Sometimes it is simpler to join two sheets of metal in spot welds instead of full welds that may damage the pieces. A spot weld is the fusing of two pieces of metal by applying pressure at a contact point and passing an arc between the two contact points. Automobile manufacturers use spot welds to join body panels. There is little material waste and if done right, the weld is almost invisible once polished. A good alternative for pieces of metal that do not need the structural rigidity of a full weld.