GB698202A - Improved sand cores and moulds - Google Patents

Abstract

698,202. Flasks; core bars; mould and core materials. SHEEHAN, J. J., and CONEYGRE FOUNDRY, Ltd. March 7, 1952 [March 8, 1951; July 25,1951], Nos. 5653/51 and 17622/51. Class 83 (i). Sand moulds and cores are reinforced by introducing organic fibrous material impregnated with a solution of an intermediate condensation product and then hardening this into an insoluble resin, or the hardening may be effected before its introduction. The fibrous material may comprise string or rope of jute, &c., or a textile sheet of natural or artificial fibre which may be folded or rolled and the condensation product a solution in water of metholurea or a soluble phenolaldehyde condensation product. A hardening accelerator, e.g. boric acid, may be added. The impregnation may be effected by dipping and the material may be first wetted with the solvent. The flexible material may be threaded into a mould or core after attaching it to a piece of wire which acts as a needle. Hardening of the resin occurs in this case during stoving of the mould, &c., and some of the solution may percolate into the sand itself before it hardens. Whether the hardening is effected before or after inserting in the mould, a textile-covered wire, e.g. of steel, may be used in place of mere fibrous material.