GB497525A - Methods for imparting different colourations to respective areas of a metallic surface - Google Patents

Abstract

497,525. Ornamenting metals. MARX, L., and DAMIEN, M. March 22, 1938, No. 8842. Convention date, March 22, 1937. Drawings to Specification. [Class 93] Designs are produced on metals, such as aluminium or alloys thereof, or copper, by protecting parts of the surface by means of masks, stencils, or coatings, sandblasting the exposed parts, producing an oxide coating on the whole or parts of the surface, and then colouring the coating, the colours formed on the sandblasted portions contrasting with those on the remaining parts. Before colouring, parts of the surface may be protected by masks &c. ; or, after colouring, parts of the coloured surface may be protected, the colour removed from the remaining parts, e.g. by forming an oxide-layer thereon, and those parts recoloured. Also, sandblasting may be applied before or after any one of the colouring &c. operations. The oxide coating may be formed by electrolysis using acids or alkalies, and colouring may be effected by applying a basic organic dye fixed by a mordant, or by double decomposition on the oxide layer of a coloured insoluble inorganic compound, e.g. by treatment with a solution of lead acetate and potassium bichromate. Also, a coloured metallic oxide may be precipitated in the aluminium layer by treatment with a metallic compound and a solution of an oxidizing-agent. The sandblasting may be combined with other methods of surface treatment such as cutting, stamping, hammering, dyeing, embossing, turning, or moulding. Specifications 387,806, 391,903, 401,270, 477,286, and 483,776 are referred to.