What Kinds of Paint Are Used for an Auto Body?

Painting automotive bodies requires a bit of understanding with regards to how paint works on metal surfaces. Sure, you could just whip out a rattle-can paint from your local hardware store, but you're not going to get anything close to a professional finish that you see on new cars or restored vehicles.

Primer

For decades, primer has been the essential base coat of paint on a vehicle metal surface. The primer is critical because it etches the metal and prepares an absorbent surface for subsequent paint layers to cling to and adhere. Not using primer is setting up your project for failure, because base color variations will show through and your top paint will need extra coats to cover up blemishes.

Professional Spray Paint

Most automotive colors and paint are applied via a compressed-air spray gun in a paint booth for consistent, even application. This is critical because paint has a bad habit of dripping and running when too much is applied in the same spot too soon. It can also wrinkle and separate from the target surface when wet/dry and repainted too much. The result looks like the surface of an orange peel.

Top Coat or Clear Coat

Sprayed-on paint by itself is still vulnerable to the simplest of dings or rubs, not to mention scratches. So painters use what is called a "top coat" or "clear coat" paint to provide a barrier that protects the color and prevents basic wear and tear on the paint. The clear coat paint goes on literally clear, without color, and adheres as a film over the colored paint. The end result is a glossy finish with the color paint protected underneath.

Powder Coating

Powder coating is an entirely different automotive paint approach, and it doesn't require primer. Instead, the automotive parts are stripped down to their bare metal. Sandblasting or media blasting is necessary to clean the metal completely. No residue is allowed, because it will cause problems with the paint. Further, any critical parts such as cavities, screws and threading need to be covered up with tap or gummy rubber prior to painting.

When actually painting, the powder coat paint is electrostatically applied to the metal part. The part is then inserted into an oven where the paint is baked onto and into the metal skin. The result is a thick paint skin that is much more durable to bumps and dings than sprayed-on paint. However, to repaint in the future, you will need to completely sand down the part to bare metal again. So this option requires some commitment to the color chosen.

Rattle-Can

Rattle-can painting is probably the cheapest, most amateur approach to auto painting. That said, some painters can produce amazing jobs with experience and a paint can. For the most part, both primer and colored auto paint are provided in a spray can that uses an aerosol pressure to project the paint at a target as a spray. This approach is most people's first experience at applying paint, and with cars the result tends to look very much like a home garage job.