Method of making ceramic molds

Claim 1

IN A METHOD FOR MAKING REFRACTORY CERAMIC CASTING MOLDS FROM A SLURRY OF COMMINUTED REFRACTORY MATERIAL AND A GELLING ALKYL SILICATE BINDER THEREFOR IN WHICH SAID SLURRY IS POURED ON A PATTERN AND GELLED THEREON INTO SEMIRIGID FORM BY HYDROLYSIS REACTION OF SAID BINDER FORMING AN ALCOHOL AS A RESULTANT OF SAID HYDROLYSIS REACTION, THE STEPS WHICH COMPRISE ENVELOPING SAID MOLD AS POURED ON SAID PATTERN AND AFTER AT LEAST PARTIAL GELATION OF SAID BINDER WITH A HARDENING MEDIUM FLUID IN WHICH SAID ALCOHOL IS MISCIBLE, RETAINING SAID MOLD ENVELOPED IN AND SURROUNDED BY SAID HARDENING MEDIUM FLUID FOR A TIME SUFFICIENT TO PRODUCE INTERNAL STABILIZATION AND AGEING OF THE PRODUCT STRUCTURE OF SAID HYDROLYSIS REACTION OF SAID BINDER WITH SAID COMMINUTED REFRACTORY MATERIAL FOR ACHIEVING AN INTERNAL STABILIZATION OF SAID BINDER AND SAID REFRACTORY MATERIAL INTO A STABLE FORM MORE RIGID THAN SAID SEMI-RIGID FORM ACHIEVED ON GELATION OF SAID BINDER, AND HEAT-CURING SAID MOLD TO FINAL RIGID FORM THEREOF WITH REMOVAL FROM SAID MOLD OF SAID HYDROLYSIS REACTION PRODUCT AND SAID HARDENING MEDIUM MATERIALS.