Dents or scratches on a car can severely ruin its appearance. Taking the car to a bodywork garage can be a costly and time-consuming experience. One process that is becoming increasingly popular and is a smart alternative is to use a personal airbrush and touch up the car at home. Although this takes practice and skill, it can be efficient and fun to learn how to do, and it's a relatively inexpensive way to cover car blemishes.
Wash your car completely. Do this at home or in jet car wash as opposed to an automatic one -- you need to have control over the cleaning process, spending ample time especially on the dents and scratches that you will be airbrushing. Remove any dirt that may have accumulated in the folds and scrapes.
Use a tack rag to further clean and dry the areas that will be airbrushed. Tack rags will help eliminate any build-up left on the car from other rags.
Test the paint that you wish to use to touch up your car. Spray it on a surface that is similar to the surface of your car and allow it to dry. Use your airbrush to test the paint out and practice spraying (always practice beforehand to get a better sense of feel for the airbrush and paint). Once the paint is dry, see that it matches the colour of the car that you will be touching up. Often, paint applied with an airbrush will be a specific colour when applied and then change to become brighter or darker after drying. Also, while practicing and testing, apply multiple layers of the paint to your scrap piece because the final colour may be enhanced with multiple coats. This is recommended when airbrushing the actual vehicle.
Mask the areas that you will be touching up. Apply masking or painting tape around the areas that you wish to retouch so that if the paint is accidentally sprayed onto that section, the tape will prevent splatter. To mask off larger areas, use paper or plastic sheets.
Wear a face mask and goggles as you work. Airbrush the primer onto the vehicle where you would like to retouch it. Using the sprayer is simple: hold the "gun" with your right hand (or vice versa if you are left-handed), and use your left hand to keep it on point and stable. Press the button or lever that is located on the top of the airbrush; usually you will be able to use your index finger to press it. Pressing the lever will open a valve and allow the air to flow from the pump through the hose and into the nozzle, pushing the primer out that is accumulated there. Depending on how hard you press the button, more or less air will flow out, which will mean a harder or softer spray of primer onto your vehicle. Use smooth, even strokes of the airbrush to apply the primer.
Allow the primer to dry completely and then sand it down -- first with 220-grit sandpaper and then 600-grit. This will smooth the strokes out and help the paint to adhere to the car. Wipe the primed area with a tack rag to get rid of any debris that gathered there while sanding.
Apply the paint that you have chosen as your vehicle's colour into the paint reservoir of the airbrush, and apply it to the primed area of your car. Use the same method as you did to apply the prime, keeping the spraying even, level and smooth. Once complete, allow the coat to dry completely.
Remove the masking tape. Once removed, reapply fresh masking to the areas that you don't want the paint to be sprayed onto. Do this remasking after every coat of paint to make sure that the paint doesn't seep under the tape and ruin areas that you don't want touched. When reapplying, make sure that the tape is not folded or buckled because this will cause paint leakage and the aforementioned problem.
Paint a second coat over the first. Let that sit and dry. Add a clear coat or glossy finish to your touch-up if your car's paint job requires it.