Investment molding using refractory material and certain organic bases

Claim 1

A PROCESS FOR PRODUCING MOLDS WHICH COMPRISES MIXING REFRACTORY GRAINS WITH A SOLUTION OF AN ESSENTIALLY NONVOLATILE, CHEMICALLY BASIC, ORGANIC GELLING AGENT IN A VOLATILE ORGANIC SOLVENT, SAID ORGANIC GELLING AGENT BEING CHARACTERIZED BY ITS AIR STABILITY AT AMBIENT TEMPERATURE AND BEING SOLID AT TEMPERATURES OF FROM 70-160* F., EVAPORATING SAID VOLATILE SOLVENT FROM THE REFRACTORY GRAINS TO PRODUCE REFRACTORY GRAINS HAVING A THIN COATING OF SAID ORGANIC GELLING AGENT SUBSTANTIALLY COVERING THE INDIVIDUAL GRAINS, MIXING SAID COATED GRAINS WITH A SOLUTION OF A BINDER IN A SOLVENT THEREFOR TO FORM A SLURRY AND THEN IMMEDIATELY POURING THE RESULTING SLURRY IN A MASTER MOLD, SAID SLURRY BEING A PREHYDROLYZED ALKYL SILICATE SOLUTION IN A SOLVENT THEREFORE, ALLOWING SAID SLURRY TO GEL, AND THEN REMOVING THE GELLED MOLD FROM THE MASTER.