valandite tootmine vahtpolüstüroolist või teistest vahtpolümeeridest valamisel valuvormist mitte-eemaldatavaid gaasistuvaid mudeleid kasutades (vt gaasistus; vrd gaasistuvmudeltäppisvalu), an expendable pattern process in which an expendable polystyrene or expanded polymethylmethacrylate pattern surrounded by the unbonded sand, is vaporized during pouring of the molten metal (see: gasif