Painting a car with the conventional method of using a spray booth, a compressor and automotive paint is certainly the most effective and conventional method, but there are other ways. You can also paint a car by hand. By far one of the cheapest but effective methods is the roller paint job, where the paint is simply rolled on. With enough elbow grease, you can get outstanding results.
Wash the car thoroughly. Inspect the bodywork for small dents and scratches. If there is any major bodywork required, have a professional shop do the work if you do not have the know-how.
Sand down dents and dings small enough to be fixed with Bondo with 120-grit sandpaper. Mix the Bondo and apply it. Once it has dried, sand it down even with nearby areas with 80-grit, 120-grit and then 220-grit sandpaper.
Tape off the trim and any areas that you do not want to be painted. The nice thing about the roller paint job is that you do not have to apply large areas of paper since there is no overspray. Just apply 1 or 2 inches around the edge of anything you are masking off.
Sand all of the body panels with 220-grit sandpaper. Sand in the same direction.
Wipe the body panels off with white spirit. As you move from panel to panel with the paint, wipe the panels one more time with white spirit to ensure strong paint adhesion.
Dilute the Rust-Oleum 50/50 with white spirit. Pour the paint and the white spirit into a mixing bucket and stir well. Pour some paint into the paint tray.
Dip the high-density foam roller into the paint. You must use high-density foam rollers.
Roll the paint onto the car's panels, rolling one panel at a time. Smooth out any runs with the roller as they appear. Once you have rolled one layer of paint, let the paint dry for at least eight hours.
Sand the paint with 220-grit and then 400-grit sandpaper. You will be sanding away the orange peel, which is the textured finish left by the paint. Clean the panels with white spirit between every coat of paint.
Roll on another layer of paint, one panel at a time. Allow the paint to dry for at least eight hours and repeat the sanding and painting process. Repeat the rolling process until you have applied at least six or seven layers of paint. Eight or nine layers will really ensure enough coverage for the amount of paint that will be sanded off during the sanding process.
Once the final coat has been applied, sand with 400-grit, 600-grit, 800-grit, 1,000-grit and finally 1,500-grit or even 2000-grit paper. The paint will now have a very dull look, but don't worry.
Polish the paint with a high-speed orbital polisher with rubbing compound or machine glaze, available at auto parts stores or paint supply stores.
Polish the paint with a high-quality swirl removing polish. By now the paint should be looking pretty good.
Let the paint cure for a week and then polish it with a high-quality wax and the high-speed buffer. Reassemble any trim that was removed.
If you paint a car with Rust-Oleum and want to repaint it with conventional car paint, the car will have to be stripped to bare metal. This is because of the fish oils in the Rust-Oleum.