Preparing the surface is the most important part of painting a car. From dent removal to rust repair, prep work must be done before you paint so your car will look as good as new. Here are some tips to help you prepare a car surface for painting.
Fill in any dents first. If you can pull out the dent, try using a suction cup device like glass workers use. If you don't have access to that, lightly tap the dent from the backside to pop it out as much as possible. Fillers will be used to fill in the dents, and the smallest amount used is the best. Polyester filler is recommended over plastic filler. Fiberglass can be used to fill in larger dents. Apply the filler in thin coats, about 1/8 inch thick for each coat. Sand with very fine sandpaper before applying the next coat of filler. Examine the surface closely to look for any pinholes in the filler. If you see pinholes, add another coat of filler and sand the surface. Prep rust holes by sanding down to the bare metal and applying fiberglass filler. If the rust hole is too large, welding new metal to the surface is best. The metal prep work will take the longest, but is the most important part of painting your car.
Sand the prep work using long strokes and using increasingly finer sandpaper. Sand on an angle to prevent grooves in the car surface. Use a straight edge to judge the smoothness of the sanding and the curvature of the car. Continue to sand the prep work until the surface is totally smooth. If the rest of your car paint is in good condition, you don't need to sand it. However, if the paint job on your car is flaking or in bad shape, sand the rest of the car surface.
Apply a urethane primer that's considered "high build", sold at automotive specialty stores or online. High build primers don't shrink like other primers and will make your prep work and paint job look much more professional. High build primers also build up more, making it easier to sand and create even surfaces. Sand the primer after its hardened.
Use a sealer before painting the car. A sealer will help the new car paint adhere to the old paint and will keep the paint job looking smooth and uniform. If you're painting the whole car, apply the sealer to the whole car. Sealer can be found at automotive specialty stores or bought online.
Tape off all parts that you don't want to be painted and remove any decals. Tape off the glass, bumpers, door handles, etc. With the metal work done and the car prepped, you are now ready to paint.
