236 



THE INDIA RUBBER WORLD 



Janlary 1, 1921 



RrBBER Resin. Sec Deresinated ruMn-r. 



South American Rubber. Crude rubber produced in South 

 America. The name was lirst applied to Fara rubber, but later 

 extended to embrace caucho, Ceara and maiigal)eira sorts. 



Synthetic Rubber. An artificial rubber or rubber-like substance 

 produced from isoprene, homologous hydrocarbons, or the like. 



Washed Rubber. Grades of crude rubber wholly or partially 

 cleansed by washing with water. 



West Indian Rubber. Sec Central .\merican Rubber. 



West Indian Rubber. CasHlloa rubber from Central or South 

 America, shipped from ports in the West Indies. 



Wild Rubber. A commercial term descriptive of rubber col- 

 lected from uncultivated plants by native methods. The product 

 is received in a variety of shapes, is not uniform and often contains 

 bark, sand and adulterants. 



The forms in which wild rubl)er comes to market are: 



Baixs. Irregular, round or oval shaped masses of rubber, run- 

 ning "from half an inch in diameter to two feet or more. Small 

 flattened balls are also called buttons. Balls from half an inch 

 to two inches in diameter are often designated as marbles. Large 

 balls, as smoked-cured Para are known as pelles, biscuits, hams. 

 Large balls of air-cured rubber, as coarse Para, are called heads, 

 or negro heads. 



Biscuits. Another name for pelles, also applied to oblong cakes 

 cut from lumps. 



Bottles. Fine or medium Para made up in bottle-shaped pelles. 

 Xot practiced at present. 



Buttons. Balls of a small size, slightly flattened. 



Cakes. Irregularly, round, flat disks. 



Clusters. Small balls adhering in masses of varying size and 

 shape. 



Flakes. Thin irregular sheets. 



Heads. Large balls made by compressing masses of rubber 

 together, forming an adhesive mass. (Negro heads.) 



Lumps. Large pieces, varying in size and of irregular shapes, 

 weighing from 20 to 100 pounds. Before shipment, lumps are 

 often cut up into buttons and strips. 



Marbles. Similar to balls, but of a diminutive size. 



Niggers. Balls which have been kneaded into different sized 

 masses so that the original shape has disappeared. 



Nuts. -Another name for thimbles. 



Oysters. Irregular, thin sheets hanging together like the two 

 halves of an oyster. 



Paste. Masses of soft, semi-fluid rubber. 



Sausage. Rubber which has been rolled or wound into finger 

 or sausage shapes. 



Scraps. Small pieces of rubber of a variety of shapes, usually 

 lumped together into large balls. 



Sheets. Thin, flat, rectangular plates. 



Slabs. Very thick, rectangular sheets. 



Spindles. Threads of rubber which have been wound about a 

 stick which is later removed by cutting open the mass. 



Strips. Long, narrow thongs of rubber of varying length and 

 thickness. 



Thimbles. Cubes about an inch for each dimension. 



Tongues. Small, oval sheets. 



Twists. Threads of rul)1)er wound into l)alls. 

 To be CO II till tied 



The Manufacture of Balata Belting 



Balata belting was first manufactured by R. & J. Dick, of 

 Glasgow, Scotland, about 1884 and patented by them in the 

 following year. Since that time it has been demonstrated 

 to be of special value under certain exacting conditions of service 

 in power transmission. 



The foundation of balata belting is heavy cotton duck impreg- 

 nated with balata gum and plied together. The processes of 

 working balata have some resemblance to those used in rubber 



PREPARATION OF BELTING DUCK 



The duck employed in balata belting may he of the weights 

 used in ordinary rubber belting, namely, from 28 to 32 ounces 

 per square yard. Before treatment with balata composition, 

 however, it is necessary that all oily matters and sizing contained 

 in it be wholly removed. For this purpose it is placed in a 

 dyer's vat with a solution of soda crystals and boiled a couple of 

 liours by the injection of steam. To facilitate the extraction of 



M^^^^ 



Fig. 1. Slioine Machine 



Fig. 3. Washing Uill 



Fig. 2. tJincing Machine 



Fig. 4. Slieoting liachine 



Fig. 5, Lirying titove 



David Bridge t^ Co.. I inutrd 



manufacture, the chief difference perhaps being the omission of 

 vulcanization, for balata is not vulcanizable but, like gutta percha, 

 is plastic at the temperature of boiling water and at ordinary tem- 

 peratures is firm and possessed of great tensile strength but not 

 much elasticity. These characteristics necessitate special de- 

 partures in the methods of working balata. 



foreign matter the- duck is reeled through the batli by a hand- 

 operated reel mounted on the vat. 



On this reel it is allowed to drip previous to subscQuent dry- 

 ing in a dry loft and final drying on a triple-cylinder power 

 dryer, from which it is delivered bone dry, ready for impregna- 

 tion with balata. 



