Spot welding is a process in which contacting metal surfaces are joined by the heat obtained from resistance to electric current. Items being welded are held together under loads exerted by electrodes. The procedure uses two shaped copper alloy electrodes to concentrate welding current into a tiny "spot" and at the same time clamp the sheets together. Forcing a large current through the spot will melt the metal and form the weld. Spot welding produces a lot of energy which can be delivered to the spot in a very short. This permits the welding to occur without excessive heating to the rest of the sheet.