This is a sheet metal welder for almost any metal. It does not require the input of material and practically does not admit it unless they are very thin rods. It is not about electric arc welding. What melts the metal is the graphite tip that shortly turns bright white. What is heated by the current is graphite, not metal, Graphite electrode because the first one has a much greater resistance and dissipates most of the power. It is important that the graphite tip is sharp for two reasons http://www.shj-carbon.com/graphite-products/graphite-electrode/