I bought a 98 chevy z71 that was wrecked in the front end. I had some used fenders and hood that I put on the truck, I fixed the bad spots, primed them and then blocked the entirecab foward. In a few spots the paint blistered, I think, It looked like the paint cracked. What happened?? Any way I spent the day blocking it down again, someone suggested that I seal those areas with some primer/sealer. hen I have seen the sealer on stuff before It looked rough and I figure that will show through the paint being rough.
Please give some insight

Thanks to all

ttt anyone??