Motor Guard RB-3 Run Blocker, 3 Pack.
The Magna Run Blockers are engineered for the refinishing technician to block out runs, sags or dust particles in top coats. Also, they are ideally suited for block sanding body filler or primer in hard to sand areas resulting in a truly smooth finish.
Made of rugged, non-compressible aluminum alloy, they are designed to sand only the highest point of the run; eliminating waves that become visible after polishing - a common problem with ordinary rubber "hard blocks".
Here's How They Work! (Wet sand for best results):
1)Using a sheet of "wet or dry" sanding paper, single thickness, wrap it around the Run Blocker.
2)For larger runs or sags, "Break Open" the area with 400 or 600 grit paper and allow to cure.
3)Block the run almost level with 600 grit and apply a "guide" coat.
4)Finish leveling with ultra fine (1000 or 1200 grit) and polish the repair to its final gloss.