The spent catalysts of petrochemical synthesis, such as: Al2O3, NiO, Mo2O3, CoO, Fe2O3, ZnO, CuO, SiO2, etc., together with alkali metals oxides and boric acid were used to produce the ground enamels with optimum combination of wettability and water resistance, as well as given values of temperature coefficient of linear expansion and impact strength. The dependence of wettability and water resistance on the enamel composition is described using simplex-lattice plane {4, 2}. The regularities obtained make it possible to establish the optimum enamel composition. The best water resistance is observed for the composition with maximum content of (SiO2, Al2O3) catalyst.