Even though the paint used on rubber bumpers is flexible, it will still crack and flake after most impacts, even minor ones. The sun also plays havoc on rubber bumper paint, bleaching it and making it look old and neglected. When it's time for you to spruce up your rubber bumpers with a new paint job, follow these simple steps for professional-looking results.
Remove all lights and bumper stickers from your bumper.
Apply a degreaser and wax remover to your bumper following manufacturer's instructions. Use a scouring pad to clean as thoroughly as possible. Wipe down with a damp rag when finished.
Spray on a household cleanser such as Fantastic or Formula 409. Scrub the entire bumper very thoroughly with a scouring pad, removing all dirt and grime and as much of the old paint as possible. Wash it off well with plenty of clean water and then dry with a cloth.
Sand the bumper with 80-grit paper until all old paint has been removed. This can take some time and elbow grease. Wash the bumper to remove all dust and grit when the sanding is completed. Wipe with a clean lint-free cloth.
Mix enough flexible bumper repair material (following the manufacturer's instructions) to cover the entire bumper using an auto body filler spreader. Make certain the repair material is smooth and that it fills in any holes or gouges or scratches in the bumper. Work quickly as the repair material can only be worked for about five minutes and sets up within approximately 15 minutes.
Sand the repair compound once it has completely dried (give it an hour just to be sure). Sand lightly with 180-grit paper and a sanding block, just until the surface feels smooth. If imperfections are still present, spread on a second thin layer of flexible bumper repair material, allow it to dry and sand again until smooth.
Wet sand the entire bumper once it is smooth with 220-grit paper and a sanding block. sand lightly, just until the surface feels smooth and slick. Rinse with water and dry with a lint-free towel. Mask the bumper from the rest of the car with masking tape (paper or plastic can be taped to the body of the car to prevent any over spray of paint from getting on the body of the car).
Spray on a medium coat of the flexible bumper paint and allow it to flash-off--that is, dry until it is a dull colour--before spraying on a second medium coat of paint. Allow the paint to dry for 45 minutes.
Wet sand the paint with 320-grit sandpaper and a sanding block until the paint feel as smooth as glass. wash and dry with a lint-free cloth.
Spray two more coats of paint onto the bumper, allowing the paint to dry between coats. Allow the second coat to dry thoroughly and wet sand with 400-grit paper and a sanding block. Wash clean when the bumper feels completely smooth and dry with a lint-free cloth.
Spray one final coat of paint and allow the final coat to dry overnight. Remove the masking tape and the job is complete.