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How to avoid defects in Powder coating (Epoxy) on CRCA Sheets?

July 31, 2009

Dear All,
We are using 7 tank process for powder coating, Usually we use a very good quality epoxy powder. we usually coat on CRCA sheets. Kindly help us in avoiding the following defects & others if any.
1. Orange peel defect
2. Unevenness in p c, at edges the coating will be thick.
3. Burrs or pimples on powder coated surface

Your thoughts will be highly appreciated

Best Regards,

Mallikarjun Patil
Plant incharge - Daman, INDIA

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 July 31, 2009

You state that you use a good quality epoxy powder it sounds as though you should change suppliers as their technical field expertise is no where as good as their powder; why no technical visit? Answering this type of problem is so difficult without a visit. Anyway here goes:
1. Orange peel defect. Good epoxy powders have excellent flow try a competitor's powder. Check that the entrance temp to oven not too high.
2. Unevenness in p c, at edges the coating will be thick. This is a normal phenomenon with ALL powders due to the first powder traveling towards the earthed item always goes to the edges. Try different application techniques.
3. Burrs or pimples on powder coated surface. Could be out gassing, bits falling on semi cured powder in the oven so many other ways. That is why you require an on-site visit.

Terry Hickling
Birmingham, United Kingdom

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Thank you Terry, every time you do a great job ha...
please continue, you give a valuable inputs.

Mallikarjun Patil
- Daman, India
August 6, 2009