This document discusses three main types of arc welding: shielded metal arc welding (SMAW or stick welding), gas metal arc welding (GMAW or MIG), and gas tungsten arc welding (GTAW or TIG). SMAW uses a consumable electrode coated in flux, while GMAW and GTAW use inert shielding gases and non-consumable tungsten electrodes to produce the welding arc.