Like MIG welding, flux-cored wire requires three main components: arc, filler metal and a protective gas. Just like MIG welding, core welding works by feeding the electrodes continuously into the joint. First, the welder squeezes the trigger, and then the wire feeder begins to feed the electrodes into the joint while the electrodes are charged. Once the electrode strikes the metal joint, the electricity is shorted and the electrode is heated until the electrode begins to melt. Once the electrodes begin to melt, the metal begins to melt and then they all begin to form a puddle. The molten pool simultaneously melts the flux core to form shielding air while generating slag to protect the weld from contamination.