Patent ID: 7994235

Claim:
A method of making a seamless model comprising the steps of: a) providing at least one tank filled with a resin component and another tank filled with a hardener component; b) delivering the resin component and hardener component from the tanks to a mix block and mixing the resin component and hardener component to produce a modelling paste wherein the modelling paste is a low density thixotropic curable paste comprising a resin composition and microballoons; c) dispensing the modelling paste onto an outer surface of a support in a continuous layer; d) curing the paste at room temperature; and e) machining the cured paste to a desired or pre-determined contour to form the seamless model wherein the microballoons are present in an amount of greater than about 50% and less than about 80% of the uncured paste by volume and wherein the density of the uncured paste is in the range of about 0.4 g/cm 3 to about 0.9 g/cm 3 and wherein the resin composition is a polyurethane composition comprising: (i) an organic polyisocyanate component; (ii) a polyol component comprising greater than about 50% by weight of a high molecular weight polyol and less than about 50% by weight of a low molecular weight amine-based polyol; and (iii) a chemical thixotropic agent.