If you'd like to alter the color of your bathroom sink or hide scars and discoloration, apply a new surface coat. Whether your bathroom sink is metal, porcelain, or another waterproof material, it is poorly-suited for a new surface coat. Prepare it, using techniques appropriate to its composition, or the new surface coating will eventually flake free and circle the drain.
Wash your bathroom sink to prevent adhesion difficulties. A trisodium phosphate cleanser will provide best results. Don't use a soft sponge; this may leave soap scum. Scrub the sink with steel wool and rinse it with wet rags.
Rinse the bathroom sink with clean rags. Be thorough, as any cleanser residue will prevent adhesion. Dry the sink, using towels.
Sand non-metallic bathroom sinks or the primer will not stick. Stop once the sink feels rough to your palms.
Protect the countertop/hardware from paint overspray by using masking paper and tape.
Spray nonmetal sinks with an acrylic primer; spray metal sinks with etching primer. Maintain 8 inches between the bathroom sink and spray nozzle or sagging is likely. Don't apply any paint for two hours.
Spray the sink with epoxy paint. Maintain 8 inches between the bathroom sink and spray nozzle, or sagging is likely. Let the new epoxy surface dry for at least three hours.
Ordinary acrylic and latex paint won't last very long on a bathroom sink. Choose a durable epoxy or expect finish failure.