Do I need to use a primer when painting formica countertops?

Painting Formica countertops is almost mandatory because you will be using a high-grit belt sander and 150-grit paper, so no amount of washing and wiping and vacuuming will take care of all of the little grooves. The best bet, then, is to use a complete Krylon paint kit, starting with the primer – four coats, individually and allowing them to dry so that you can then apply the gloss or semi-gloss finish paint properly. You can then either apply the sealer coat in between applications of the finish coat or you can apply four layers of finish coat and then use four layers of sealer.