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Need help with CARC paint question

I am the QA Manager for a power supply company that designs and manufactures power supplies for military use. We have been building a particular power supply that requires CARC paint. For the past 4 years there has been no paint issues. Until now. I was contacted by the customers QA telling me the covers of the units were not CARC paint. They are testing the paint with acetone [on eBay or Amazon] and paper towels. They apply the acetone to the paper towels and rub hard for 10 seconds. They repeated this test a number of times. The paper towels still showing paint residue. Is there a documented method of testing the paint to make sure it is CARC? I know the paint is chemical resistant, but is using the paper towels too abrasive? I used the acetone method but with non-abrasive wipes. The first wipes did show green, but it eventually faded and the paint on the cover didn't seem affected.

Andrea Barnes
Electronics Manufacturing - San Jose, California, USA
2004

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Just a thought... Are these covers hung lower than the rest of the unit or are they heavier gauge material? My thought is that the last property that develops in a cure cycle is the full cross link responsible for chemical resistance. If these parts are not quite as fully cured as they should be it could cause this problem. The acetone rub test is good even with paper towels, but you should have on-hand a known-good panel for comparison. CARC Paints should not be affected by the acetone, but curing agents or other surface contaminants may show up on the rubbing cloth.

I hope that's helpful,

Jeff Watson
- Pearland, Texas
2004