Testing over Fisheyes

Question:

My question involves coated test panels. We were conducting some testing on our wet spray conveyorized line and started to notice an intermittent fisheye problem, even after the panels had been solvent-wiped with MEK. To make a long story short, we had our suspicions and found out that some contractors had been in to repair the factory air compressors. These contractors have long since been lined up and shot at sunrise, but while they were here, they used a silicone-based gasket material and sealer for the compressor. We have since taken steps to correct the contamination problem. The fisheye problem was not severe, that is, only a few panels had them, and we noticed that some smaller fisheyes repaired themselves as the coating leveled and flowed. The painters planned on scrapping the panels with noticeable fisheyes after curing. Their question to me was whether they should also scrap the panels that had fisheyes at the time of application, but not after curing.

My answer was that they should note the problem and specific panels for future reference and continue with their testing. I thought that as long as the film was intact and that the thickness was correct, the former fisheyes would not present a problem. Although there was probably a small silicone particle somewhere in the cured film, I did not feel that was reason enough for discarding the panels, as long as the situation was noted. If a problem was observed during testing that could be attributable to the fisheye, then we would know. I also recommended that they test the panels that had fisheyes and would not be affected by this condition. My question for you is, am I off base and should I have told them to scrap everything and start over? M.D.

Answer:

I agree with your decision. In the past, I may have said start over, but owning to the time involved in making test panels and the effect on production schedules, we can make allowances. The most important part of your decision is noting the affected panels and using bad panels only for non-critical tests. On the other hand, painted products with film defects should never be allowed to leave the paint application area.