White stains in nickel plating of pendants

Q. We produce gold plated jewelry. Prior to Gold plating we perform the following process:
- Polishing using a motor/lathe and buffing compound
- Electrocleaning with a Buffing compound remover
- Electrocleaning with al alkaline degrease (6v)
- Nickel plating (3 v)
- Gold plating (6 v)

The problem is that we have some white stains in the borders of the pendants. I have modified almost each variables of the process but still have the stains.

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March 26, 2017

A. Hi Rafael,
I am not sure I understand your question because the title mentions stains on nickel but your post mentions gold as well. Are the stains on the gold or do you see problems prior to Au plate?

Blake Kneedler
Feather Hollow Eng. - Stockton, California

Q. Hi Blake. We are having "white" stains in the edges of the jewels during the nickel plating. It is just in the edges. I do not know if the problem is in the previous electro-cleaning process or during the nickel bath. I have pics of these edges:

A. Hi Rafael. Although it's hard to photograph brightwork, so pictures can be hard to read, this looks & sounds like classic "burning" to me -- that is, the edges are receiving excessive current density, beyond that at which satisfactory plating can occur. More agitation may help, but unfortunately you may need to lower current (voltage) and plate slower. Good luck.

Regards,

Ted Mooney, P.E. RET
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
Ted is available for instant help
or longer-term assistance.
June 2017