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Powder coating on yellow chem film

I have trouble with yellow chem film discoloring after powder coating.What are the temperature ranges that chem film can obtain before having problems?

Dennis McFadden
- Dallas, Texas
2003

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First we have to assume you are using "clear" powder coat if you can see the chromate under the coating. Mil Spec requirement for bare aluminum chromate is not to exceed 140 F as high temperature dehydrates the coating. Generally under paint you may cure higher than 140F, however, powder paint is cured much higher. If the chromate is too thick it will breakdown at powder coating temperatures. For powder coat prep always put the chromate on very light (thin).

Robert H Probert
Robert H Probert Technical Services

Garner, North Carolina

2003

I met same problem six months ago. According to my experience, this problem was caused by the yellow chromate process. Please pay more attention to your yellow chromate process. I'm sorry I can't give you suggestions regarding chromate process due to this process being accomplished by our sub-contractor.

Steven Gao
- China
2003