Painting Your Car - A Work of Art - Tech

Spray booths filter all sorts of dirt from landing on the painting surface. A spray booth can have positive pressure, meaning that the air inside of the booth wants to push outward, or negative pressure, meaning the air on the outside wants to come in. The best is a balance between the two.

Color-coat spraying techniques vary based on the type of paint being sprayed, the weather, the shape and size of the car, how wet the paint is lying down, and the spray gun. Most painters agree it is best to spray the entire length of the car at a time. This is done so that the paint can go on seamlessly and wet.

After the color coat of a two-stage paint system is applied, the clearcoat follows. Depending on temperature in the booth, the clearcoat should be applied about 20-30 minutes after the basecoat. Sometimes a small imperfection in the basecoat can be lightly sanded with fine-grit sandpaper before the final clearcoat.

After the paint job is completed and dried, it's time to make it shine. For many jobs (depending on the paint system used), several products are required. The general list includes 1,500-, 2,000-, or 3,000-grit sandpaper, rubbing compound, polishing compound, swirl remover, a rotary buffer, carnauba wax, very soft towels, water, and a variety of clean buffing pads. This process is called color-sanding and buffing, and it begins by lightly sanding the entire car with very fine sandpaper.

With a wet terry-cloth towel to keep the working surface wet, sand the clearcoat with fine-grit sandpaper on a buffing pad. Do the entire car just until the surface is dull. Be very careful on body corners, because the extra pressures localized on a smaller area will sand the paint down quickly past the clearcoat and even past the color coat to the primer or metal. To minimize the risk of this, apply low-adhesion masking tape (typically blue) over all the edges and corners before working in those areas.

After the entire car has been color-sanded, it is time to buff the car with a rotary buffer. Care must be taken not to allow the buffer to linger in one area too long and remove too much clear and paint or even heat up the paint and burn it. As with sandpaper, begin with the coarsest pad and work through the steps to the smoothest pad. Before using the buffer, note that you'll want to drape the power cord over your dominant arm so that it rests away from the path of the spinning wheel.

With everything ready, turn on the buffer and work it back and forth while traveling off to one side. Add compound as needed and work in about 2-foot squares. After a section about the size of the trunk lid is completed, lay the buffer upside down so the pad does not touch the ground. If it does, thoroughly clean it so no small rocks or debris will be buffed across the new paint. After each section is complete, remove the compound with terry cloth and continue the process across the entire car.

Next change the pad to the middle-grade and apply the swirl remover to the car while completing the same process across the entire car. Now attach the finest pad to the rotary buffer and apply carnauba wax over the entire car. Finally, with the soft terry-cloth towels, remove and hand-buff any residue from the finish.