A method of cranial repair and the cranial implant molding device used therein, the device having a frame or base that receives a bottom or convex molding plate and a top or concave molding plate in a manner whereby the two plates are separated a distance to receive a settable or curable implant forming material therebetween. The plates are separated by a compressible member such that by the use of threaded mechanical fasteners or similar members the distance between the two plates can be adjusted by tightening or loosening the mechanical members. The thickness of the implant is varied by varying the separation distance on different sides of the frame.