The quality of the final product depends on the quality of castings, their accuracy and cost–effectiveness. Given the operating conditions of the casting mold, it must have certain mechanical, chemical and technological properties that ensure the production of high–quality castings. The development and application of cold–hardening mixtures for casting molds while preserving the indicators of their basic physical, mechanical and technological properties, and the development of their preparation technology are urgent tasks for foundry production. The aim of the research is to improve the quality of the casting mold by improving the physical and mechanical properties of molding mixtures using the Alpha–set process. The parameters such as compressive strength, tensile strength, bending strength, crumbleness and vitality were studied, which were determined by standard methods. The article presents the results of research and optimization of technological and physical and mechanical properties of mixtures. The regularities of the interaction of the resin with the hardener and quartz sand were established. Based on the planned experiment, mathematical models of the properties of mixtures on quartz sand with phenol–formaldehyde resin were developed. The compositions of cold – hardening resin mixtures on quartz sands were optimized, which allows obtaining high–quality forms with high strength properties. Industrial studies have shown that the optimal composition of the mixture is the amount of resin from 0.8 to 2.0%, the amount of hardener - from 0.4 to 1.0%.