Gas tungsten arc welding (GTAW), also known as tungsten inert gas (TIG) welding, is an arc welding process that uses a non consumable tungsten electrode to produce the weld. Gas tungsten arc welding is most commonly used to weld thin sections of stainless steel and light metals such as aluminum, magnesium, and copper alloys among other metal properties except for lead and zinc. The process grants the operator greater control over the weld than competing procedures such as shielded metal arc welding and gas metal arc welding, allowing for stronger, higher quality welds.

The electric arc was discovered and developed by Humphry Davy in 1800. C.L Coffin also had the idea of welding an inert gas atmosphere in 1890, but even in the early 1900, welding non-ferrous materials like aluminum and magnesium remained difficult. To solve the problem, bottled inert gasses were used in the beginning of 1930. The electric arc process was perfected in 1941, and became known as heliarc or tungsten inert gas welding because it utilized a tungsten electrode and helium as a shielding gas. In 1953, a new process based on GTAW was developed, called plasma arc welding. It affords greater control and improves weld quality by using a nozzle to focus the electric arc, but is largely limited to automated systems, whereas GTAW remains primarily a manual, hand-held method.

Advantages:
1- Concentrated Arc
2- No Slag
3- No Sparks & No Spatter
4- Little To No Smoke Or Fumes
5- Welds More Metals And Metal Alloys Than Any Other Process
6- Good For Welding Thin Materials

Disadvantages:
1- Slower travel speeds than other processes
2- Lower filler metal deposition rates
3- Hand-eye coordination is a required skill
4- Brighter UV rays than other processes
5- Equipment costs can be higher than other processes
6- Concentrations of shielding gas may build up and displace oxygen when welding in confined areas

Books to read for more information on TIG, ARC, and MIG welding:

- Welder's Handbook: A guide to plasma cutting, ArC, MiG and TiG welding by Richard Finch

- The Essential Welder: Gas Tungsten Metal Arc Welding by Larry Jeffus

- A Practical Guide to TIG Welding by P.W. Muncaster

- Modern Welding by Carl H. Turnquist, William A. Bowditch, Kevin E. Bowditch and Mark A. Bowditch

- Gas Tungsten Arc Welding Handbook by William H. Minnick

- Performance Welding Handbook (Motor books Workshop) by Richard Finch

Websites to visit for more information on the TIG welder as well as other welders; Instructables, Carmen Electrode, Lincoln Electric and Miller Welds.