Zinc and Cadmium Plating

Quite a while ago, I bought some plating kits from Caswell Plating.  Among them was a zinc and copy cad kit.  This actually plates with zinc, but depending on the original surface, the final product can look a lot like cadmium plating.

The process is quite straight forward.  The part has to be clean, free of rust and any grease.  Glass beading is best for a matte surface so it will look like cadmium plating.  Then you soak it in a SP degreaser followed by a fresh water rinse.

The kit I have is a 3/4 gallon, designed to be used in a 1 gallon plastic container.  It requires a small AC/DC adaptor (good for ~12 square inches) and an aerator (aquarium air pump).

The bath is an acid solution.  A zinc plate (or two) is the anode, while the object being plated is the cathode.  The electric current removes zinc atoms from the sacrificial plate and deposits them onto the object.  The first time, you plate a sample piece to purify the system.  Here I'm using some sheet metal for that purpose.

You wire the objects and hang them from a bar in the solution.  On the left, you can see another piece of zinc hanging from the bar.  This is used when the surface area of what you are plating is not close to the 12 square inches.  You submerge as much of the zinc strip as needed to total the 12 inches.  You can see some effervescence near the wires hanging from the bar.  This is caused from bubbles being formed during the chemical process and a good indication that something is happening.

My first couple of items weren't as good as I wished for.  The plating on the switch and tab were OK, but the hood catch didn't work as well.

I didn't do any more items until I was working on the carbs.  There were several items that needed silver cad plating, so I tried again, with much better success.  Here you can see the parts just after the plating.

The results are not as good as professional cadmium plating, but this can be done in a couple of hours (actual plating time is 5-15 minutes).