GB919194A - Improvements in or relating to paints for foundry moulds and cores - Google Patents

Abstract

A water paint for application, e.g. by brushing, dipping or spraying, to foundry sand moulds and cores, e.g. of silica or olivine sand, prior to metal casting, e.g. steel casting, comprises a refractory powder and algin or an alginate as a suspending agent together with an organic bonding agent. The refractory powder may be zirconium silicate (zircon), silica, magnesia, magnesite, chromite, alumina, titania, olivine, graphite or fused china clay (molochite). The bonding agent may be dextrin or linseed oil. The suspending agent may be sodium alginate. Clay, as extender, and formaldehyde, sodium benzoate and sodium pentachlorophenate, as preservatives, may be present. The bonding agent, with or without additives, and a strong solution of sodium alginate or algin may be premixed to form a concentrate which may then be mixed with a refractory powder and water as desired; or a refractory powder, bonding agent, with or without additives, sodium alginate or algin and water may be mixed to form a paste to which water may be added as required. In the examples, the specified paints consist of zircon flour, dextrin, sodium alginate and water; and zircon flour, dextrin, linseed oil, bentonite clay, sodium alginate and water.