Arc Welding is the process by which two pieces of metal are joined together by the use of electrical energy. Arc welding creates an electric arc that melts the base metal and typically a filler wire. The subsequent pool of molten metal then solidifies and fuses the edges of the parent material to join the metal together. To make this possible, electricity is passed from the power source through an electrode. The electric current is converted to heat due to the resistance in the flow of electrons across the air gap. This intense electrical energy creates an arc.