If you're tired of looking at rust stains and yellow mineral deposits every time you brush your teeth, freshen up your sink with a coat of white paint. It's less expensive than replacing the sink, and an afternoon of effort can create a vessel that more closely matches your fresh new decor. The key to good results, whether your sink is porcelain, acrylic or enameled cast iron, is proper cleaning and etching to ensure the epoxy or urethane topcoat adheres.
An essential procedure before beginning your project -- and one that's easy to forget -- is to turn off the water valves under the sink. For best results, it's a good idea to remove the stopper and drain, but you can carefully cover these with painter's tape if you prefer. It's also a good idea to remove the faucet; it tends to get in the way, even if you aren't painting the deck in which it rests.
Cleaning and Etching
Clean the sink with a strong detergent such as 1/2 cup of trisodium phosphate mixed with a gallon of water to remove all grease, soap and oil that could prevent paint from sticking. Scrub thoroughly with an abrasive sponge; then rinse. It's best to do this part before you disassemble the drain.
Fill any nicks and gouges with auto body filler. Mix the filler with hardener; trowel it on with a plastic putty knife and scrape it flat. Sand it flat with 36- or 50-grit sandpaper; then use 80- or 100-grit paper to smooth out the scratches. Fill the scratches in the putty with fiberglass glazing compound, and sand it with 120- or 150-grit sandpaper.
Wipe on a bonding agent if you plan to coat porcelain or acrylic enamel with epoxy or acrylic urethane enamel. The bonding agent, which ensures paint adhesion on these glass-like surfaces, isn't necessary if you're painting an acrylic sink. Instead, scuff the sink with 220-grit sandpaper or scour it with 000 steel wool.
You get the best results by applying the paint with a sprayer, but it's OK to use a brush, especially if you're using a product made specifically for brushing on sinks, bathtubs and bathroom tile. Keep the room ventilated well while painting; if you're spraying, wear a respirator.
Apply a coat of paint to the sink that is thick enough to level out to a smooth finish but not thick enough to drip. Don't worry if you don't get full coverage with the first coat -- it's better to apply several thin coats than it is to apply a single coat that drips or separates.
Let the first coat dry for about 15 minutes if spraying and about an hour if brushing; then apply a second coat. Repeat once more.
Let the final coat dry overnight; then create the design you want to add, using stencils and spray urethane or an artist's brush. Let the design dry overnight.
Apply one or two coats of protective clear urethane finish. This is optional if you painted the sink a solid color, but it isn't optional if you added a design. The design will chip off without it.