Electroforming uses electrolysis to make a metal copy of an object. A model or mandrel is made of the object to be copied, usually in wax. The mandrel is made conductive by coating it with graphite or conductive paint. It is then placed in a tank containing the electrolyte and connected to the negative output from the rectifier (cathode). An electrode of the metal to be used for deposition is attached the positive output (anode). As the current flows through the system a layer of metal is deposited on the mandrel. When the metal layer is thick enough to be self-supporting it can be removed from the tank. A wax mandrel can be removed from the cast by making a small hole in it and applying heat to melt the wax.