TIG welding (Gas Tungsten Arc Welding, GTAW) uses a non-consumable tungsten electrode in a hand torch, shielded by argon gas. The welder strikes an arc between the tungsten and the parent metal, then optionally dips a separate filler rod into the weld pool with the other hand. AC TIG handles aluminium; DC TIG handles steel and stainless.
TIG produces the cleanest, prettiest welds in the trade. It's the standard for stainless-steel pool fence panels, exposed architectural welds, and any joint where the weld bead is a visible feature.
Trade-off: TIG is slow. A weld that takes 30 seconds with MIG might take 3 minutes with TIG. For high-volume gate work, TIG is reserved for finishing welds and stainless. Bulk steel fabrication runs on MIG.