A study of iron and bronze technology based on metallographic analysis of artifacts from the Upemba Depression, Zaire, is presented. Metal artifacts have been made there for around 1,500 years. Iron objects are characteristically made by forging and pressure welding techniques, and worn-out tools were typically recycled by reworking into a new object. There is evidence for similar techniques having been used for copper and copper alloys, and it is shown experimentally how the difficulties associated with such an approach could have been overcome. It is not clear whether copper or iron was the first to be produced. The social and cultural implications of these findings are discussed.