TIG Arc Length

Forget about all the things you have heard about difficulties with TIG welding. One of the single most important things that can be done to reduce the difficulty of TIG is to control the arc length. The arc length is the distance between the tungsten and the base metal, that the arc travels between. Arc stability is one of the difficulties encountered in TIG welding both steel, stainless and aluminum.

It is arc length that is largely responsible for the stability of the arc itself, if gas flow and torch angle is correct. Too long of an arc will increase the possible paths the arc can take to the metal or the tungsten (depending upon DC or AC selection). It will also create a broad arc, that can reduce the ability to control the heat, and overly reduce penetration. Too short of course, you run the danger of “dipping” the tungsten. When this occurs, it takes time to stop and regrind the tungsten because of the contamination that results also can destabilize the arc.

So, it leads to the question, “What is the recommended arc length?” Although it can vary depending upon the joint design, and the individual technique, a good starting point is about a credit card’s thickness off the metal. It takes practice to hold that kind of arc length. Proper positioning, and getting comfortable helps, but nothing will substitute for muscle memory. Of course adjusting the tungsten to the proper stickout, any where from 1/8” to -1/4” will also help by improving visibility and allowing the tungsten to be stuck down into the “V” of the weld far enough to be close to the bottom of the joint so the arc won’t wander to the side of the joint.

Arc length of course, isn’t the only thing that controls arc stability, as I alluded to earlier, particularly in AC, but it can help keep the arc very close to where you aim it.