I put a single coat of Pre-Kote primer on yesterday afternoon and can't seem to sand it off without causing more problems. The problem probably stems from the fact that I did not thin it when applying it to the hull, so it's probably a thicker coat than desired, but I get about 5 seconds (literally) out of a 120 grit disc before it gums up and doesn't cut anymore.
I tried cleaning and re-using the discs, 80 grit, 220 grit, a sanding block with all of the above and even sheet rock mesh . . . all to no avail.
I'm plowing thru, but I fear I'm causing more damage than good (cut thru epoxy in a couple of small places) and it's costing a fortune in discs. At this point I just want the crap off my boat.