900 



THE INDIA RUBBER WORLD 



September I. 1921 



of convenient size and is easily cut to suit the requirements of 

 use. In practice the mold board is cut large enough to afford 

 a liberal margin around the impression of the type-form to 

 strengthen the mold. To make a mold, the mold-board mounted 

 on an iron pallet, shown in Fig. 1. is dusted with talc and pressed 



face downward against the type- 

 face, ali!o dusted with talc. 

 Under usual conditions the full 

 depth mold can be obtained at 

 the first impression in the hand- 

 press. If a deep mold is required, 

 the matri.x compound is better 

 than the mold-board. In damp 

 weather the use of naphtha 

 is used on the t\-pe-face to 

 prevent the mold-board stick- 

 ing. To free the mold from 

 the type, tap the bottom of the 

 pallet or type-form on the 

 press-bed. An attempt to pull 

 the mold from the type invari- 

 ably results in breakage of the 

 mold. Fig. 2 shows type and mold-board impression. 



STAMP GUM 



There are several varieties and qualities of stamp gum suited 

 to rubber-stamp making. Unvulcanized sheet gum for rubber 

 stamp work is calendered 1/16-inch thick and applied to holland 

 cloth which preserves a high gloss surface on the gum and 

 allows the material to be conveniently handled and cut to size. 

 The usual cure for this gum is ten minutes at 60 pounds of 

 steam (307 degrees P.). 



For the ordinary run of hand stamps a cheaper grade, put up 

 in similar fashion, is furnished, curing in eight minutes at 80 

 pounds of steam (323 degrees F.). A hard curing gum, calen- 

 dered 1/16-inch thick and applied to holland cloth, is made for 



Ihe Be 

 Fig. 



:.^: V'c. Co.. N. Y. 



2. Type Tie-up 



MoLD-Bo.^RD 



making hard rubber stereotyiK; printing plates. It cures in ten 

 minutes at 80 pounds of steam (323 degrees F.). 



Rubber type are made from semi-cured rubber 7/16-inch 

 thick. It is inferior in grade to either of those mentioned above 

 and cures in ten minutes at 60 pounds of steam (307 degrees F.). 



Rubber stamps are frcc|ucntly mounted on sponge rubber back- 

 ing to secure good impressions on uneven printing surfaces. 

 Backing stock of this sort is sold to the stamp manufacturer in 

 cured slabs 20 by 20 inches in thickness of 14, 3/16 and J4-inch. 



CURING RUBBER STAMPS 



The method of curing stamps in open-steam vulcanizers is 

 superseded by curing in a press. The latest form of this method 



is by utilizing elec- 

 tricity for heat- 

 ing the press plat- 

 ens, and is shown 

 m Fig. 3. Fitted 

 on the interior of 

 these press-plates 

 are a number of 

 thin metal electric 

 resistance plates 

 or space heaters. 

 These distribute 

 the heat by con- 

 tact through the 

 faces of the plat- 

 ens and supply the 

 temperature for 

 curing stamps. 

 Owing to the 

 ribbed construction 

 of the upper side 

 of the top vulcan- 

 izing plate and the under side of the lower plate, the press re- 

 mains cool and can be used at all times for making molds. 



The Barton Mfg. Co., N. Y. 



Fig. 3. Electric Rubber Stamp Vul- 

 canizing Press 



Rubber -Set Fur, or "Artificial Fur" 



A New Product Indicated by the Nowell Process 



THAT both rubber and gutta percha are used in the man- 

 ufacture of tine furs is well known. The use of the former 

 is indicated when pointed furs are produced, that is, when 

 the long hairs that give value to a skin are set into the shorter 

 ■ones and kept in place by thin cemented cuts. The use of gutta 

 percha in the form of tissue is for a backing when bits and scraps 

 of fur are brought together to form whole skins. 



The manufacture of fur by the yard is, however, a long step 

 ahead of the work mentioned. To begin with, fur is warm and 

 ■of value chiefly because of the presence of two types of hair, 

 the fur itself with hairs short, downy, and barbed longitudinally, 

 and the over-hair, which is straight, long and stiff. The over- 

 hair keeps the fur from matting and thus makes it of value 

 for wear. A machine that can build up hairs, both fur and 

 •over-hair, and in its ultimate development copy any kind of 

 fur, from squirrel to sable, is indicated by the Nowell invention. 

 A description of the new machine and process follows : 



The apparatus consists essentially of a stand supporting a heat- 

 ing device, using electric coils or steam — indicated as (g) in 

 the accompanying diagram — and a vulcanizer marked (ib), also 

 •using either of the forms of heat mentioned. Over both of these 

 tinits passes a strip from a roll of duck or other sheet-form 

 material (b) to be fur-coated and wound upon another roll (d). 

 As the fabric passes over the first idle roller (c) it receives across 



its entire face through the flattened spout (f) a coating of 

 creamy consistency of waterproof adhesive substance, as rubber- 

 base cement, from the container (<?). 



With its coating kept in a plastic, semi-liquid condition with 

 heat from the unit (p), the fabric (a) receives from tongs (.h) 

 set singly or in series across its surface a great number of up- 

 standing hairs in spaced relation. The latter, stuck endwise into 

 the binder, are pressed by a roller (i) into the binder so that 

 the hairs will incline in one direction, and they are in turn 

 combed with a rotary brush (/) to remove tangles and to give 

 them a fur-like finish. The hair-coated strip is then carried over 

 the vulcanizing unit (k) and the plastic rubber composition on 

 the ends of the hair is vulcanized, firmly fastening the filaments 

 to the base, after which the finished strip is coiled on a roll (d). 

 If desired, the fur may be cooled with air blasts from perforated 

 pipes (m) and (»). 



As stated, the primary purpose of the inventor is to produce 

 in a cheap and continuous manner a material suitable for use 

 as a substitute for fur and which may be cut up into a great 

 variety of sizes, but it is conceivable that with the further im- 

 provement of the apparatus and the process the products may 

 closely appro.ximate in utility, appearance, etc., some of the 

 most valuable pelts. He would employ either natural hairs, such 

 as may be a by-product in the making of leather from natural 



