Tungsten inert gas (TIG) welding is a type of arc welding that uses a TIG welder to melt TIG welding rods with an electrode’s electric arc, to form a weld pool. A TIG welding rod is essentially filler metal for the weld, and is typically made of a low alloy steel. Welding rods may vary by container size, number per box, number of rods per containment tube, rod diameter, rod length and tensile strength (in PSI), among other considerations.