Tungsten Inert gas (TIG) is one type of arc welding. It is used for complex and stylistic welding on a variety of metals including copper and titanium. TIG welding uses a tungsten electrode to direct the welding arc onto the work piece. TIG welding requires the use of a shielding gas to push air away from the weld. Argon is used as a shielding gas for TIG welding. Because the electrode does not provide filler material like other arc-welding processes, a separate welding rod or wire rod or wire has to be used if filler material is needed to complete the weld. Push method is best for positioning the electrode. Electrode is held at a 10 to 15 degree angle from vertical and pointed towards the direction of the weld. The welder uses the electrode to create a small pool of molten metal and then pushes the metal forward with the electrode in a cyclic motion, adding filler material as needed.