Ceramic sinks were built to be durable. However,such a sink may crack due to a heavy object falling into it, or by scolding hot water that causes it to expand. No matter the reason for the damage, you can easily repair the cracks with an epoxy adhesive in no time at all. Gather your materials and get to work.
Wash the sink before making the repair to remove grease and other buildup. Soap up the sponge with dish soap and hot water. Scrub the sink and then rinse it out. Dry it completely with a towel.
Fill the crack with the epoxy adhesive. Use the toothpick to spread it into the crack more easily. Allow 24 hours for the epoxy to dry.
Apply a thin coating of appliance paint over the repaired area. Use the paintbrush, and try to use as few brush strokes as possible to minimize the visibility of the repair. Allow several hours for the paint to dry.
Spray on a list mist of acrylic aerosol sealant to seal the repair. Wait 24 hours before using the sink.