Can any of you guys give me tips on paint prep? I'm using my electric sander with 80 grit to get rid of the cheap Maaco paint job that was done, then I'm going to move up grits and block the rest. What grit should I go up to before primer? I was looking at cheap guns at Harbor Freight and was wondering if they would be okay for spraying primer. What do you guys think? Any input is appreciated!