What Is TIG Welding? How GTAW Works
TIG welding is the common name for Gas Tungsten Arc Welding (GTAW). It uses a non-consumable tungsten electrode to create the arc. Unlike stick and MIG, the electrode does not melt into the weld. Instead, the welder feeds a separate filler rod by hand into the puddle. Pure argon shields the weld pool. TIG produces the highest quality welds of any arc welding process, with no spatter and no slag. When a weld needs to be perfect, TIG is the process.
How TIG Welding Works
The tungsten electrode sits in a ceramic cup (nozzle) at the end of the TIG torch. When you start the arc, the tungsten gets hot enough to emit electrons but does not melt into the weld. It just creates and maintains the arc.
The welder holds the torch in one hand and dips filler rod into the puddle with the other hand. A foot pedal or fingertip control on the torch lets the welder vary amperage in real time, giving precise heat control that no other process matches.
Pure argon flows from the torch cup and blankets the weld pool. The result is a clean, controlled weld with no spatter, no slag, and no smoke. What you see in the puddle is exactly what the finished weld looks like.
Equipment You Need
TIG requires the most equipment of any arc process: a constant current power source (AC/DC if you want to weld aluminum), a TIG torch with ceramic cup, tungsten electrodes (2% lanthanated is the all-purpose choice that works on AC and DC), filler rods matched to your base metal, an argon gas bottle and regulator, a foot pedal or fingertip amperage control, and a ground clamp.
This is the most expensive welding setup. A quality TIG machine with AC/DC capability costs significantly more than an equivalent stick or MIG unit. But if you need to weld aluminum or produce code-quality stainless welds, the investment is unavoidable.
Filler Rod Selection
TIG filler rods are matched to the base metal. Using the wrong filler can cause cracking, corrosion failure, or rejected welds.
ER70S-2 for mild steel and carbon steel. Triple-deoxidized for the cleanest welds.
ER308L for 304 stainless steel. The L means low carbon, which prevents carbide precipitation and maintains corrosion resistance.
ER316L for 316 stainless steel. Contains molybdenum to match the base metal's chloride corrosion resistance.
ER4043 for general aluminum work. Contains 5% silicon for good fluidity and crack resistance. The default choice when you are unsure.
ER5356 for structural aluminum and marine applications. Contains 5% magnesium for higher strength and better anodizing response.
Advantages of TIG Welding
Highest weld quality and appearance. TIG welds are the gold standard. The stacked-dime pattern on a good TIG bead is unmistakable.
No spatter, no slag. The finished weld needs no cleanup beyond a wipe with acetone.
Precise heat control. The foot pedal lets you vary amperage in real time, which means you can control exactly how hot the puddle gets at every point in the weld. This is critical for thin material and heat-sensitive alloys.
Welds virtually any metal. Steel, stainless, aluminum, titanium, copper, nickel alloys, magnesium, even gold and silver. If it is a metal, TIG can probably weld it.
Excellent on thin material. TIG can weld material as thin as 0.020 inches with the right settings and technique.
Best for visible welds. When the customer will see the weld or appearance is part of the specification, TIG is the only process that consistently delivers.
Limitations
Slowest arc welding process. Filler is fed by hand one dab at a time. Deposition rates are a fraction of MIG or even stick. TIG is not practical for filling large joints or production volume.
Most difficult to learn. Both hands are occupied (torch and filler rod), one foot works the pedal, and your eyes track the puddle. It takes months of dedicated practice to develop the coordination for consistent results.
Expensive equipment. An AC/DC TIG machine with a good torch, foot pedal, and gas setup costs substantially more than MIG or stick.
Requires perfectly clean material. Any contamination, oil, oxidation, or fingerprints show up immediately as porosity or discoloration. Surface prep is not optional with TIG.
Extremely wind-sensitive. Even a slight draft disrupts the argon shield. TIG is an indoor-only process in practice.
Low deposition rate. Impractical for thick structural work where you need to fill large V-grooves or make heavy multi-pass welds.
When to Use TIG Welding
TIG is the right process for food-grade stainless fabrication, aerospace components, aluminum welding, thin-wall tubing, and any weld that will be visible and must look perfect. When the spec says "GTAW only" or the weld will be X-rayed, TIG is what you use.
It is also the default for exotic metals like titanium, Inconel, and copper alloys where contamination control is critical.
TIG is the wrong choice when speed matters more than appearance, when you are welding outdoors, or when the joint is thick enough that filling it by hand would take all day. For those jobs, use MIG or stick and save TIG for where it actually matters.
Reference data only. Verify all settings against manufacturer documentation and the applicable welding code before use. Amperage ranges are starting points that vary by position, fit-up, and material. Welding involves serious injury risks including burns, electric shock, fume exposure, and fire. This site does not replace proper training, certification, or employer safety procedures. See full terms of use.
Classification system defined by AWS A5.12, AWS A5.18, general welding process knowledge.