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Dirty Steel prior to Powder Paint Wash

July 8, 2008

I have a problem with my powder paint peeling off in strips of my Cold Rolled Steel within 2 weeks of being painted.
Our process is a
5 stage wash/rinse
Powder Paint (electrostatic)
433 degree oven for curing (Line speed is 15-18 minutes in the oven)

We tend to paint the parts and place them in baskets and store them outside until needed for use in assembly.

I noticed when I pulled the paint off in a large strip that there was rust under the paint.

Can you give me some advice?

Marie Dobbs
Quality - Worcester, Massachusetts

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Hi, Marie. The work may be passing through 5 stages of ostensible cleaning and pretreatment, but it's not being cleaned and pretreated :-)

Regards,

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
July , 2008

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I would really need to know your pretreatment process in detail to give any specific advice. Most of the problems I've run into when I am called to help companies is the lack off "process control". To many times something is out of control such as the chemical concentration percentage, the temperature or impingement. I am sure your chemical supplier can help you with this problem. Bob

Bob Utech Benson, Minnesota

Ed. note: Bob is the author of: "High Performance powder Coating" on eBay or AbeBooks or Amazon [affil links]

July 13, 2008