Hey everyone. I applied three coats of self-etching primer to my engine bay tonight , and i had a whold bunch of runs(i'm not the best painter and that stuff is thin). I want to block sand those out before i put the other primer on, so what grit sandpaper should i use. Thanks.
aaron

I'm no expert, but I'd guess 120.

I would wet sand and start with 400. make sure you use a block and not your hand because it is not even pressure. Do you have a squeegy? Somthing to get the old water out of the way. the best way to paint it to not stay in on place, keep the nozzle the same distance from the surface at all times. And do steady even strokes. not much else I can say without showing.

You can dry sand, but try to keep the sand paper clean, ie old primer. 120 is too low, 400-600 works great. But cloged paper would be like sanding with toliet paper!!