Arc welding is a process that joins materials such as metals or thermoplastics by using a welding power supply to create an electric arc between an electrode and the base material to melt the metals at the welding point. The heat from the electric arc melts the metals which when cooled result in a strong joint. There are different types of arc welding including shielded metal arc welding, gas tungsten arc welding and gas metal arc welding which use various filler metals or gases to protect the weld area.