The most common materials used to make bathtubs are porcelain, acrylic, fiberglass, enameled cast iron and cast polymer, according to About.com. Each material creates a different look, weight and feel for the tub.
Porcelain tubs are easy to find and inexpensive, but the surface can chip easily. Acrylic and fiberglass bathtubs are more durable than porcelain and are also reasonably priced, explains About.com. Enamel cast iron tubs are strong and last a long time but are difficult to install and are very heavy. Cast polymer tubs are affordable and come in many color options, but they can crack if the gel coating wears off.