Arcing In A Barrel

Q: We barrel plate parts in a barrel using a zinc cyanide solution. When we plate stamped parts made of light gage material some of the parts are burned on the surfaces. We do not have this with heavier parts.

A: It seems to me that the key to the solving of this problem is your observation that you only have this issue when plating light gage stamped products. The parts because of their lightweight are probably not making good electrical contact in the barrel. Putting this another way, some of the parts are probably “floating” in the barrel and not making good contact. With poor contact they will not carry the current correctly and the arcing you observe is the result.

I would start out by trying to improve electrical contact in the barrel. Button contacts may work better than conventional danglers. You should also investigate reducing the current to the barrel. An old trick that sometimes works is to mix two different size parts in the barrel. Of course, this approach requires that the two different parts can be easily separated. Try experimenting using a smaller load in the barrel. If you are able to change the rate of rotation of the barrel experiment with different rotation rates.