GERMAN FENCING WIRE

Dominion, Volume 11, Issue 187, 27 April 1918, Page 10

GERMAN FENCING WIRE

HOW IT HAS DETERIORATED AN EXPERT'S DEDUCTIONS Writing on the subject of fencing wire, now a very high-priced article in New Zealand, Mr. .1. Orchiston, Chief Telesl'?A> r Engineer of the Dominion, says:Much loss to the farming interests throughout the Dominion has resulted during recent years from the use of cheap German and other low-grade fencing wires, which only had a lifo of half a dozen yea.rs or so. The loss can bo safely placed at hundreds of thousands of pounds. ' Somo time ago there was a considerable amount of investigation in the United States as to the cause of the rapid deterioration of modern wire as compared to that produced formerly. The conclusion arrived at was that the j chief reason for the deterioration was duo to the admixture of manganese in the process .of manufacturing the steel. "Each molecule of manganese left in the metal will set up local galvanic action, with the result that the wive will become pockmarked or flayed off in junks as if some sharp instrument had been used to bite pieces out of the metal. Other impurities in the metal will, of course, all tend to its disintegration. Tho purer the metal the less oxidisation; in other , words, tho longer it will last. "Prior to some forty years ago all wire was made' of ordinary "iron, but on the advent of what might'bo termed tho steel era the manufacture of iron wiry practically ceased. The cheaper steel wire also gained favour from the. fact that it would stand a greater strain beforo stretching. After some years it was discovered that it was not so lasting as Ihe previous iron wire. It then became the practice to largely galvaniso fencing wire, but even this did not make up for the impurities resulting from the cheaper methods' of manufacture. The Germans seem to have led the way in regard to cheapness and poor quality, and British firms had to follow 6uit or simp'Ty lose the trade, as the average farmer had and has no meane of telling one vviTO from another. The cheap German wire looks | just as well, or in fact sometimes better from outward appearance, as that of the superior British article. I leave it to the farmers themselves to judge how many have knowingly bought German wire because it was ten shillings a ton cheaper and have been sorry, for themselves afterwards. -i

| "The Post and TelegTaph Department is, of course, tho largest user of wire in tlio Dominion, and I think a little outline of its experience might be of in- ; lerest. In 1864 the General Government : commenced the erection of telegraph lines from Marlborough to Southland. A considerable quantity of the wire then erected is still in use, and what has been dismantled was principally on account of alterations to the route, etc. A great deal of Ihe wire erected in both islands during tho 'sixties is still doing good work, and likely to last many years longer if left alone. After 1882 1 observed a marked difference in tho class of wire coming to hand, and subsequently learnt that it was steel, ami that as the British. Post Office had agreed to take steel wire at a. cheaper rate than the previous iron wire tho manufacturers had practically ceased to make iron telegraph wire by tho old process. Tho result is that tho wire erected during tho later 'eighties and 'nineties is not so good as that of the 'sixties and 'seventies, arid most of it will have to Ire replaced before that erected during the earlier period. "At odd times between the years of 1895 and 1910, when the supply of standard wire had run out some fencing-wire was purchased to pressing works. In one easo such wiro erected in 1905 began to fall down in 1911, and had to be wholly renewed in 1912, a total life of only seven years, whereas much of the fifty-thrce-year-old wire,_ as already indicated, is still serviceable in the South Island. Naturally, one is apt to ask, Can nothing be. done to Tcmedy or check the use of such inferior material? Thcro is a very simple means of arriving at tho approximate purity of the iron. Tho purer any metal is the greater its electrical conductivity; consequently tho more impurities the poorer the conductor. Beckoning tho conductivity of absolutely pure iron at, 100 per cent., tho best class of telegraph wire is expected to represent 97 per cent, from an electrical conductivity point of view. It is doubtful, however, if any steel wire can bo obtained as high as this, and tho British Post Office Telegraphs has set the minimum standard as low as 87 per cent., which has been the minimum adopted in New Zealand. I am, however, of opinion that this is too low, adid it is proposed to raise the standard. The old telegraph wire erected in tho 'sixties approximated 95 per cent. "Some recent importations of a new class, of iron wire manufactured in America have reached tho 97 per cent, mark, and it'is anticipated that this wire will be good for at least fifty years, although the galvanising does not comply witli our specifications. Some fencing wire tested by mo has been as low as 50 per cent., which is a clear indication that such wire will have a short life. During the last seven years hundreds of tons of telegraph wire have boon rejected in AVellinglon, much to tho disgust of the manufacturer!) and their local representatives. ' Although the purity of tho metal, is oFpniinary importance from a lasting point of. view, it is also desirable that the wire should be well galvanised, and I may here state I have never found any fencing wire which would comply with our specifications in this respect. In so far as the tensile strength of tins low-grade wire is concerned little fault can be found with it when new. In fact, it. will invariably bear a greater strain before stretching than tho first-class wire. j», "With a. view to a«sistiiur those in need of good wire, the Hon. tho PostmasterGeneral has been pleased to approve of the Department undertaking the testing of fencing wiro for. the percentage of conductivity, and also for galvanising, at tho small charge of two shillings and sixpence per sample. Each sample should consist of eleven feet, to be made up in a coil of not less than, sny, nine inches in diameter, free from kinks."