Q. We plate brass on zinc castings, but after we lacquer and bake the parts, the brass seemed to disappear. What’s going on?—S.P.
A. Brass is composed of copper and zinc. It sounds like the copper component simply migrated into your zinc casting, resulting in “disappearing brass.” I assume you did not put a copper strike on the zinc die casting before plating with brass. You should do this. You might also consider a thin layer of bright nickel over the copper before brass plating. This procedure also should improve the appearance of the brass plate.