Abstract: The method of contemporaneously sealing interfaces of bearing surfaces for valve faces and cylinder linings in a steel rotary cylindrical barrel having a plurality of longitudinal bores extending through the barrel longitudinally from one end to the other, each of the bores having a restricted diameter intermediate portion connecting a valve surface area at one end of the barrel with a cylinder area extending to the other end. An insert of bearing material is placed in both ends of the bore and a cap secured over a lower end adjoining the cylinder bore. A removable carbon hot top is placed over the other end of the barrel. The barrel and its assembly is heated in a metallurgical furnace for 90 minutes at 1925.degree. F.