keep the painted surface wet while sanding.The same sanding direction is carried through from top to bottom,
even though sanding is done in sections. Each area that is sanded
overlaps adjacent sections to ensure an even finish.His first pass uses 800-grit water-soaked wet or dry automotive sand
paper attached to contoured rubber sanding blocks on the painted
surface, which has been made wet with a spray bottle. He picks a
comfortable angle in which to sand the length of the panel. Once he
completes the pass, he cleans the surface again, then repeats the sanding
at an opposite angle (90 degrees) from the first pass in a method he calls
cross-cutting.