I hear people talk about TIG welding, but My uncle was a "heliarc welder". Whats the difference?

The "TIG" in TIG welding stands for Tungsten Inert Gas. But Before it was called TIG" it was given the name "Heliarc" because helium was the gas that was used when the process was invented. But then someone discovered that argon worked better and so it was called TIG because inert gas could refer to either helium or argon. But wait, then someone else discovered that small additions of hydrogen worked well for some metals. The word "Inert" no longer held true so the eggheads decided a new name was required. So nowadays, the technical term for what used to be called TIG and Heliarc is Gas Tungsten Arc Welding or "GTAW". But Guess what? people still call it TIG and even Heliarc. In fact more people call it TIG welding than Gas Tungsten Arc Welding.

Exactly What is TIG?

TIG welding is akin to gas welding as far as welding technique in that the torch is held in one hand and the filler rod is manipulated with the other hand. It is considered more difficult than other arc welding processes because it requires the use of both hands. Often times a foot pedal amperage control is also used which adds another layer of difficulty.

A TIG torch can be either water cooled or air cooled and is designed to provide shielding gas as well as welding current through a tungsten electrode. A ceramic nozzle directs the shielding gas to the weld puddle and internal copper parts like the collet and collet body hold the electrode in place. The tungsten electrode is sharpened for applications where the arc needs to be pinpointed and for very low amperage. The heat the melts the metal and makes the weld puddle comes from the arc that is created between the tungsten electrode and the workpiece. The arc is shielded by argon, helium, or a mixture of the two. Sometimes for certain alloys, hydrogen is added in small percentages to improve the way the puddle flows. The arc is very smooth and quiet and clean when DC current is used. When the TIG welding machine is set on Alternating current, it is slightly more noisy but still clean and smooth.

What Metals can be welded using the TIG process?

Almost any metal can be welded with TIG. Carbon and low alloys steels like 1010 carbon steel and 4130 chromoly steel,Stainless steels like 304, 321, and 17-7ph, Nickel alloys like inconel 718 and Hastelloy X, Aluminum alloys like 6061,5052, Magnesium alloys like az31b, Titanium alloys like commercially pure, and 6al4v, Cobalt alloys like Stellite 6b and l605, copper alloys like Nibral bronze and pure copper, All can be welding using the TIG welding process.