Metal Spraying in the Radio Industry

Abstract

IT is today the normal practice to protect all ferrous metal parts used in the manufacture of chassis, decks, cabinets, etc., for commercial radio work, with an applied spraying of non‐ferrous metal. The metals most commonly used are zinc and aluminium, although it is right to say that practically any metal, which can be drawn into a wire, can be sprayed for protection purposes. Zinc is perhaps the most generally used, on account of its relatively low cost. The sprayed metal reacts favourably to cleaning with wire brushes and an attractive matt finish is readily obtained without the trouble attendant on normal polishing. Hand or rotary brushes can be used with flexible shafts for small articles or large areas. The applied coating can be of various thicknesses, dependent upon the type of atmospheric conditions it is expected to encounter, such as industrial pollution, salt‐laden sea air and spray, and tropical or highly humid atmospheres. The thickness is measured by a direct‐reading contact meter and 0.003 to 0.010 in. depth of metal applied is quite adequate protection for 12 to 15 years.