Sink - Materials. 1  Sinks are made of many different materials. 2  Enamel over steel or cast iron. 3  Polyester. 4  Resin washbasin. 5  Soapstone. 6  Stainless steel. 7  Stainless steel is commonly used in kitchens and commercial applications because it represents a good trade-off between cost, usability, durability, and ease of cleaning.