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TIG welding is easiest to control when the distance between the tungsten and the workpiece stays nearly constant. That distance is the arc length. If it changes while you weld, the arc voltage, heat pattern, bead width and shielding coverage change with it. A consistent arc length does not require a perfect hand; it requires the right setup, a stable body position and a method for moving the torch.
Choose the Right Arc Length
For most TIG work, keep the arc length close to the tungsten diameter. With a 1/16-inch tungsten, start at about 1/16 inch between the tungsten tip and the workpiece. With a 3/32-inch tungsten, a gap of 3/32 to 1/8 inch is usually workable. Thin sheet metal may need a slightly shorter arc, while a joint with limited access may force a longer one.
| Situation | Typical arc length | What happens if it is too long |
|---|---|---|
| Thin steel or stainless sheet | About 1/16 inch | Wider, less concentrated heat and more distortion |
| General steel or aluminum work | About 1/16 to 1/8 inch | Less penetration and a less focused arc |
| Large joint or awkward access | Up to about 1/8 inch | More arc wandering and greater gas exposure risk |
The arc length is measured from the end of the tungsten to the surface of the puddle or parent metal, not from the ceramic cup. A long stick-out can make that distance look shorter than it is. If the arc suddenly sounds harsh or the puddle becomes broad and pale, bring the tungsten closer before changing amperage.
Set Up for Control
Clean metal makes arc control easier. Remove oil, paint, oxide, scale and marker residue from the weld area. On aluminum, use a dedicated stainless-steel brush immediately before welding. Contamination creates an unstable puddle that can make a correct arc length seem incorrect.
Set the tungsten stick-out according to the cup and joint. About 1/8 inch beyond the cup is a useful starting point for an exposed joint. Recess the tungsten slightly for a tight corner, and extend it farther only when the cup can still provide adequate coverage. A gas lens can support more stick-out than a standard collet body, but it does not make an excessively long arc acceptable.
Use the smallest practical cup that still covers the puddle. A large cup can improve shielding in a draft, but it may obstruct your view and encourage you to hold the torch too far away. A TIG gas lens kit is a sensible upgrade when you regularly weld stainless, tubing or joints that require extra tungsten extension. It is less necessary for occasional mild-steel repairs.
Build a Stable Hand Position
Rest the side of your torch hand, wrist or forearm on a clean part of the workbench whenever possible. Use your other hand to support the filler rod or to brace against the table. The goal is to move from the elbow and shoulder while keeping the torch hand from bobbing up and down.
Before striking the arc, rehearse the travel path with the torch switched off. Check that your helmet, gloves and forearms will not catch on the table. Arrange the work so the torch lead does not pull against your hand. Even a small tug can lift the tungsten at the end of a pass.
Keep the torch roughly 10 to 20 degrees from vertical in the direction of travel. Excessive angle directs the arc across the joint rather than into it and makes the effective arc length inconsistent. Move the torch slowly enough that your eyes can follow the leading edge of the puddle, but not so slowly that heat builds uncontrollably.
Use the Puddle as Your Gauge
Do not judge distance only by the position of the ceramic cup. Watch the arc and puddle. A short, tight arc has a concentrated bright core and a relatively narrow puddle. As you lift the torch, the arc becomes longer and often noisier, while the puddle spreads and loses penetration.
Practice making straight beads without filler on clean scrap. Concentrate on keeping the puddle width uniform. If the bead widens and narrows in rhythm with your hand movement, your arc height is changing. A simple drill is to scribe parallel lines 1/4 inch apart and follow one line while maintaining the same puddle width.
For filler welding, dip the rod at the front edge of the puddle without moving the torch vertically. Feed small additions—often every one to two seconds—and pause travel briefly during each dip. If the tungsten touches the filler, stop and inspect it. A contaminated tungsten can make the arc wander and may require grinding before continuing.
Match Settings to Arc Control
Amperage does not fix a poor arc length. Set current for the material and joint first, then correct torch position. As a broad starting point, thin steel may need roughly 1 amp per 0.001 inch of thickness, although joint fit-up, copper backing and travel speed change the result. Aluminum commonly needs more heat because it conducts heat quickly.
Use a foot pedal or torch control if you are learning or welding joints with changing mass. It lets you reduce current as the workpiece heats, without lifting the torch to control the puddle. A TIG welding foot pedal costs more than a fixed-current setup, but it is often more useful than buying a higher-amperage machine.
Set shielding gas high enough for coverage but not so high that turbulence pulls air into the weld. Around 15 to 20 cubic feet per hour is a common starting range with argon and a standard cup. Increase it only for drafts, larger cups or unusual access. A draft shield may solve a problem that extra gas cannot.
Troubleshoot Arc-Length Problems
If the weld is wide, shallow and gray, first shorten the arc and check gas coverage before increasing current. If the arc wanders, inspect the tungsten point, collet fit, work clamp and torch lead. If the tungsten repeatedly balls or melts, verify polarity, current range and tungsten type rather than simply holding it farther away.
When the joint requires a long arc, accept the trade-off: penetration and control will suffer. Reduce travel speed only if the material can tolerate the extra heat, and use a gas lens or larger cup for shielding. For repeat work, make a small fixture or add a temporary rest so your torch hand has a physical reference.
A TIG torch rest can help with long bench welds, but it is not a substitute for a comfortable work position. If you weld only occasional repairs, a clean block of steel or a homemade rest may work just as well. The consistent result comes from supporting the torch, keeping the cup visible and maintaining a short, deliberate arc.