I seem to get nowhere on these body panels, every time I sand I get pinholes in the primer itself, not where it has body filler. Its a high sandable primer by U-Pol. I can never finish a panel, they keep popping up. What causes this? I have yet to set up my compressor with all the water separators that I plan to use with the base coat, perhaps it's water? I dunno. Thx
