Welding Arc Welding Shielding in arc welding
 Shielding gas protects the weld by being a pocket of gas around the weld. The purpose of this gas is to keep normal air out, especially oxygen. It is different from flux because there is no liquid on the weld. There is only a gas around the weld. Because there is no liquid, it will not clean up dirt and other things on the metal. This means that the metal has to be clean before it is welded.