Abstract
The strength of sand mold bonded with water glass was increased by dehydrating the mold. The sand mold was made by mixing pure silica sand with water glass. The dehydration of the sand mold was accomplished to an extent of 80% under reduced pressure, while it was dehydrated to around 60% in an atmosphere of 51% in humidity. In the latter case, the compression strength of the mold was about 40 kg/cm2 when the amount of water glass added 5%. It was increased with increasing the amount of addition, molar ratio, and specific gravity of water glass to be added to the sand.
