Things You'll Need
Liquid dish soap
Fiberglass filler kit
1200-grit wet sandpaper
Fiberglass is a common material for sinks, because it is relatively cheap and easy to maintain. Over time, however, the sink can get scratched and nicked. Scratches attract dirt, which can be difficult to clean. Repair nicks and scratches with a fiberglass filler kit and a gelcoat kit. Purchase these at a hardware or home improvement store.
Add a few drops of liquid dish soap to a few cups of warm water. Mix until you see soap suds form.
Dip a clean cloth into the solution and rub it over the sink to remove the soap scum or hard water stains on the sink.
Rinse the sink with clear water and let it dry completely.
Spread fiberglass filler into the cracks or nicks on the fiberglass sink. Smooth out the filler with the plastic scraper.
Let the hardener dry completely for several hours.
Sand the entire sink with 80-grit sandpaper. Repeat the process with 180-grit and 360-grit sandpaper. This will smooth out the fiberglass sink and remove small scratches.
Brush off the dust with a soft-bristled brush.
Mix the gelcoat according to the manufacturer's instructions. This will normally involve mixing a hardener with acetone.
Pour the gelcoat into a spray gun tank.
Spray the entire fiberglass sink with one light coat of gelcoat. Don't depress the trigger while keeping the spray gun into one area. This will apply too much gelcoat and will make it drip.
Let the gelcoat dry completely.
Apply acetone to the sink with a clean cloth. This will remove the tacky quality of the gelcoat.
Wet the entire sink with clear water.
Sand the sink with 1200-grit ultrafine wet sandpaper to smooth it out.
Rinse off the sanding dust and let it dry completely.