Abstract: In a casting mold making system for blowing and packing casting sand accommodated in a receiver of a blow head into a cavity in molding dies by feeding pressurized gas into the receiver, the pressure of pressurized gas to be fed into the receiver is discontinuously raised at least once in the course of feeding of pressurized gas into the receiver.

Abstract: In blowing gas-curing casting sand, which is accommodated in a receiver of a blow head, into a cavity in molding dies and thereby packing it into the cavity, prior to the blowing and packing of the casting sand into the cavity, the casting sand in the receiver is stirred by a stirrer until the stirring resistance of the stirrer enters a predetermined range (a range corresponding to an optimum bulk density range of casting sand within which casting sand can efficiently blow out through blow nozzles).

Abstract: A casting mold which is molded by heating mulled sand including a mixture of refractory molding sand particles, an inorganic water soluble binder and water, wherein the inorganic water soluble binder is made of a combination of a sulfate compound such as magnesium sulfate heptahydrate and a borate compound such as sodium tetraborate decahydrate. The casting mold is formed by baking the mulled sand in such a manner that at least part of the sulfate compound retains water of crystallization therein and the borate compound is once fused and then cured.

Abstract: A casting mold which is molded by heating mulled sand including a mixture of refractory molding sand particles, an inorganic water soluble binder and water, wherein the inorganic water soluble binder is made of a combination of a sulfate compound such as magnesium sulfate heptahydrate and a borate compound such as sodium tetraborate decahydrate. The casting mold is formed by baking the mulled sand in such a manner that at least part of the sulfate compound retains water of crystallization therein and the borate compound is once fused and then cured.

Abstract: In a water-soluble casting mold according to the present invention, after casting sand is obtained by adding a water-soluble binder containing an inorganic sulfate compound such as magnesium sulfate or the like easily solved in water and water to a refractory granular material for casting sand, the casting sand is dried by microwave radiation or the like in such a manner that the inorganic sulfate compound in the binder is kept retaining at least a portion of crystal water and accordingly, since the inorganic sulfate compound exists in hydrate state in the mold, the mold after drying is provided with good water-solubility and a sufficiently high strength as well, thereby it is possible to recover easily and use repeatedly the binder.