A method of coarse enameling material, such as the surface of conventional rebar, which increases adhesion between the surface and a matrix, such as a cement-based mortar or concrete, in which the material is embedded. In one embodiment, a glass fit is fired onto a surface to achieve an enamel finish, the finish is then cooled and heat softened. A refractory material, such as dry portland cement, is applied to the heat softened enamel, and the resultant coarse coating is then fired and cooled to produce a final hard coarse enameled surface. The reaction of the refractory component in the coarse enameled surface upon insertion in fresh mortar or concrete prevents the formation of soft precipitates at the interface of the cementitious matrix and the coarse-enameled reinforcement. One embodiment involves adding portland cement Type I-II to a softened glass frit as a final coating over an initial base coating that if fired on the steel to prevent corrosion of the underlying steel. The coarse topcoat of enamel produces a strong chemical bond between it and a concrete or mortar matrix and the base coat of enamel eliminates or significantly reduces the potential for corrosion.