As mentioned in Article 7 on bodywork, Jim Mokwa had his GTO's body professionally repaired by old-time body man Leo Coonen of Waupaca, Wis. Even though Jim had used Leo to fix other cars, he admits that the cost on the Resto-Mod GTO ran higher than he expected. Jeff Noll saved some money by doing the bodywork on his Camaro by himself. Each panel on Jeff's car was primed, sanded and re-primed before Jeff started his final preparation for paint.
Each panel on Jeff's Camaro was primed, sanded and re-primed before Jeff started his final preparation for paint.
Primers are spray on or brush on coatings that are applied directly over unfinished metal (or over fiberglass or metal body fillers). There are different types of primers, each intended for different purposes. Primers are not made to serve as a topcoat, such as a paint or powder coat. They are meant to be used only to prepare the surface that is going to be painted to accept the paint. Resto-Mod builders will find themselves dealing mainly with three types of primers: 1) Epoxy primers; 2) primer-surfacers (also known as primer-fillers) and sealers.
Primers spray or brush on directly over unfinished metal, like the new floor in Jim Mokwa's GTO, to protect it from rust.
Waterproof epoxy primers serve to protect bare metal from the process of oxidation. You mix these products with an activator that starts a hardening process over a certain period of time. Each product has its own "window" of time in which you can spray it on the car before it hardens. Because the epoxy primers are waterproof, they'll protect the bare metal from rust. In addition, they are formulated to help the new paint that you'll put on over them adhere better to the metal. In most cases, the epoxy primer will be a part of the paint system you purchase and will be a product of the company that manufactured your paint. Usually, you'll be applying one or two coats of epoxy primer during your builds.
The rear floor and both the horizontal and vertical underseat areas in the GTO ragtop's rear passenger compartment were prime coated.
Most Resto-Mods are build from older muscle cars on which sheet metal made in the '60s or '70s has been repaired to one degree or another. Even when expertly completed, such repairs often leave very minor signs of filing, sanding, hammering and riveting. Primer-surfacers are used to "hide the evidence" of body repairs. These undercoats are blended with a high enough level of solid pigments to fill in the microscopic scratches and pinholes to provide an exceptionally smooth surface for the final topcoat (or paint) to be applied over.
Correctly-applied primer-surfacers can fill in flaws up to 1/4-inch deep. Jeff Noll used these products on the new rear quarter panels he welded onto his car.
When used according to instructions, primer-surfacers will fill in flaws that are up to 1/4-inch deep. They do not replace the use of body filler that is used for heavier repairs. The primer-surfacers are not strong enough to fill areas larger than those they are designed to fix. However, they are one of the keys to a perfect paint job, since the final topcoat serves to emphasize what's below it.