← Back to Bead BoardTIG welding amperage chart
TIG gives you the most control of any arc process. You run the heat with a foot pedal, feed filler by hand, and shield with pure argon. It is slower than MIG, but the bead quality is hard to beat on anything from mild steel to aluminum. This chart covers mild steel, stainless, and aluminum with tungsten sizing, filler rod diameter, cup size, and gas flow for every common thickness. All settings assume 100% argon shielding gas.
Quick answer
1/4 inch mild steel TIG: 150–200 amps, DCEN, 1/8" tungsten, 1/8" ER70S-2 filler, #8–#10 cup, 20–25 CFH argon.
TIG mild steel settings
Polarity: DCEN (DC−) · Filler: ER70S-2 · Gas: 100% Argon · Rule of thumb: ~1 amp per 0.001″ of thickness
TIG stainless steel settings
Polarity: DCEN (DC−) · Filler: ER308L / ER316L · Gas: 100% Argon · Rule of thumb: ~0.8 amps per 0.001″ (runs 15–20% cooler than steel)
Stainless is more sensitive to heat than mild steel. Keep your travel speed up and use a gas lens to extend your shielding. Back-purge the root side on anything you care about. Stainless sugars fast.
TIG aluminum settings
Polarity: AC · Filler: ER4043 / ER5356 · Gas: 100% Argon · Rule of thumb: ~1.2 amps per 0.001″ (needs ~20–25% more heat than steel)
Aluminum requires AC polarity. The EN half of the cycle provides penetration, the EP half cleans the oxide layer off the surface. Set your AC balance to 65–75% EN for most work. Use a pure or balled tungsten tip, or a ceriated/lanthanated electrode with a rounded point.
Tungsten electrode sizing chart
Amperage capacity by tungsten diameter. DCEN ranges are for steel and stainless. AC ranges are for aluminum.
Polarity guide
Cup size and gas flow
Questions welders keep asking
What size tungsten for 1/4 inch steel?
1/8" (3.2 mm) tungsten for 1/4 inch mild steel or stainless. That size handles 160–330 amps on DCEN, which covers the 150–200 amp range you need for 1/4 inch. Sharpen it to a point with a 2.5:1 taper length. If you are running over 200 amps consistently, step up to 5/32".
AC or DC for aluminum TIG?
Always AC. Aluminum has an oxide layer that melts at 3,700 degrees F, way above the base metal at 1,220 degrees F. The EP half of the AC cycle blasts through that oxide. Without it, the filler balls up on the surface and never wets in. Set your AC balance to 65–75% EN for the best mix of cleaning and penetration.
How much argon flow for TIG welding?
15–25 CFH covers most shop work. Start at 15 CFH for thin material with a #5 or #6 cup, and go up to 25 CFH for 1/4 inch and thicker with a #8 or #10 cup. If you are getting porosity, check for drafts and leaks before turning up the gas. Too much flow causes turbulence that pulls in atmosphere. A gas lens lets you run lower flow with better coverage.
Lanthanated vs thoriated tungsten — which one?
Lanthanated (gold band, 1.5% or 2% La2O3) for everything. It starts easier, holds a point longer, and works on both AC and DCEN. Thoriated (red band, 2% ThO2) was the standard for decades and works great on DC steel and stainless, but the thorium is mildly radioactive. Grinding dust is the real concern. Ceriated (gray band) is another non-radioactive option that runs almost identically to thoriated on DC. If you only want to stock one type, go lanthanated.
How do I size TIG filler rod?
Match the filler rod diameter to the tungsten diameter as a starting point. For 1/16" tungsten, use 1/16" filler. For 3/32" tungsten, use 3/32" filler. For 1/8" tungsten, use 1/8" filler. You can go one size smaller for more control on thin material, or one size larger for faster fill on thicker joints. The charts above show the recommended filler for each thickness.
What gas do I need for TIG welding?
100% argon for all TIG welding. Steel, stainless, aluminum, it does not matter. Unlike MIG, there is no mixed gas for TIG. Some guys use argon/helium mixes for deeper penetration on thick aluminum, but straight argon is the standard. Buy industrial grade (99.995% pure). If your supplier asks about a mix, they are thinking of MIG.
Why does my tungsten keep contaminating the weld?
Three common causes. First, you are dipping the tungsten into the puddle. Shorten your arc length or pull the torch back. Second, your amperage is too high for the tungsten diameter. Check the sizing chart above and step up a size. Third, you are touching the filler rod to the tungsten. Feed from the leading edge of the puddle, not the arc. If the tungsten is already contaminated (gray or balled tip), break off the end, regrind, and start fresh. A contaminated tungsten puts inclusions in your weld.
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Electrode amperage, polarity, and rod selection by application.
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