Mirror Finish for Many Materials
Page 45
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rACUUM metallizing of metal, plastics, glass and other substances with a highly reflective surface is being ended. The reflective capacity of parts treated in this y is claimed to be rated at 90 per cent, as compared with per cent, for chromium plating.
Me process consists of applying a preliminary lacquer e to the article by dipping or spraying. It is then placed a vacuum chamber from which the air is extracted to noximately one-millionth of an atmosphere. The coating applied by "firing-off" aluminium from hot tungsten es while the article is rotated to ensurs an even coating I finish. A final protective coat of clear lacquer is applied,
and should a colour be desired, a suitable dye is introduced.
Some of the advantages claimed for the process over electro-plating are that the finish is non-tarnishing and needs no polishing, it is carried out in a dry state and is thus most suitable for applying a finish to plastics or glass, and colours can be freely used. In favourable cases, costs, too, may be reduced by half of the probable expense of electroplating.
Further information regarding the various applications or vacuum metallizing can be obtained from Dohm. Ltd., 167 Victoria Street., London, S.W.1.