Gas Tungsten Arc Welding process used to repair cracks NASA-KSC FACT SHEET Posted: August 9, 2002 The welding process that will be used to repair flow liner cracks found in the orbiter fleet is a Gas Tungsten Arc Welding technique that results in a very pure weld with minimal impurities in the final product. This type of technique is typically used for the welding of oxygen sensitive materials. In the case of the orbiter flow liner cracks, the weld is a full penetration weld that will need to go completely through the metal even though the welder will only...