A sizing composition for the foundry industry, comprising particulate amorphous silica and acid

It is a sizing composition as described for use in the foundry, in particular comprising particulate amorphous silica (SiO Next is described the use of a sizing composition according to the invention for producing a coating on a water glass-bonded foundry molding, and a method of producing a sized with an aqueous sizing water glass bonded foundry molding (mold or core). Also specifies a kit, including containing a sizing composition of the invention.