A term some of you may have heard of is a guide coat. This 67 Camaro is in the final steps to prepare it for paint. Click on continue reading to understand what a guide coat is and how we use it to achieve a show quality finish on this, or your classic car.
NOTE: You can click on any of the photos in this article to see a full size version.
A guide coat is a very thin layer of paint applied to an opposing color of the primer coat. This is done when preparing a car for final paint. The 1967 Chevrolet Camaro pictured here is getting a top quality, show winning finish. That means the panels have to be perfectly straight. This is the step in the process where we use a guide coat. Typically we use a black guide coat over the gray primer. After the guide coat is applied, we will use long sanding blocks to sand the guide coat off. What will happen is that the guide coat will sand off of the high spots, and will stay in place in any low spots.
This will allow us to see any imperfections. If the low spots are low enough we will use a glaze to very lightly build up the surface. Then we will prime, sand and guide coat again. If the low spots are very small we may just use a coat of filler primer (this is a heavier form of primer that helps fill in scratches & surface imperfections and is designed to be sanded to help even out panels). Of course, more sanding continues after filler primer.
We will repeat this process until the panels of the car are "laser" straight. This is most important with dark color cars, especially black. Since dark colors reflect more of the surroundings it is easier to see imperfections or waves in a body. Using guide coats is crucial to getting body panels as straight as possible before we lay down any color on the car.