Touch up of Zinc Chromate Finished Steel

I restore old radio equipment as a hobby and I am frequently faced with a vexing problem. Equipment from the 1950's and 1960's with steel chassis that have been yellow zinc chromate finished frequently have pits and small rust spots. While I certainly can remove the rust without much of a problem, I also remove the finish at the same time. With complex pieces of equipment it is impossible to strip the chassis and have the piece refinished. Is there a touch up kit that will do a "reasonable" repair on yellow chromate finished steel? If yes, is this solution as toxic as the cyanide based products of 30 years ago?

I'm personally not much in favor of plating except in an industrial environment but, yes, there are brush-plating kits you could use to zinc plate from a cyanide-free electrolyte and then yellow chromate. Vendors in our Directory include Gold Touch, LDC, and Sifco.

Ted Mooney, P.E. RET finishing.com Brick, New Jersey