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TIG welding amperage chart, tungsten size and AC balance for steel, stainless and aluminum

TIG on 1/8" steel: 112 – 138 A, DCEN, 3/32" tungsten. The same 1/8" in an aluminum fillet jumps to 124 – 151 A on AC, same 3/32" tungsten, about 70% EN balance — the joint shape alone moves the number. WeldMaster's TIG calculator (Pro) works out amperage, tungsten, cup, filler rod and argon flow from the material, joint and thickness.

3 min read · Updated 2026-09-15

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What is the rule behind the TIG amperage chart?

TIG starts from the same rule as MIG: about one amp per thousandth of an inch. WeldMaster then adjusts it for the material and the joint:

  • Steel: thickness in inches × 1000.
  • Stainless: × 0.66, because it holds heat and distorts easily.
  • Aluminum over 1/4": × 1.25, to make up for the heat it pulls away on AC.
  • Fillet joints: × 1.10 over a butt joint.
  • The amperage window is that center ±10%.

What is the TIG welding amperage chart with tungsten and cup size?

WeldMaster TIG results (tungsten is 2% lanthanated in every row)
Material, joint, thicknessAmperageCurrentTungstenCupFiller rod
Stainless, butt, 1/16"37 – 45 ADCEN1/16"#5–#61/16" – 3/32"
Steel, butt, 16 ga54 – 66 ADCEN1/16"#5–#61/16" – 3/32"
Stainless, butt, 1/8"74 – 91 ADCEN1/16"#5–#63/32" – 1/8"
Steel, butt, 1/8"112 – 138 ADCEN3/32"#6–#73/32" – 1/8"
Aluminum, butt, 1/8"112 – 138 AAC3/32"#6–#73/32" – 1/8"
Aluminum, fillet, 1/8"124 – 151 AAC3/32"#6–#73/32" – 1/8"
Steel, fillet, 1/4"248 – 302 ADCEN1/8"#7–#81/8" – 5/32"

Argon flow is 15.0 – 20.0 CFH in every row, or 7.1 – 9.4 L/min in Metric.

What size tungsten does TIG welding need?

The tungsten follows the center amperage. Below 100 A the app suggests 1/16", from 100 A to under 220 A 3/32", and from 220 A up 1/8". The cup follows the tungsten: #5–#6 (5/16"–3/8") for 1/16", #6–#7 (3/8"–7/16") for 3/32" and #7–#8 (7/16"–1/2") for 1/8".

So what size tungsten for 1/8 steel? 3/32", because the center is 125 A. For 1/8" aluminum the answer is also 3/32", in a butt or a fillet joint. For 1/8" stainless it drops to 1/16", because the center is only 82.5 A.

What are TIG welding aluminum settings for AC balance and frequency?

Aluminum runs on AC. The electrode-positive half of the cycle breaks up the oxide skin, and the electrode-negative half puts heat into the work. For aluminum, WeldMaster adds two rows: AC Balance at about 70% EN (electrode negative) and AC Frequency at 100–120 Hz.

If your machine has no balance or frequency control, skip those two rows; the amperage, tungsten and filler still apply. The app has no settings for pulse or for other tungsten types.

How do you get TIG settings in WeldMaster?

  1. Open TIG from Calculators (Pro).
  2. Under Material, pick Steel, Stainless or Aluminum.
  3. Under Joint, pick Butt or Fillet.
  4. Set Joint Thickness, from 0.012" to 1/2".
  5. Read Amperage, Current, Tungsten, Cup Size, Filler Rod and Gas Flow; for aluminum also AC Balance and AC Frequency.
  6. For the filler alloy (ER70S-2, ER308L, ER4043...), open the Filler Selector under Reference.

What are common TIG mistakes?

  • Setting the machine's maximum a little above the top of the range, then riding the pedal or torch control down into it, avoids guessing a fixed number.
  • Stainless needs noticeably less current than steel of the same thickness: 74 – 91 A against 112 – 138 A at 1/8".
  • Thick aluminum climbs fast: over 1/4" the app multiplies by 1.25 and warns that preheat and a larger cup help fusion.
  • A tungsten that balls or spits is usually too small for the current; move up one size.

Questions and answers

What tungsten does WeldMaster suggest?
Always 2% lanthanated (blue), in 1/16", 3/32" or 1/8" depending on the current. It does not cover other tungsten types.
What are TIG settings for 1/8" stainless?
For a butt joint, WeldMaster gives 74 – 91 A on DCEN, a 1/16" tungsten, a #5–#6 cup, 3/32" – 1/8" filler rod and 15.0 – 20.0 CFH of argon.
Does the TIG calculator cover pulse?
No. It gives amperage, current type, tungsten, cup, filler rod and gas, plus AC balance and frequency for aluminum. There are no pulse settings.
How thick can I go?
The Joint Thickness goes up to 1/2". Thick aluminum gives very high amperages, so check them against what your machine can deliver.

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