METAL SPRAYING.

Hauraki Plains Gazette, Volume XXXV, Issue 4771, 3 November 1924, Page 3

METAL SPRAYING.

A WONDERFUL PROCESS. RUSTLESS IRON COAT FOR WOOD. Great interest was attracted by a detailed description of the methods and advances made in metal spraying by Mr T. H. Turner and Mr W. E. Ballard at the Institute ofi Metals (states the “Morning Post”). Although this process has been known ’for the past ten years, its development was retarded by the war, and it is now only just opening out, and the full possibilities have not yet been realised. Briefly, it consists of treating metals of practically every description as if they were scent in a scent spray, and depositing them .on any desired object in the form of a fine .adherent dust. The metal surface thus obtained can be burnished or polished to any degree, and is permanent. The spray is produced and projected by an instrument resembling a large automatic pistol,.but the magazine is loaded with a reel! of wire in place of cartridges, and the propulsive charge is composed ot oxygen, hydrogen, and compressed air. As the wire reaches the muzzle it is converted into a cloud of tiny metallic particles, which, travelling at .a very hivh speed, become molten on striking the target, and form a. solid coating. In spite of the great heat of the oxv-hydrogen flames used in vaporising the metal, the most delicate, as well as the most robust, materials are undamaged by the process, and of this many interesting examples were shewn. DESIGNS ON SILK. Designs produced by spraying silk ■ and cotton fabrics with brass and , copper alloys were shown, the method being to place a paper stencil over the material and direct the pistol at it. Fabrics are not affected by washing.- Even thin paper is not scorched, and the palm of the hand can be plated with pure metal without discomfort, and glass can also be coated in the same manner; The industrial - applications are and are now being used in six . European countries as well as America. A coating of any thickness of non-corrosive metal can be applied to any structure, thus preserving it from the action .of weather or chemical fumes —a matter of great importance in shipbuilding and engineering in general. It is possible to spray a nonporous coat of tin, lead, or zinc on any object, and also to preserve wood by spraying it with rustless iron. EXPERIMENT WITH. PLATINUM. A feature of the process that will be watched with interest by chemists is the experiment of coating porcelain and silica* with platinum. The high cost of this rare metal has hampered many research workers in chemistry, for it is absolutely essential for certain operations, and the present cost of even a tiny platinum crucible is beyond the means of the average private experimenter. Should Die result prove Satisfactory, and Mr Turner told a representative of the “Morning Post” that there was every Bhope that it would, the scope of research of the smallest research worker will be greatly increased. Solid bars that can be filed and machined can also be produced by the process. Many samples were shown, including bells made from copper and zinc,' giving a characteristic ring which has hitherto been regarded as impossible in the case of metal ob- • jects built up in this way.