qualities. It 

 was common for a shoe clerk to suggest to a complaining cus- 

 tomer, the advisability of resoling the shoes with leather, altiiough 

 the shoes may not have been a month out of that store and in- 

 variably, such shoes were sold without a guaranty for reasonable 

 wear of the soles. 



With rubber soles possessing many known deficiencies and vet 

 with an unlimited market in sight and only awaiting development, 

 it is strange that the rubber manufacturers did not pay more 

 heed to improving their products. That there was need for im- 

 provement is shown by the accompanying diagrams and even 

 these changes were not thought desirable until after the appear- 

 ance of fiberized soles. Had the fiberized product not been 

 thought of, it is possible that we might yet be trying to market 

 the old style soles and with the same lack of attention to the 

 requirements of the trade. 



But with the introduction of these new products, new uses 

 were found for them and in responding to these new uses a 

 closer study of the use and abuse of soles in the manufacturing 

 as well as in the wearing of shoes was made. 



Over night, as it were, rubber manufacturers came to realize 

 that their rubber soles had offered many perplexing problems 

 to the shoe manufacturer because of their varied mold styles. 

 The early style molds resembled the dotted line diagram in Fig. 

 1. while the standard pattern which soon came into general use, 

 resembled more closely the solid line pattern shown in the same 

 figure. The soles had to be "rough-rounded" or rough trimmed, 

 anyhow, and whereas there might be a slight waste in some pat- 

 terns the waste was more than offset by the time saved in shift- 

 ing molds in the press room, by the gain in production and by 

 the ease for all parties to handle their stock room problems. 



STANDARDIZED PATTERNS AND IMPROVED MOLDS. 



The standardized patterns popularized themselves so quickly 

 that no one thought to improve them further and thus other de- 

 fects passed into the new mold equipment without notice. It 

 had been thought necessary to have a sharp bevel or pitch to the 

 breast of the sole at the point where the forepart thinned out 

 into the shank. The thread on the sole stitching machines often 

 broke when the machine presser foot came to these sharp rises 

 or when it jumped off into space, and at other times the thread 

 tension increased so suddenly that the soles were entirely cut 

 through as one cuts cheese with a thread. 



The first attempt to correct this trouble was in the line of 

 lengthening this bevel. This was better, but trouble was still 

 experienced when the presser-foot of the sole-stitching machine 

 tried to climb up this pitch on one side and down on the other. 

 No very satisfactory results were obtained until some one hit on 

 the idea of making the "fadeaway" or undulating shank. With 

 this type, the presser-foot gained and lost the tension gradually 

 and allowed the automatic thread-controlling tension devices 

 to operate properly. 



Even with this improved mold the troubles were not ended, 

 for it was soon found that when soles with heavy foreparts were 

 attached to certain types of shoes, the shanks were often not 

 heavy enough to stand the strain of the stitching and wearing 



