TIG is an acronym for Tungsten Inert Gas, an arc welding process that uses a non-consumable electrode (tungsten), under the protection of inert gas. The welding can take place with or without a filler metal. This technique offers several advantages, including the quickness of its execution, adaptability to any working position, the ease with which the arc can be controlled and thus the regularity of deposits, the regulation of the current within a wide range, and powerful, concentrated heat sources. Thanks to this last characteristic, very thin materials can be welded (as thin as .5mm) in a short amount of time.
This type of welding was initially developed for the aeronautic industry during World War II to replace rivets on aircraft with welding, which weighed less while boasting the same strength. TIG welding has limits to its application due to the impossibility of using elevated currents. TIG cannot be used in continuous currents and direct polarization since the electrons arriving at the anode (the piece being welded) cannot break the oxide.