A stack of copper plates is placed in a melting chamber having a closed roof of refractory material. The stack is placed in a tilted orientation leaning against a side wall of the melting chamber, with lower edges of the copper plates resting on an inclined hearth surface. A door to the melting chamber is closed to block the infiltration of oxygen. A burner is fired into the melting chamber to heat the closed roof of refractory material, and the stack of copper plates is melted under the influence of combustion products from the burner and heat radiated from the closed roof. Molten copper is drained downward from the bottom edge of the inclined hearth surface to avoid immersing the copper plates in a molten bath.