[57] Ibid., January, 1920, p. 68.

Other less usual methods of preparation, referred to in the earlier part of this book, do not call for particular mention, as the properties of the rubber do not differ much from ordinary sheet or crepe. It is mainly a matter of variation in rate of cure.

This short account of the vulcanising properties of plantation rubber would not be complete without a reference to Fine Hard Para, the premier rubber of the Amazon. This rubber has come to be regarded as the standard high-grade product with which plantation rubber may be compared, and many manufacturers are still of the opinion that it is unsurpassed by any plantation product. Yet, when subjected to the ordinary vulcanising tests, we find that samples of Fine Hard Para give figures very similar to average plantation rubber; indeed, it is not difficult to find specimens of plantation rubber which give appreciably higher figures on testing. It is claimed, however, that Fine Para is more uniform than plantation rubber, and can be relied on always to give the same results. Yet tests on a series of Fine Hard Para specimens gave variations in rate of cure similar to those found for plantation. Some figures were published, which tended to show that the variation was smaller for Fine Para, but it turned out that each of the samples taken for examination consisted actually of a number of slices cut from different balls, so that greater uniformity was not unexpected.[58] The superiority of Fine Para is, therefore, somewhat of a mystery. It is probable that some manufacturers prefer to use it because they feel safer with it, and know actually how it will behave from long experience. In one respect Fine Para is possibly superior to most plantation rubber—that is, for the preparation of raw rubber solution for sticking the seams of waterproof garments, and for similar purposes. The method of preparation may well influence the strength of the raw rubber when used for this purpose. Plantation rubber has been prepared in the same manner as Brazilian Para, in particular on an estate in Java. The product resembles Brazilian Para in appearance. Vulcanising tests gave satisfactory figures, but, as already stated, this would not serve to show that the rubber was equal to Brazilian Para from the manufacturer’s standpoint.

[58] Bulletin R.G.A., September, 1920, p. 347.

INDEX

Acetic acid,[74], [279]
Acid, acetic,[74], [279]
—, carbonic, gas,[289]
—, formic,[279]
—, hydrochloric,[282]
—, hydrofluoric,[282]
—, mixing, with latex,[79]
—, nitric,[282]
—, oxalic,[279]
—, pyroligneous,[282]
—, quantity of,[76]
—, sulphuric,[279], [286]
Acids for coagulation, effect of, on rate of cure,[323]
—, quantities necessary for modern requirements,[78]
Air-drying, aids to normal,[143]
—, of crepe, rate of,[138]
—, progress of,[140]
Alcohol, coagulation with,[289]
Alum, coagulation with,[282]
Anti-coagulant for transport,[61]
Anti-coagulants,[46]
Artificial driers,[133], [148]
Ash on sheet,[276]
Assembling cases for shipment,[156]
Bags for packing,[154]
Bakau,[147]
Bales for packing,[154]
Bark in crepe,[232]
— — shavings,[56], [123]
— — sheet,[276]
Bases in vulcanised rubber,[322]
Basket plants,[10]
Blanket crepe, properties of,[324]
Blemishes of surface,[252]
Blister in sheet,[272]
Block rubber,[129], [246]
Breaking down of rubber,[304]
— load of test piece,[311]
Bubbles in sheet,[269]
Buildings,[159]
Bulking latex,[69]
Byrne curing process,[270]
Calendered sheet,[304]
Carbon dioxide,[289]
Carbonic acid gas,[289]
Cases, choice of, for packing,[153]
Catalysts, natural, in rubber,[312]
—, vulcanising,[312]
Centralisation of factories,[221]
Chinese vinegar,[286]
Chinosol,[238]
“Chula” drier,[148]
Clippings, sheet,[275]
Coagulant,[111]
—, choice of,[74], [278]
—, quantity of,[113]
Coagulation,[74], [111]
— centres,[62]
—, premature,[46]
—, spontaneous,[294]
— with alcohol,[289]
— — sugars,[287]
— — various salts,[288]
Coagulum, soft,[249]
—, spongy undersurface of,[249]
—, tearing of,[249]
—, transport of,[59], [63]
—, working of,[103]
Coefficient of vulcanisation,[319]
Collecting latex,[38]
— pails,[48]
Collection, advantages of early,[60]
Combustion, rate of, in smoke house,[191]
Compound crepes,[126]
— — No. 1,[151]
— — No. 2,[151]
Contents of cases, weight of,[156]
Copper salts, cause of tackiness,[243]
Cotton fibre in crepe,[230]
Creosotic substances,[146]
Crepe, air-drying of,[132]
—, bark in,[232]
—, bearing of defects in, on manufacture,[316]
—, bisulphite streaks in,[235]
—, colour of fine,[114]
—, dirt in,[227]
—, dirty edges of,[225]
—, drying houses for,[178]
—, fibre in,[230]
—, general style of finish,[223]
—, grades of,[150]
—, greenish, tacky streaks in,[228]
—, iron stains on,[225]
Crepe, No. 1 fine pale,[110]
—, oil marks on,[226]
—, oxidation streaks in,[234]
—, rate of air-drying of,[138]
—, rust stains on,[226]
—, smoked,[130]
—, surface moulds on,[241]
—, weight increased in drying house,[141]
—, yellow latex streaks in,[234]
— rubber, defects in,[223]
— —, lower grades of,[120]
— —, preparation of,[110]
— —, tensile strength of,[313]
Cups, cleaning,[40]
—, water in,[44]
Cure, rate of,[318]
Curing,[307]
Da Costa process,[290]
Decentralisation of factories,[221]
Defects of sheet, infrequent,[276]
Derry process,[293]
Designs and “layout” of tanks,[176]
Dirt in sheet,[276]
Discoloration of rubber, dark,[249]
Drains for tanks,[176]
Drier, Colombo Commercial Company’s,[136]
Driers, artificial—for crepe rubber,[133]
— —, for sheet rubber,[148]
—, “Chula,”[148]
—, vacuum,[134]
Drum furnaces, horizontal,[189]
Drying chamber, floor of,[187]
— —, arrangements of,[186]
— houses for crepe,[178]
— —, hot air,[182]
— —, ventilation of,[185]
— —, windows of,[185]
— of rubber,[132]
—, period of,[145]
—, rate of, effect on rate of cure,[323]
Earth scrap,[124]
— —, collection of,[58]
Edges, thickened, after rolling,[251]
Elongation of test piece,[311]
Ends, thickened, after rolling,[251]
Engines,[170]
—, position of,[174]
Factories,[172]
—, centralisation of,[221]
—, decentralisation of,[221]
—, number of floors,[174], [178]
—, ventilation of,[180]
—, windows of,[181]
Factory buildings, situation of,[216]
—, choosing site for,[220]
—, ideal arrangement of,[162]
— operation,[65]
Fibre cotton, in crepe,[230]
Field maintenance,[13]
Fine hard Para properties of,[325]
First latex and other grades, percentage of,[59]
Floor of drying chamber,[187]
— factories,[173]
— furnace room,[196]
Formalin,[87]
Formic acid,[74], [279]
Formula for test mix,[311]
Freezing (coagulation) process,[293]
Fuel, consumption of,[196]
Fuels for smoking,[146]
Furnace room, floor of,[196]
— —, Petaling type of,[192]
Furnaces, horizontal drum,[189]
—, “pot,”[188]
Germination,[6]
Grades, number of,[151]
Grading,[150]
Grafting,[8]
Grass squares,[14]
Greasiness before smoking,[252]
— of surface,[258]
Grit in crepe,[232]
Hand rolling sheets,[104]
Hevea Brasiliensis,[1]
Hot air drying houses,[182]
Hydrochloric acid,[282]
Hydrofluoric acid,[282]
Ilcken-Down process,[298]
Instruments, method of using,[100]
—, recording,[144]
—, standardising,[98]
Lallang, eradication of,[15]
Latex, bulking,[69]
— cups, choice of,[40]
—, decomposition of, in the field,[270]
—, first and other grades, percentage of,[59]
—, first quality,[150]
—, mixing acid with,[79]
—, mixing sodium bisulphite solution with,[117]
—, preliminary treatment of,[65]
—, reception of, at the store,[65]
—, standard,[96]
—, standardisation of,[69], [110]
—, straining,[67]
—, transport of,[59]
Light, importance of, in factories,[172]
Litharge,[312]
Load stretch curve,[312], [319], [320], [321]
Low grade rubbers, fibrous matter in,[124]
Lower grade rubber, care in manufacture,[129]
Lubrication of machines,[166]
Lump rubber, naturally coagulated,[120]
Machinery,[159]
Machines, access to,[169]
—, adequacy of,[160]
—, arrangement of,[168]
—, lubrication of,[166]
—, position of,[173]
—, sheeting,[166]
—, speed of,[162]
Mangrove,[147]
Marking sheets,[105]
Metrolac,[98], [100]
Michie-Golledge system,[138]
Mildew on surface,[260]
Milky residue on serum,[249]
Mixing acid with latex,[79]
Moist glaze of surface,[258]
Mould on surface,[260]
Moulds, surface, on crepe,[241]
Natural catalysts,[312]
Nitric acid,[282]
Nurseries,[9]
Overcured,[307]
Overvulcanised,[306]
Oxalic acid,[279]
Oxidation, prevention of,[56]
—, variation due to,[254]
Packing,[150]
—, bags for,[154]
—, bales for,[154]
—, cases, choice of,[153]
—, folding for,[155]
—, methods of,[156]
—, rooms,[211]
Pale crepe, No. 1 fine,[110]
—, rubber, former methods of making,[118]
—, sheet,[89]
Patches,[259], [260]
—, virgin,[259]
Payment by result,[53]
Perished rubber,[306]
Physical properties of rubber, variation of,[317]
Pits for smoke houses,[188]
Pitting of surface,[250]
Plantation rubber, testing of,[309]
Planting,[1]
Plasticising of rubber,[304]
Plasticity of plantation rubber,[309]
“Pot” furnaces,[188]
Power units,[170]
Premature coagulation,[46]
Preparation, special methods of,[290]
Pyroligneous acid,[282]
Racks,[186]
Rate of cure,[307]
Raw rubber, physical properties of,[313]
— —, tests on,[309]
— —, uses of,[315]
Recommendations, Rubber Growers’ Association,[152]
Recording instruments,[144]
Ribbing of sheet,[274]
Rolling,[251]
Rolls, grooving of,[164]
— running hot,[165]
— — “free,”[165]
Roof of smoke house,[197]
Rubber, drying of,[132]
Rubber Growers’ Association, Recommendations,[152]
Rubber, properties of,[313]
—, smoking,[109]
Rust, cause of,[267]
— on sheet,[262]
—, treatment to prevent,[265]
Scrap washers,[57], [124]
Screw plug, unsatisfactory,[73]
Seed at stake,[10]
Seeds,[2]
Selection,[5]
Senang folder,[156]
Serum, milky residue on,[249]
Sheet, ash on,[276]
—, bark in,[276]
—, bearing of defects on, in manufacture,[316]
—, blisters in,[272]
—, bubbles in,[269]
—, clippings,[130], [275]
—, creases in,[251]
—, dirt in,[276]
—, “dog ears,”[251]
—, grades of,[151]
—, infrequent defects of,[276]
—, pale,[89]
—, ribbing of,[274]
— rubber, artificial driers for,[148]
— —, defects in,[249]
— —, preparation of,[89]
Sheet rubber, rolling and marking of,[102]
— —, tensile strength of,[313]
—, rust on,[262]
—, splinters in,[276]
—, stickiness in,[274]
—, style of,[101]
—, support marks on,[273]
—, surface pattern of,[274]
—, thick ends of,[275]
Sheeting machines,[166]
Sheets, mis-shapen,[251]
—, thickened patches in,[251]
—, torn,[251]
—, unevenness of appearance,[253]
Short weights,[157]
Skimming,[100]
Skimmings,[122]
Slab rubber,[299]
— —, properties of,[324]
Slope,[312]
Smoke curing of sheet rubber,[143]
— —, temperature of,[144]
—, houses,[183]
— —, Barker patent,[209]
— —, Devon type,[200]
— —, iron stoves for,[189]
— —, Jackson type,[200]
— — of brick,[198]
— — rate of combustion in,[192]
— —, roof of,[197]
— —, “Third Mile” type,[199]
— —, types of,[198]
Smoked crepe,[130]
— sheets, colour of,[255]
— water for coagulation,[286]
Smoking, effect on rate of cure,[323]
—, greasiness before,[252]
— rubber,[109]
Smooth rolling of sheets,[104]
Sodium bisulphite,[80], [114]
— —, abuse of,[85]
— —, care of,[116]
— —, deterioration of,[115]
— —, evaluation of,[115]
— —, making a solution of,[85]
— —, quantity of,[84]
— —, residual traces of,[86]
— — solution, mixing, with latex,[117]
— sulphite,[86]
— —, deterioration of,[115]
— —, evaluation of,[115]
Sorting,[150], [152]
— rooms,[211]
Spewing,[305]
Splinters in sheet,[276]
Spontaneous coagulation,[294]
Spot disease,[235]
— — in sheet rubber,[273]
Spots,[259], [262]
—, virgin,[259]
Standard latex,[96]
— sheet,[102]
Standardising instruments,[98]
Stickiness in sheet,[274]
Stock solution, method of making,[75]
Storage of rubber,[212], [216]
Stoves, iron, for smoke houses,[189]
Straining latex,[67]
Streaks,[262]
Stumps,[9]
Sugars, coagulation with,[287]
Sulphuric acid,[280], [286]
— —, buying,[280]
— —, formula for use of,[280]
— —, storing,[280]
Sun-drying sheet rubber,[147]
Support marks on sheet,[273]
Surface blotches, coloured,[249]
—, dull or black,[258]
— pattern of sheet,[274]
Tackiness, cause of,[243]
—, copper salts cause of,[243]
— in rubber,[242]
Tanks,[90]
—, care of,[94]
—, designs and “layout,”[176]
—, drains for,[176]
—, installation of,[93]
—, situation of,[175]
—, water-supply for,[177]
Tapping,[38]
—, former systems of,[29]
— knives,[38]
— systems,[38]
Tartaric acid,[279]
Tensile product,[314]
Test mix, formula for,[311]
— pieces, making of,[310]
Testing of plantation rubber,[307]
Thick ends of sheet,[275]
Thinning,[19]
Timber for smoking,[147]
Tool sheds,[216]
Transport,[60]
— by coolie,[62]
— of coagulum,[59], [63]
— of latex,[59]
Trays,[167]
Treatment of rubber in the factory,[301]
— to prevent rust,[265]
Tree scrap,[55], [122]
— —, care of,[56]
— —, oxidation of,[56]
Trees per acre,[26]
Trenches, silt catchment,[11]
Uniformity,[90]
— in colour, lack of,[246]
Vacuum driers,[134]
Variation due to oxidation,[254]
Vegetable extracts,[289]
Ventilation of drying houses,[185]
— factories,[180]
Verandas,[175]
Virgin spots,[258]
Viscosity of rubber solution,[309]
Vulcanisation,[301]
—, rate of,[318]
Vulcanised rubber,[318]
— —, tests on,[309]
Vulcanising,[307]
— catalysts,[312]
—, “heat,”[306]
Washers, scrap,[57], [124]
Washings,[122]
Water-supply for tanks,[177]
Weeding, clean,[13]
Weights, “short,”[157]
Wickham process,[293]
Windows of drying houses,[185]
— factories,[181]
Working of rubber,[304]
Yields,[23], [25]

Transcriber's notes: