Estes Bullpup Build Part 8, Primer and Paint Sand

After lightly sanding down the gray primer you can see the primer left in the gain pores.

A light coat of gloss white followed.

Hold the surfaces under a bright light and you can see some rough spots.
Lightly sand these spots with 400 grit, dry.
Don't wet sand yet, the paint cover isn't thick enough. The water might get down into the tube and balsa.

This is the same fin after lightly sanding the first light coat of white.

When sanding between coats you just want to dull the surface. You won't need to sand off all the paint.