in transfer molding thermosetting polymeric materials , a first preform of first thermosetting polymeric material having a volume substantially equal to the volume of the die cavities is placed in the transfer chamber adjacent the runners . a second preform of second thermosetting polymeric material cheaper than the first polymeric material is placed in the transfer chamber above the first preform . the transfer chamber is pressurized and the second preform is deformed and pressurizes and deforms the first preform and causes the first thermosetting polymeric material to flow through the runners into the die cavities . after curing , the molded articles consisting of first thermosetting polymeric material are removed from the die cavity , and scrap cull and runner consisting substantially of cheap second thermosetting polymeric material are removed from the mold runners and the bottom of the transfer chamber . thus , considerable economies are effected . the material of the second preform is selected for certain physical properties . various means are shown for loading the transfer chamber .