Method for making curable casting resins

A method for making a low-viscosity liquid suspension, adaptable to use as a casting resin and curable in the presence of an agent generating free radicals, said suspension containing a high content of finely divided inorganic filler but being free of any polymeric functional dispersing agent, which method comprises mixing a liquid polymer precursor, an organosilicon compound as an adhesion promotor, and an alkylamine as a catalyst for the organosilicon compound, incorporating finely divided inorganic fillers into the resulting mixture in such an amount that the viscosity of the resulting thixotropic suspension (as determined by means of a rotating cylinder viscosimeter in conformity with DIN 53019, Part 1, at 20.degree. C.) does not exceed 10 Pa.sec, and then converting said thixotropic suspension into a completely deflocculated low-viscosity suspension by letting it stand at room temperature for a sufficient length of time or by heating it for a short time, said liquid polymer precursor consisting essentially of a monomer or monomer mixture or of a mixture of a prepolymer, free of functional groups, dissolved or dispersed in a monomer or monomer mixture.