At The Wheel

NZ Truth, Issue 1211, 14 February 1929, Page 19

At The Wheel

ROMANCEOF RUBBER Many Interesting Processes From , Tree To Tyre

Does the motorist, skimming; m comfort over rough country roads, ever realise the enormous contribution that rubber has made to the motor industry? Does he realise it was the development of the pneumatic tyre that made it possible for mechanically propelled vehicles to travel fast over bad roads?

RUBBER is. used to a great extent m the manufacture of tyres, and a very large number of Australians •are now employed m this industry. In addition to tyres, rubber is utilised for many other motor accessories: shock absorbers, door stops, matting-, insulating taps, windscreen strip, window fittings, etc., etc. The mechanical department of a 'large rubber company is of '■ considerable interest to the motorist. Granted that rubber is of predominant importance m the motor industry, it is interesting to go back to . its discovery and the gradual realisation of its value. Early m the sixteenth century, Spanish pioneers m Mexico found the natives playing a game with a hard black ball of remarkable resiliency, which they had made from the resin of a tree known as "Ulaquhuil." The Spaniards learnt from the natives how to waterproof their cloaks and to make waterproof boots and pouches of this substance. Samples were sent to "Europe, but little or no importance was at that time attached to the discovery. It was not until much later, with the discovery of vulcanisation, that, rubber became a product of such far-reaching importance. Vulcanisation is a process which makes rubber almost entirely unaffected by changes m atmospheric temperature; and also adds greatly to its strength and elasticity. • Then came the question of an adequate supply of raw rubber. Up to the latter part of the nineteenth century, most of the rubber supply came from Central and South America. A great deal of it was of inferior quality,

the best rubber — Para rubber — coining from tho Amazon Valley. .Through the efforts of Sir Arthur Wickham, -who devoted a lifetime to the study of this subject, it was found that the Eastern tropics would prove particularly suitable for the cultivation of the trees, and the Indian Government was induced to finance the scheme; and, after great difficulty, Sir Arthur succeeded m conveying a quantity of the seeds to England. Plants were eventually sen); to India, Ceylon, Singapore, the Malay Peninsula and other parts of the East. From that time onw&rds production flourished, and rubber-grow-ing became a profitable and incalculably valuable industry. The trees reach the age of five to six years before they are ready for tapping, that is, opening the cells which harbor the sap and thus obtaining the milk, which is first collected m smnll cups," them m pails, which are emptied into' tanks. A small amount of acetic acid is then added to coagulate the fluid; the rubber can then be washed, pressed, and dried. According to the particular article to be manufactured, the rubber has to be mixed with other materials, so as to give it the required elasticity, softness or tough' ness. Take an elastic band and a motor tyre — it is obvious that, although these are both of rubbcV, it is rubber subjected to entirely different treatment. The processes of mixing, calendaring, and vulcanising are naturally complicated; but to any motorist curious about the manufacture of the tyres and gadgets which help his car along, a visit to one of Melbourne's rubber mills would be .of enthralling interest.