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Ted Mooney, P.E. RET
Pine Beach, NJ

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Paint peels off from AL6061 casting

I have a problem with an aluminium part that we paint without using cromatic coating due to some requirement from the USG contracts. So far no problem after many parts . . . but suddenly 4 parts the paint peels off. Please advice

56634

Natan Cohen
- Israel
February 2, 2011

Hi, Natan.

If anyone has started using a silicone release agent, or silicone anywhere, your pretreatment cycle cannot remove it. It's almost impossible to remove. Please study whether silicone got into the sequence somehow. Good luck.

Regards,

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
February 2, 2011

If I understand you correctly, you don't use a chromate conversion coating as it is restricted. Hex chrome is a big NO NO but you have to use a trichrome conversion coating instead of it. You cannot paint Aluminum with no conversion under at all.

Sara Michaeli
Tel-Aviv-Yafo, Israel
February 22, 2011

If no Chromate is allowed you can use a Wash Primer before you prime and paint.

Mike Nelson
- Chattanooga, Tennessee, USA
February 23, 2011

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