A handmade pottery sink can be a beautiful addition to a bathroom, but it is not a project for beginners. This how to article is for people who already have some throwing skill, and also have an access to pottery kiln.
Decide what kind and what dimensions of sink you want to make. Calculate your clay shrinkage and write down the wet diameter.
Weigh the needed amount of clay. Remember that sinks should be much thicker then most of the pots you have ever made. You probably will need about 6-9 kg (13.2-19.8 lb) of clay for a 30 cm (12 in) external diameter sink or 12-15kg (26.4-33 lb) for 42 cm (16 7/8 in) diameter sink. The quantity of clay depends on the sink type. Vessel sinks need to be thicker than drop-down sinks.