Used gun and it was rock hard in a day.http://forums.pelicanparts.com/uploa...1381988095.jpg
http://forums.pelicanparts.com/uploa...1381988160.jpg

Worked perfectly. I sprayed it over when the POR15 when the POR was only a couple of hours old. Having said that, I thought I was doing as per instructions.

I have no idea I just followed the POR 15 instructions. I suspect it is to insure sticking between different paint types and i suspect that POR 15 does not play well with others. Whatever, it seems to work perfectly

Correct. If you want to put a top coat on POR-15, do it while the POR-15 is still tacky. When it is fully dry it becomes a mirror-like finish which is hard to get anything to adhere to unless you scuff it up first. Painting over it while it is still tacky is the easiest solution (at least in my experience).

Good news is that once dry it is as tough as old boots. In one area where the POR15 had been n for a while I literally used a wire brush in my drill to scruff it up before applying a second coat. Once again worked perfectly. I'm a great fan of POR15.