Tape this above the welder. Then still run a test bead.

TIG on mild steel is about 1 amp per 0.001 inch. 1/8" starts near 125 A. Aluminum wants ~1.5× because it dumps heat. None of this replaces scrap.

Stick: rod diameter ≈ half the base-metal thickness, then use the amperage window for that rod. MIG: 0.023" under 3/32", 0.030" through 3/16", 0.035" above. Duty cycle scales with the square of the amperage ratio — that's why turning the machine up cooks it faster than you think.

Use it in 10 minutes. Measure thickness. Pick process. Set the window. Burn scrap until the bead looks like the last one that held.

Thickness → power class (mild steel)

Steel thickness	TIG amps	Stick rod	Machine class
1/16" (62 mils)	50–75	1/16" E6011 @ 35–60	120 V hobby
1/8" (125 mils)	100–150	1/8" E6011 @ 75–125	120 V ok, 240 V comfortable
3/16" (188 mils)	150–225	5/32" E6011 @ 110–165	240 V
1/4" (250 mils)	200–300	1/8" @ 90–140, multi-pass	240 V, 180–220 A
3/8"+ (375+)	300+	Multi-pass, preheat	Shop machine

Amp windows from published Lincoln / Miller / ESAB charts, same as welding-calculator.com. Rod-diameter rule: never smaller than 1/16".

1/4" steel is the line between a 140 A hobby MIG and a real shop machine. If that's your job, don't buy the 120 V unit because the box said 'welds 1/4 inch' in tiny asterisks.

Need the quote forms and follow-up texts so the shop actually gets paid? That's the Welding Shop Operating Pack on shoppacks.net — $49.

Comment keyword: AMPS — that's the word we ask for on X/LinkedIn. We DM this page.

Run the welding calculator → Print / Save PDF