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Request for help gold Alodine

We have been experiencing problems powder coating aluminum parts which have been plated with gold Alodine/yellow Iridite. The plating is being subcontracted. We have a three stage washer - wash/iron phosphate, water rinse, final water rinse. We have noticed recently that the gold color has been coming out in the wash. Sometimes it is the entire part but more often it is an area on the parts. Our washer chemical supplier suspects the plating is not being done correctly. Any suggestions would be greatly appreciated.

Tom Kerbaugh
Precision sheet metal job shop - Cinnaminson, New Jersey
2003

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I was not aware that you would run Alodined aluminum thru a phosphate prep prior to paint. None of our customers that painted did. Depending on the pH and the temperature of the prep process, it would not surprise me that the chromate coating would be coming "loose".

James Watts
- Navarre, Florida
2003

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2003

HI,

TELL YOUR SUBCONTRACTOR TO DO AS FOLLOWS.

1-USE GUARANTEED CHEMICAL OF YELLOW CHROMATE'
2-WASH WELL AFTER CHROMATING IN ORDER Cr6+ TO BE REMOVED.
3-AFTER WELL WASHING DRY BY FAN AND HEATER NOT OVER 50 °C.
4-AFTER STEP 3 START POWDER COATING AS SOON AS POSSIBLE.

Hadi Khosravi
- Tehran, Iran