Well, right now, I'm painting my valve cover. and I got it off, used aircraft stripper, sanded & wet-sanded it with 320grit. Then I thought that I don’t want to have those "sanding scratches" in it, so I stepped up to 600 grit. Now, when I look at it under light, it looks finely scratched head on, but feels REALLY smooth, and almost has a reflection on the flat parts when you look at it at a 30deg. angle. I bought some white plasti-kote engine enamel, (1000 degree) and it does not require primer, but I was wondering if I perhaps sanded the bare aluminum down too smooth? Should I go back over it with 320 grit again so the paint sticks better?