The body’s three coats of primer had been block sanded with 320-grit
paper using a board file. Each time he sanded, Townsend shifted the
direction of his passes with the sand paper, but always kept the direction
at an angle — there were no completely vertical or horizontal
movements with the sandpaper. This and the following steps removed
any orange peel in the primer.
Townsend then moved to a finer-grit 400 sandpaper. He hand-sanded
edges and concave areas carefully with sandpaper on a rubber or foam
block that flexed with the car body’s contours, then used a 400-grit
sanding disc attached to a dual-action sander for the larger, flat surfaces.
For the third sanding, Townsend finally moved down to 600-grit and
wet-sanded the body.
Flexible sanding blocks are used at edges and in areas with
character, such as the concave depressions on the side of a
Mustang.