 Gas tungsten arc welding ( GTAW ) , or tungsten inert gas ( TIG ) welding , is a manual welding process that uses a nonconsumable tungsten electrode , an inert or semi @-@ inert gas mixture , and a separate filler material . Especially useful for welding thin materials , this method is characterized by a stable arc and high quality welds , but it requires significant operator skill and can only be accomplished at relatively low speeds . 
