Granite sinks are extremely durable, often lasting upwards of 10 years. They can, however, be damaged if they aren't treated properly. Keep your sink clean by washing it regularly and drying excess water from the sink's surface when it is not in use. Sometimes it's necessary to make small repairs to your granite sink, such as when you drop a dish into it and a small chip breaks off. These repairs are relatively simple and should only put the sink out of commission for an afternoon.
Scrub the chipped or cracked area of the granite sink thoroughly with a nylon scrub brush and granite cleaner to remove all traces of dirt, algae and other debris. If the damaged area is near the edge of the sink, scrape any existing epoxy away from the seam with a razor knife. Allow the sink to dry completely before continuing.
Add epoxy resin colour, which is available from home supply stores, to part of your epoxy resin, stirring it thoroughly with a putty knife to distribute the colours. Try to make the colour of the epoxy match the colour of your sink as closely as possible. Add the rest of the epoxy to the coloured portion and mix it with the putty knife.
Scrape a small amount of coloured epoxy up with a razor blade and smear it across the crack or chip, holding the razor at a 45 degree angle. Avoid leaving excess epoxy on the surface of the sink. Working quickly, smear more epoxy across the damaged area until it is filled and level with the surrounding surface of the sink. You have only a few minutes before the epoxy begins to harden.
Remove any excess epoxy from the surface of the granite sink with a new razor blade. Gently sand over the damaged area of the sink with fine grit sandpaper to smooth the surface of the epoxy. Allow the sink to remain undisturbed for four to six hours until the epoxy cures completely.