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Cadmium plating
Recently, I bought a tub of cadmium plated nuts, bolts and washers. These have a pleasant, soft colour and looks far better than the zinc plate, which looks too bright, on older machines. All the specialist platers I’ve tried don’t do cadmium plate and tell me zinc plate serves the same role and looks similar. It doesn’t. Is this a case of zinc plate is more cost effective to the platers and they don’t want to bother with cadmium plate? Or am I missing the point here?
Cy Aldridge, email, West Country.
The glib answer, Cy, is that you are missing the point, but in fairness to you and all who would like cadmium plated fasteners and detail parts, it’s a pity at least one of the platers you approached for this service didn’t tell you the reason why they can’t – rather than won’t – carry out cadmium plating for you.
Background first. During the vintage period (1920s) it was discovered thin coatings of cadmium applied predominantly to ferrous components (it was applied to other metals, especially for the aero industry) had excellent anti-corrosion properties, even in salt-laden environments. Previously, dull unpolished, soft nickel plate served a similar role, but cadmium plate proved to have a much better corrosion resistance than dull nickel, although thicker applications of dull nickel improve its anti-corrosion performance.
Apart from our older motorcycles, cadmium plating gained near universal popularity for aircraft components, military applications
