Coat the abraded plastic with acrylic spray primer. Spray in a sweeping, side-to-side motion. Maintain a distance of 8 inches between the plastic and the spray nozzle as you apply. Wait three hours for the primer to dry.oat the abraded plastic with acrylic spray primer. Spray in a sweeping, side-to-side motion. Maintain a distance of 8 inches between the plastic and the spray nozzle as you apply. Wait three hours for the primer to dry.