Rusted cars look old and beaten-down, and most people don't take the time to repair them correctly. Most paint jobs on rusted cars don't last long because the original rust isn't completely removed. Rust has to be removed before painting over it or it will continue to spread even underneath the new paint. Sand a rusted car to remove the rust and create a solid base for new paint.
Instructions
1. Sand the surface of the car with 80-grit sandpaper and a dual-action sander. Keep the surface of the sander flat against the car.
2. Move the sander back and forth along the car's surface until all the rust is gone and you see the bare metal.
3. Replace the 80-grit sandpaper with 180-grit paper. Sand the car again using the dual-action sander. The 80-grit sandpaper slightly gouges the metal and the 180-grit will smooth the surface.
4. Change the paper again and use 320-grit sandpaper on the dual-action sander to smooth the surface further and prepare it for primer.
5. Use masking tape and paper to cover parts of the car that don't need primer. Cover the glass, lights, door handles, tires, wheels, trim and keyholes.
6. Spray self-etching primer on the car's bare metal surface. Self-etching primer adheres to bare metal and protects it from moisture, which can cause new rust to form within 24 hours. Hold the sprayer 12 inches from the surface and spray left and right, not up and down. Let the primer dry for 10 minutes.
7. Spray a second coat of self-etching primer onto the car's surface and let it dry for one hour. The car can be painted or it can be left alone with only the primer to protect it for several weeks.
