HOW SOLES ARE TESTED

Hokitika Guardian, 7 December 1929, Page 7

HOW SOLES ARE TESTED

SECRETS OF LEATHER RESEARCH

THE WATTLE PROBLEM

(By E.A.A. in The Dominion)

Not many people realise what a lot of trouble ,s taken to give them decent long-wearing, water-resisting soles. Some, in fact, put faith in syntactic .substitutes, and despite the fa t every third person met in the si root stands upon New Zealand leather, scarcely a single pers ;n knows tiie place where their soles arc tested.

It seems there is nothing hit or miss about this sole-testing business. ►Soulless mechanical -devices, boiling chemicals and electrical testing machines make it weli-nign impossihe for a bit of inferior leather to masquerade in bo'rowed plumes.

The man who tests our soles asked me to sit down. J did so, beside a ehemi.nl balance, a few odd hits of tanning materials, and some lengths of leather. “it’s only a year,” he apologised, “since this leather research got into its stride. The Government pays half and the tanneries half. I can say definitely that New Zealand leathers are quite as good a® any others in the world. What struck me most when I first arrived from London was the need for uniformity in output, the quality appeared varied—besides, there was a lack of finish about tbe products. This, of course, affected tli-eir selling value, but fundamentally, from numerous tests 1 have made, imported leathers are now no better than tbe local product. T go round obtaining samples of leather from tanneries in New Zealand and compare them with imported leathers. We analyse them all.” » FIXING THE STANDARD. He led me to a cupboard, which lie opened, thereby liberating a gas attack. A bit of best ox leather for a sole was being boiled in sulphuric acid. Jt was an unpleasant operation. 1 choked. “By boiling it like that it is possible to discover just what proportion of r-lie hide is being turned into leather,’.’ he explained. I was glad I had never thought of doing such a thing with one of my old boots for, as a family fireside experiment, it would never have become popular. For one thing, you couldn’t breathe beside tbe fiery concoction. England, it seems, after years of practice, has found that if 80 per cent of the bide is turned into leather it is the best proportion. New Zealand leathers on a list I was shown were only a decimal point below this figure. Australia, in this particular case, stopped short at 76 per cent. “Thanks to these research facilities local leather,” 1 was told, “can now be produced up to these standards and kept there. If a manufacturer starts to fall off he is informed. 1 ” “Don’t they mind?” I asked. He laughed and handed me a letter. It was in reply to one stating that the standard had become low. Far from minding, “we want,” said this manufacturer, “to reach top standard and it is essential for us to know just how we stand.” ESTiMATING DURABILITY. Devices to discover just how we stand in our local leathers filled the room. A mechanical counterpart of the famous seven leagues boot was buzzing away wearing out ten or twelve sole samples in a matter of hours. The samples some four inches long, were screwed to the circumference of a wheel about ' two feet across. This wheel, in revolving, rested on another wheel of emery at right angles to it and beneath it. An electric motor turned tlie seven league boots and the leathers, in turning tbe emery wheel wore themselves out After revolving 15,0 X) times, the difference in weight of the samples before and after test indicated their wearing propensities. “The best way of all,” I was told, “is to actually wear different samples on either foot. But it’s very slow.” The wear-testing machine takes one prospective sole the equivalent of a 200mile stroll on coarse emery in a few hours, instead of months. New Zealand leathers now nut up as good a showing under this drastic treatment as any imported leather, including the best British. Ekewherc samples of our soles were undergoing tests, for grease content. '1 bey are subjected to a prolonged dry clean with ether. This washes out all the grease, which can then be measured. Too much grease makes shoe leather soft and quick-wearing; t o little makes it brittle and unworkable. WATTLE FOR TANNIN. On the floor here and there were little- bundles of what looked to be faggots. “Wattle hark,” the tester of soles remarked, “for tannin tests.” Not only is leather tested here, but various tannin products from all over the world are tried out. Amid a forest or tubes and burners some local wattle tannin from Auckland was being' tested. .1 was told New Zealand wattle produces excellent tannin. Oak knk, famous in school hooks of some quarter ol a century ago, is not used 10-day on account of expense. Wattle has taken its place and the southern hemisphere now tans the leathers of the northern hemisphere. Large quanlites of wattle hark comes from South Aliica, where 1 , with cheap labc’ir, it can compete in the markets , I the J world.

“Wattle grows abundantly in New Zealand,” I was informed. “Well, why don’t we use local wattle?’’ 1 asked. Wattle , 1 ike all plants, so soon as a use was found for it, went and got some stupid disease. In this particular case our local wattle suffers from a fungus disease that affects the trees and makes tlie stripping of its hark very difficult. Until the agricultural or the plant pest pe.ple can line! a cure it seems we shall be deprived of home-grown tannin. \v attic bark costs about £l4 a ton, and, if a cure can lie found, a new industry might be expected to spring up. The trees reach a suitable age for tannin purposes after about nine years. From an acre of land four or live tons of bark can be harvested. These trees grow in soil useless for other purposes and,- therefore, do not interfere with agriculture. Possibly the pumice lands might be found suitable for wattlegrowing. HOW AYE STAND. Our leather problem roughly stands at present like this: AVe’vc got the hides and calk skins, about a miljjon or so a year; we’ve got tbe tanneries; but wretched fungus lias cornered tlie wattle trees. The sole-tester looked at my -shoes. “Well?” J asked. “You are wearing synthetic stuff for your soles,” he said, 7n a voice that' might be used by a jeweller reprimanding a duchess for wearing imitation pearls. “Well ?” I asked. “Good shoe leather” lie explained, “contains 10 per cent, of air. It allows your feet to breathe and acts as an insulator at the same time.” I am still pondering over this problem. At any rate, people with synthetic soles can look an ox straight in tlie face without the slightest proprietary twinge.