Alkyd oil, unbaked

This process is mostly used for single castings or for small batch production in steel foundries. It provides the benefit of a good surface finish and good stripping properties. However, it is 

An oil modified polyester resin is mixed with isocyanate, producing a polyurethane resin, which hardens slowly. The curing of the mould is accelerated by a catalyst and completed by heating to 150 T. 

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