These markings will transfer to the plaster model when the mold is poured to aid in model modification. The rest of the limb is wrapped with rolls of plaster gauze and the prosthetist contours the plaster mold by pushing it gently into the load bearing areas. The cast is carefully removed and identified with a name and number. At this point the cast is referred to as a negative model or mold, since it is used to create a positive model. Modification Powder or soapy solution, used as a separator, is liberally applied to prepare the mold for filling.
Plaster is then mixed and poured into the mold, which is held in sand or a holding fixture.
A metal pipe in placed in the plaster so that the model is easily held. Once the plaster hardens, the cast is stripped away and a positive model of the limb is left with the ink markings from the cast. He begins by checking his measurements and remarking the anatomic landmarks. Plaster is removed from the model with a rasp in areas that are load tolerant while bony and sensitive areas are left untouched. Since soft tissue compresses within the socket, more plaster is removed if the residual limb is relatively fleshy to insure a tight fit.