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  for Metal Finishing since 1989
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Process to blacken hard chrome plating

1996

I am in search of a simple process (such as a room temperature blackener) for blackening hard chrome plating.

I would also like to hear of any way to cosmetically or functionally repair small pits in a chrome plated shaft without going through the time and expense of stripping and replating.

Does any one out there have any ideas?

Tom [surname deleted for privacy by Editor]

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Sorry, I know of no way to blacken chrome except by applying black chrome, Tom.

Pits are virtually always the result of poor surface preparation, not problems during plating, and cannot be repaired. The thing to do is to fix the preparation process and make the pitting problem go away forever, rather than trying to fill the pits with chrome, chewing gum, or anything else.

Give contact Dr. Allen Jones at Atotech. He has a wonderful paper he will send you that details his findings on the causes and preventions of these pits. Simple stuff like not reusing emery cloth.

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
1996