An apparatus for forming a bathtub liner over an existing bathtub comprising a container, a seal, a heating element, and a pressure increasing element. The container defines a cavity. The seal is associated with cavity and is capable of forming a substantially continuous seal with a bathtub liner. The heating element is capable of heating the cavity, and in turn, the liner. The pressure increasing element is capable of increasing the pressure within the cavity, to in turn, force a bathtub liner outwardly, away from the cavity. Upon positioning of the liner and apparatus over an existing bathtub the pressure increasing element will force the liner toward and into contact with the surfaces of the existing bathtub.