For people who love their cars (and who doesn't?), nicks and scratches are looked at as a personal affront. Unfortunately, scratches and nicks are inevitable, especially those referred to as “rock nicks” which come from rock chips ricocheting from the road to the bottom parts of today's low-slung cars. Small scratches and nicks, if not attended to at once become bigger as the paint around a scratch starts to chip and peel off. Oxidation sets in and causes more serious damage to the paint job and the car's body.
Paint jobs in auto shops to repair nicks and scratches can be criminally expensive. In many cases, the shop will insist on repainting the entire panel instead of just the tiny nicks and scratches. This makes a DIY job a very attractive alternative for car owners.
Here's where the airbrush comes to the rescue. A Single-Action Bottom Feed internal mix airbrush with a hobbyist compressor should be able to do the job for small nicks and scratches. A hobbyist compressor is a small compressor used mainly for airbrushing model cars, planes and other small items. A 5 hp compressor delivering 6.2 cfm at 115 psi will suffice. If the nicks and scratches are fairly shallow, the procedure should be quite simple.
The area around the nick must be washed and cleaned with soap and water, not detergent, and free of grease and dirt. Then, it should be lightly sanded using a rubbing compound or fine sandpaper, then wiped clean with denatured alcohol. After applying a small amount of auto primer, the first coat of paint is airbrushed on the area and allowed to dry. A second coat of paint is then airbrushed, allowed to dry then smoothened with a rubbing compound.
If the nicks and scratches are deeper or are spread over a wider area, a retouching method known as Small Area Repair Technique (SMART) is recommended. A Single-Action Bottom Feed external mix airbrush should be used.
The area to be painted must be washed and cleaned, then sanded with ultra-fine sandpaper dampened slightly with water. An area of 4 inches around each nick must be sanded, and the whole area wiped clean with a solvent-based degreaser. The parts which will not be painted should be covered with masking tape.
From a distance of 4 inches, three coats of paint should be airbrushed over the nicks. Each coat dry must be left to dry for about 10 minutes before the next one is airbrushed. The last coat should be sprayed beyond the edges of the first two coats. After emptying the airbrush cup of paint and filling it with blending thinner, he thinner is mixed with the paint residue in the cup and the mixture airbrushed over the final coat of paint. After letting the paint dry, preferably overnight, the new paint should be blended into the existing paint work using cutting compound on a piece of mutton cloth.
An important consideration is choosing the right color of the paint. The exact color code is printed in the owner's manual, or can be found in the data plate located in some place in the car. In case this information cannot be located, the local car dealer should be able to provide it.