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  for Metal Finishing since 1989
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Powder coating: Contamination of white powder

We are having a contamination problem only when we use white powder. We have tried several manufacturers.

We are finding pinholeing on the tops of parts after about an hour of running, then it stops then it starts up again.

We have tried cleaning our washers and oven ducts the problem still persists. It is on both lines and has occurred with different batches of powder as well as different manufacturers of powder.

KENNETH S [last name deleted for privacy by Editor]
- Chicago, Illinois
1996

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1996

Try isolating the contamination by coating some parts that are solvent wiped only, which eliminates the washer and dry-off, some parts coated with a hand gun using a different source of air, and some parts run through your system but pulled before paint and painted somewhere else. All this will help you locate the source of your problem, and give you clues as to the cause. Being only on the tops of the parts it sounds like either an airborne contaminant in your plant air or your parts are hung too high in your washer and not getting cleaned or rinsed properly. When you find out the cause let us know what it was, I'm always interested.

Good Luck,

Jeff Watson
- Pearland, Texas