Method of making high temperature resistant models or tools

A method of producing a model or tool comprising the sequential steps of:

• (a) mixing a first component containing a curable epoxy resin and a thixotropic agent with a second component containing a hardener system comprising at least one polyethyleneimine, at least one other amine having at least two amino hydrogen groups and a complex of a Lewis acid and a Lewis base having latent reactivity in a mix block to form a curable paste wherein the curable paste has a density of between 1.1-1.6 g/cm3;
• (b) machine dispensing the curable paste on an outer surface of a substructure in the form of a continuous layer;
• (c) curing the continuous layer of curable paste at room temperature;
• (d) post-curing the layer of paste at a temperature of at least 50° C.;
• and
• (e) machining the cured continuous layer to produce the model or tool
• wherein the thixotropic agent comprises hydrophilic fumed silica, the Lewis acid is BX3 AlX3, FeX3, FeX2, ZnX2, TiX3 or TiX4 where X independently represents a C1-6 alkyl group, C1-6 alkoxy group, hydrogen, bromine, iodine or fluorine atom provided that when the Lewis acid is BX3 no X represents a fluorine atom, the Lewis base is ammonia or a compound of the formula Z(Ra)3 in which Z is nitrogen or phosphorus and each Ra independently represents a hydrogen atom;
• an alkyl group having from 1 to 20 carbon atoms optionally substituted by one or more phenyl groups in which each phenyl group may be optionally substituted by one or more C1-12 alkyl groups and/or halogen atoms;
• a phenyl group optionally substituted by one or more C1-12 alkyl groups and/or halogen atoms;
• a C5-7 cycloalkyl group;
• or two Ra's together represent an alkylene group having from 4 to 6 carbon atoms one or more of which may be replaced by an oxygen or a sulphur atom and the curable paste after curing has a heat deflection temperature above 100° C.