Load-deflection data, obtained by loading an arm attached to a flat enameled sample, indicate (1) that the load supported, before exceeding the yield point, is greatly increased by the enamel applied on the compression side, although deflection at the yield point is not changed; (2) that enamel applied on the tension side produces a slight increase of load supported before exceeding the yield point, and a definite decrease in deflection with thick coatings as compared to thin coatings or uncoated iron; and (3) that the load and deflection changes with enamel on both sides of the iron are as predicted by combining results in (1) and (2) above. By this information, it is seen that porcelain enamel will produce a definite stiffening effect. There is very little increase in resistance to pure tensile stress when iron is coated with enamel. Strength is greatly increased with enamel under compression. Enamels normally in greatest compression (low expansion enamels) produce the greatest stiffening effect.