Arcing In A Barrel

We find that when we plate lightweight parts with sharp edges, a significant number will have burned areas. What is causing this?


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Q. We barrel plate using a cyanide zinc plating solution. We find that when we plate lightweight parts with sharp edges, a significant number will have burned
areas. What is causing this? V. F.

 

A. My best guess here is that the parts are ‘floating” in the barrel. If the parts float in the barrel and do not make electrical contact, you have a smaller number of parts carrying the current.

A smaller number of parts carrying the current means higher current density, and you end up with parts that are burned.
Some things you should try in order to eliminate the problem are as follows:

  1. Reduce the size of the load in the barrel.
  2. Add heavier, larger parts in the barrel so that better electrical contact is made. The larger, heavier parts should be ones that can be easily separated from the smaller lighter parts.
  3. Try to improve your electrical contact with the load of parts. You might try using button contacts instead of a dangler.
  4. Reduce the current flow. This means that each load of parts will have to be plated longer but arcing should decrease or disappear.

 

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