Abstract: A resin composition for investment casting contains a moderate boiling temperature liquid inert diluent, having a boiling point in the range of about 200.degree. to 300.degree. C. The presence of the liquid inert diluent allows the resin to be used as a pattern, or model, in investment casting by preventing breaking of the mold during burnout of the resin. Any of the conventional resins suitable for stereolithography may be employed in the practice of the invention. To the resin is added a moderate boiling point solvent in the amount of about 5 to 30 wt %. Use of the moderate boiling point solvent in conjunction with the resin allows the pattern to shrink and crack at moderate temperature before final burnout. The shrinkage occurs faster and at a lower temperature as compared to the prior art.