TotalBoat Polyester Fairing Compound should not be applied over any 1-part primers. To maximize adhesion for all products involved in a fairing and paint job, perform all fairing processes before applying any paint or primer. One-part primers are designed to give paint the best substrate to bond to. This may not work as desired with a polyester-based fairing compound. Also, if paint was applied directly to the polyester fairing compound, it may not have the same bond as it would to the primer.