ABSTRACTA study was made of the reactions occurring in adherence when firing ground coats containing no adherence‐promoting oxides. Enamel coatings were fired on trial pieces of steel through three stages or zones and the results of each firing were noted. It was found that in laboratory tests, enamels which do not contain cobalt and nickel oxides have good adhering qualities if they are correctly fired. Iron oxide increases the refractive index of the ename