Patent ID: 7958932

Claim:
A method of forming a foam pattern for casting comprising: heating a polyol component to a predetermined temperature; heating an isocyanate component to a predetermined temperature; mixing said polyol component and said isocyanate component to form a liquid mixture; adding a reaction agent to said mixture that accelerates the reaction of said polyol component and said isocyanate component; adding a skin forming agent to said mixture; coating a mold cavity of a mold with a heat activated release agent; pouring said mixture into said mold cavity of said mold without direct injection by a reaction injection molding machine, such that a reaction from the mixture of said polyol component and said isocyanate component form a foam pattern structure having: a shape that corresponds to the inside surface configuration of said mold cavity; a structure comprising an aggregate pattern density of not more than 8 pounds per cubic foot; and an outer surface that is free of porosity; removing said foam pattern from said mold cavity; and applying a coating over at least a portion of said foam pattern surface after removing said foam pattern from said molding to ensure the coated surface is sealed and water tight.