Wipe clean the surface of your porcelain sink with a paper towel and rubbing alcohol. You can also use soap and water. Never use an abrasive cleaner on porcelain surfaces because it dulls and scratches them.
Dry the surface of your porcelain sink after you have cleaned it. The surface must be free of lint, dust and other debris in order to be repaired.
Fill all the chips, cracks and scratches on your porcelain sink with epoxy. Put the epoxy on a cosmetic wedge and carefully dab it into the affected area. Smooth out the surface with the wedge so the epoxy is only in the scratch, chip or crack.
Allow the epoxy to set for an entire day. This will ensure the epoxy is completely dry before you complete the repair.
Paint the spots that you filled in with the epoxy with a enamel or epoxy paint that matches your porcelain sink. Use a small paintbrush for precision.
Allow the paint to dry for two days before using your sink.