Spot welding is a welding process that is primarily used on thin metal sheet without adding any materials. This welding process falls under the larger category of electrical resistance welding. A weld is made on the spot by having a powerful electric current pass through a small area on the workpiece, which makes the metal melt at that spot. This is typically used for ordinary or stainless steel, but can also be used for aluminium or galvanised steel. The layers of sheet material to be welded are forcibly clamped between two electrodes. These electrodes are used to send a brief (on the order of 10 ms) but very powerful (up to 100kA) electrical current through the workpiece. This current generates a lot of heat at the place where the electrical resistance is the highest. Assuming the connection cables are thick enough, this will be the place where the metal parts pressed together meet.