"POWELLISING" TIMBER

New Zealand Times, Volume XXXIII, Issue 7364, 16 February 1911, Page 4

"POWELLISING" TIMBER

AN IMPORTANT INDUSTRY.

THE PROCESS IN OPERATION AT RANGITAUA.

An industry of the very first importancc to the Dominion is now to bo found in active operation at one of the small King Country townships, cm the Main Trunk line, where every day limber hitherto regarded as practically useless is being turned into sleepers, fencing posts, and what not, fit to last with the best wood tho forests can produce. Tho transformation, which means so much to a country whoso timber areas are a steadily decreasing quantity, is being effected at Rangita.ua, a small township about three miles on the AVelliugton side of Ohakune. There the Powell Wood-Process Limited has established extensive .works, cajiable of treating a million feet of timber per month, and which, big as they are, are quite unable to cope with the rush of orders.

A tour of inspection of the works was made on Monday by the Prime Minister, Sir Joseph Ward, with whom was a “New Zealand Times” reporter and a number of other visitors. Tho party was conducted through by tho manager. Mr J. R. Gorton, who explained as fully as possible the process by which even the most common and apparently useless timber is endowed with tho power to resist the attacks of dry rot and tho borer. A SIMPLE PROCESS. Tho whole process is simple, natural and inexpensive, and consists essentially in boiling the wood in a saccharine solution, to which are added certain other substances, to suit the special purpose for which the timber is required. Artificial drying completes the process ami tiie wood is then ready for immediate use. Tho results obtained are said to be very much better than from creosottog, in which force is used; indeed, it is claimed that instead of injuring the fibres of the wood as creosoting does, the process actually strengthens them. In “powellising,” the timber is not subjected to any external pressure or vacuum at any stage of the process. The wood, as it is received, is immersed in a cold solution in large opou tanks. ■This solution is gradually raised to boiling point, and is maintained at this temperature for a certain time, depending on tho size and density of the wood. The whole is then cooled and the wood is removed and placed in a drying chamber, the temperature of which is slowly raised. When sufficient desiccation has taken place the chamber is gradually cooled down. Tho time occupied in the whole treatment is in general a few days, though in special cases and for large sized timber it may be extended to three or four weeks. The action which takes place is as follows: As the temperature of tiie solution in which the wood is immersed .is raised, the air in the wood expands and the greater portion escapes in a series of bubbles. A.s a saccharine solution boils at a slightly _ higher temperature than water, the moisture in tho wood is converted into vapour and escapes along with the air. During the boiling tho albuminous matter in the wood is coagulated and rendered inert. In some measure this coagulation accounts for the strength of the wood being increased by the process. While cooling, the solution is rapidly absorbed by the wood and penetrates to every part of it. MANY ADVANTAGES. During the visit on Monday the party witnessed the opening of a tank and the transfer of the 800 sleepers it contained to the drying chamber, where they were to be .steamed, and then dried with hot air. At the present time the company is executing an order for 180,000 sleepers for the Railway Department. It is also treating large quantities of timber intended for use in railway waggons and carriages, about two million feet of powellisod wood having already been supplied for this purpose. The advantages of the process are at once apparent when it is mentioned that tho timber can be treated immediately on betog brought in from the bush and then being put straight into tho carriages, whereas in. the ordinary way the sawn lumber must bo kept in stock for at least a couple of years to season before being worked up. Then, in addition, it is claimed that there is no waste in timber which has been treated, as the process stops all warpage and splitting, as well as rendering it absolutely immune from dry rot and the borer insects. The permanency of the process is held to have been quite established. For instance, good reliable sleepers can be made out of birch, which previously would not have been looked at for this purpose. The manager mentioned, as an illustration, the experiences of the Railway Department in a swamp near Te Kuiti, where it was found that puriri sleepers rotted in a couple of years. As an experiment, powellised white pine sleepers were put to and on being taken up recently after having been to for two years and a half wore found to be perfectly sound. “Yet in the ordinary way,” remarked Air Gorton, “they would not have lasted for a couple of months.” NO LOSS OF TIME.

It has been found that the treatment is more efficacious on green timber, in fact, as the manager put it, “the greener the better.” No tune, therefore, is lost in the stack, the company being able to treat the timber as jt comes in from the sawmills, a few miles away. In addition to the purposes mentioned, powelliser timber is extensively used in many directions. For instance, it is found very suitable for street blocking, even sort and low-quality timber being rendered hard and ' strong enough to stand very heavy traffic. That the treated wood can be used with advantage in cabinetmaking was demonstrated by a visit to the office on the works, where many beautiful samples were inspected. Many varieties of both hard and soft woods have been treated and then submitted for practical test by furniture manufacturers. In all cases the report was that tho working qualities were improved by Ore treatment, that the wood took polish and varnish quite as well as untreated material and that, in genera], 25 per cent, less paint was required to cover treated timber owing to it being rendered practically non-absorbent by tho molasses filling. The establishment at Rangitaua is the only place in New Zealand where the Powell process is now used, but works are being erected by the Government at Kew for the treatment of timber in the sonth-