I like to refinish woodwork, sometimes stain grade but most of the time paint grade. I use Zinsser Coverstain (the waterbased one because I am in CA) and I really like it as far as dry time, stain blocking, sealing ability, preventing flashing, stopping sap seepage, etc. I will often use a coat of Coverstain, then putty, then sand, then another coat of Coverstain, repeat, etc. I typically use Ready Patch for small cracks and fills (for larger repairs I use epoxy-based stuff.) My system is pretty okay, except for sanding.

Sandpaper clogging is my big PITA. I can sand with 80 grit okay, but if I go to 120 grit my paper clogs so fast. It doesn't matter if I am hand sanding, ROS, 1/4sheet finish sander. My paper seems to clog so fast no matter how long I let the primer and putty dry.

Am I missing something about sanding? Is this normal? Should 120 grit clog after a few strokes on dry primer?

I have tried a couple different primers that sanded about the same, but don't have the other good qualities I am after.

Any suggestions?