TotalBoat 2-Part Epoxy Primer should cure for at least 5-7 days at minimum under proper curing conditions prior to applying any gelcoat to the surface. Though the epoxy primer may be tack-free in a number of hours, it must be completely through-cured to an inert state, which may take up to a week under normal curing conditions.
The cured epoxy primer must be sanded, and any sanding residue removed prior to applying any gelcoat materials.