Furan foundry binder system containing a curing promoter

A treated core sand material capable of being formed into a predetermined shape and bound by an acid curable resin at a temperature of at least about 250.degree. F. so as to retain a shape for use in metal founding, said treated core sand material containing core sand, a furan based binder, a metal sulfonate curing catalyst for said binder and a cure promoter selected from copper chloride, zinc chloride and iron chloride.

A method of preparing a core sand material adapted for the production of sand shapes at a temperature of at least about 250.degree. F. which comprises treating a core sand with a furan based binder, a metal sulfonate curing catalyst for said binder and a cure promoter selected from copper chloride, zinc chloride and iron chloride.

A method of controlling the curing properties of a furan based binder used in the manufacture of sand shapes, said method including adding to the sand used to form said sand shapes a metal sulfonate curing catalyst and a curing promoter selected from copper chloride, zinc chloride and iron chloride, mixing with the treated sand a furan binder and then curing said binder at a temperature of at least about 250.degree. F.