A molding composition for making casting patterns is described containing(a) 10-99.89, preferably 20-90%, by weight of at least one di or polyfunctional acrylic acid and/or methacrylic acid ester which burns without residue,(b) 0.01-5% by weight of an initiator system which can initiate the radical polymerization and(c) 0-80, preferably 10-70%, by weight of organic fillers, pigments and other auxiliary substances burning without residue,the quantity particulars each being related to the total amount of (a)+(b)+(c), characterized in that it further contains(d) 0.1-30, preferably 1-20%, by weight with respect to the component (a) of a chemically inert organic compound burning without residue and having a boiling point and/or sublimation point in the range >150.degree. C.This molding composition is distinguished by not causing any faults in the casting jacket, in particular no crack formation, on burning out of the mold.