This work presents the results of a study of the mechanism of occurrence of such a defect in artistic and engineering casting as non-metallic inclusions. The contact angles of the popular imported model composition for art and jewelry casting with different types of binders used for LVM were studied, namely GS-20 and the now popular aqueous binder «Armosil». The process of spreading a suspension over a substrate of a jewelry model composition was studied using a high-speed camera using two different methods. The resulting patterns were presented in the form of graphs. At the end of the article, a method for minimizing the appearance of non-metallic inclusions in art and engineering castings is given.