How to Form a Concrete Sink

Choose a sink mold style. Integral, vessel and pedestal are the three types of sink molds available. Build the sink mold yourself using melamine-coated particle board or purchase a mold from a supplier. Purchasing a pre-made sink form is easier and the best option if you are a novice. Pre-made sink molds are also designed to be used multiple times.

Mix the concrete. The Portland Cement Association recommends using Type II concrete because it is the least likely to not crack. Mix the concrete carefully, following the bag's directions. Properly mixed concrete has a texture similar to oatmeal. Add coloring pigments, such as stains, dyes or tints.

Pour the concrete in the form and smooth with a trowel and allow the concrete to cure the time recommended on the bag. This can take up to three days.

Remove the sink from the mold and apply a sealer made specifically for concrete. Like paint, sealers are available in a variety of finishes, such as flat, matte or glossy.