Patent ID: 6901989
Filing Date: 2005-06-07
Classification: B22C,B22D,F02F

Abstract:
1. In the process for the lost foam casting of aluminum comprising the principle step of forming a pattern from a polymeric foam, depositing a refractory coating on the surface of said pattern, embedding said pattern in a bed of sand that forms a mold about said pattern, pouring molten aluminum into said mold to vaporize and displace said pattern, replicate said pattern with said aluminum and coat said aluminum with said coating, allowing said aluminum to solidify into a casting, and removing said sand from said casting, the improvement comprising said coating comprising a sufficient amount of a thermally stable, water insoluble, acid-gasifiable compound to rupture said coating upon gasification, and wetting said coating with an acid to dissociate and gasify said compound and rupture said coating.