Shell mold structures and processes and compositions for forming the same

Claim 1

AN INVESTMENT COMPOSITION IN THE FORM OF A SLURRY FOR APPLICATION AS A LAYER OR FILM TO A FROZEN MERCURY PATTERN BELOW THE FREEZING TEMPERATURE OF THE PATTERN MATERIAL AND PRODUCING A SHELL-LIKE MOLD AROUND SAID PATTERN, SAID COMPOSITION COMPRISING AS NORMALLY SOLID COMPOSITION INGREDIENTS WHICH FORM THE APPLIED FILM A REFRACTORY MATERIAL OF SMALL PARTICLE SIZE CONSTITUTING A PREDOMINANT AMOUNT OF SAID SOLID INGREDIENTS, AN INORGANIC RAISED TEMPERATURE BINDER FORTHE REFRACTORY PARTICLES CONSTITUTING FROM 0.25% TO 5% OF SAID SOLID INGREDIENTS AND SELECTED FROM THE GROUP OF SUBSTANCES CONSISTING OF ALUMINUM PHOSPHATES, ALKALI METAL PHOSPHATES, ALKALI METAL FLUORIDES, MIXTURES OF ALKALI METAL FLUORIDES AND BORIC ACID, MIXTURES OF ALKALI METAL FLUORIDES AND BORIC OXIDE, ALKALI METAL BORATES, BERYLLIUM BORATES, ALKALI METAL SILICATES, AND MIXTURES OF AT LEAST TWO OF SAID SUBSTANCES, SAID INORGANIC BINDER BEING PRESENT IN AMOUNT SUFFICIENT TO BIND THE REFRACTORY PARTICLES OF A SHELL-LIKE MOLD INTO A SELF-SUPPORTING STRUCTURE AFTER HAVING BEEN RENDERED EFFECTIVE AS A BINDER AT A RAISED TEMPERATURE BETWEEN 150* C. AND 1250* C. TO WHICH A MOLD IS SUB-