The vinegar and baking soda mixture should cause the rust particles to loosen. If your bumper still shows signs of rust, repeat the process over again. Wipe down the bumper with water or soap once you’ve removed the rust to be sure to have a nice clean surface. [3] X Research source
If you need to remove flaking spots, deep scars, or do heavy sanding, you should use 40- to 60-grit paper. For fixing small imperfections, try 80- to 120-grit paper. For a very smooth surface, use 360- to 600-grit paper. This should leave you with a surface without many scratches.
Grease and wax remover can be purchased at a home improvement store, auto shop, or online.
When spraying in between layers, self-etching primer should only take a couple of minutes to dry. Allow the last coat to sit for 3-4 hours before starting to sand.
Depending on which type of primer you’re using and what kind of paint you’ll be using on top, the regular primer’s drying time will vary. Check the instructions on the primer to see how long to let it sit.
If you do happen to sand through the primer and reach the chrome surface, re-apply the primer, let it dry, and sand again.
You can use water, lacquer thinner, or a wax and grease remover to wipe away the dust.
If you do have drips, you can use 2000-grit wet sandpaper to gently sand down the paint run.
For correct drying times, check your paint’s directions to see how long to wait between coats.
