A cast iron foundry shop is not a suitable environment for working because of dust and noise produced mainly by molding and shake-out machines. To seek a solution to these problems, a study was carried out to investigate molds using a water-soluble binder to make separation of silica sand from cast iron products easy in water. The silica sand mold with under 10percent barium chloride, under 1percent carbohydrate and a small amount of water, gave satisfactory results as a water-soluble mold. The compression strength of this mold rose to about 50kg/cm2 and it collapsed promptly in water by the easy dissolution of the binder after dipping, Drying by microwave was most usefull for hardening this mold. When the water-soluble mold containing castings were dipped in water, silica sand separated immediately from castings. The water-soluble mold did not have a harmfull influence on the defect and quality of castings.
