Give your car a thorough look and locate all the rust spots. Begin by loosening up the rust from these spots with the help of sandpaper or sanding disk in a drill. Make sure you do not use any of the rust spots untouched. Continue to sand until bare metal is exposed.
Mix a small amount of fibreglass paste according to manufacturer’s instructions. Use this paste to fill holes that may have formed on the car’s body as a result of rust accumulation. Allow enough time for the paste to dry completely. Sand the hardened paste to get rid of excess paste.
Mix an appropriate amount of body filler according to the instructions of the manufacturer. Apply a uniform layer of body filler on all the repaired areas of the car. Allow time for the body filler to dry completely and then sand the filler smooth. Consider using solvent wipes at this point to ensure complete removal of dust particles.
Apply a uniform layer of primer from a primer spray bottle on the areas being repaired. Allow time for the primer coat to dry after which you will have to wet –sand the repaired area and wait once again until it dries. You may have to spray more than one primer coat.
Once the final coat of primer from the previous step dries completely, apply a thin layer of topcoat. Allow it to dry and see if another layer is required. Generally, you may have to apply at least three layers of top coat. Just make sure that you allow time for the first layer to completely dry before applying the next one.
Finally, polish the repaired areas. Make use of polishing compound for this purpose. Apply some wax to restore shine on repaired parts of the car.