When there are problems in the paint finish, all direction is often lost on how to troubleshoot. Whether you have fish eyes (moon craters), hairs, lint, specks, or bumps, take your time. You must keep notes during any type of troubleshooting.
Start with coating test panels. These test panels must not be homemade from metal at your manufacturing location, but from an outside source which makes special test and sample panels. You can never eliminate the possibility the problem could be your metal! These test panels are now going to be exposed to each and every step in your finishing system, one step at a time. Remember, keep notes.
Start by coating your first panel at the spray booth. Write a number, letter, or a date, in the powder on the panel before it is cured in the oven. This type of a note is permanent and will eliminate panel mix-up. If the panel looks OK, then the problem is not in the spray booth, equipment, or powder.
Now back up another step in your finishing process. This could be the final rinse step in the washer. Dip a new test panel into the rinse tank of the washer, and dry it in your dry-off oven, coat it, mark it, and cure it. Now, how does it look? If OK then back up another step until the problem is found and corrected.
One final note, "Silicon" in a lubricant form and in a quantity as little as one part per million, will cause fish eyes (moon craters). It will not wash off in the washer but degreasing is better. It can come from a new wonder if being used in your air compressor. It also can come from the welding equipment where the nozzles are now being cleaned with a new anti-clog spray. The most amazing find of silicon was its use in sewing tread, as a lubricant. A small amount of this thread was then used to sew end splices to a filter belt used in a filter belt type spray booth. After two weeks of 80% rejects and 3,000 lb of wasted powder, the problem still remained. The filter belt was then replaced with a silicon-free belt. Fresh powder then solved the problem.