travel, 2:contact tube, 3:electrode, 4:shielding gas, 5:molten weld metal, 6:solidified weld metal, 7:work-piece Stub-weld repair   Inlay-weld repair   Welding is a fabrication or sculptural process that joins materials, usually metals or thermoplastics , by causing coalescence . This is often done by melting the work pieces and adding a filler