A device (2) for making a seamless, anatomically contoured, prosthetic device for supporting or maintaining the position of mammalian tissue, organ or structure or a replacement thereof, such as a breast implant, includes a support plate (8), an ironing plate (12) or a clamping plate and a core plate (16), each of which is made from a thermally conductive material. The support plate and the ironing or clamping plates have openings formed through the thickness thereof. The core plate has a core extending (20) outwardly from a lower surface thereof which is received through the openings in the ironing or clamping plate and the support plate.