MIG welding settings chart: voltage, wire speed and gas flow
On a MIG welder you set voltage (volts), wire feed speed (inches per minute, IPM) and gas flow (cubic feet per hour, CFH). You pick wire size by the thickness of the metal. The chart below is your starting point. The final tuning is done by ear and by the shape of the bead.
.030 in (0.8 mm) wire: metal .020–.080 in (0.5–2.0 mm), 15–19 V, 160–275 IPM, 17–21 CFH. .035 in (0.9 mm) wire: metal 1/16–3/16 in (1.6–4.8 mm), 18–24 V, 160–355 IPM, 21–25 CFH. Mild steel, flat position, solid ER70S-6 wire. Starting point only: confirm with your machine manual.
MIG settings chart by wire size
| Wire | Metal thickness | Wire feed speed | Voltage | Gas flow |
|---|---|---|---|---|
| .030 in (0.8 mm) | .020–.080 in (0.5–2.0 mm) | 160–275 IPM (4–7 m/min) | 15–19 V | 17–21 CFH (8–10 L/min) |
| .035 in (0.9 mm) | 1/16–3/16 in (1.6–4.8 mm) | 160–355 IPM (4–9 m/min) | 18–24 V | 21–25 CFH (10–12 L/min) |
| .045 in (1.2 mm) | 5/32–5/8 in (4–16 mm) | 200–470 IPM (5–12 m/min) | 20–30 V | 25–32 CFH (12–15 L/min) |
| 1/16 in (1.6 mm) | 3/8 in (9.5 mm) and up | 160–315 IPM (4–8 m/min) | 25–35 V | 30–38 CFH (14–18 L/min) |
Table 4.2 of the e-book The Welder's Forge: mild steel, flat position, solid ER70S-6 wire. Starting point: confirm with the wire package, the WPS or the machine manual. For auto body panels (22 to 20 gauge), use .023 in (0.6 mm) wire, or .030 in at most.
What each setting does
- Wire feed speed sets amperage. Faster wire means more current, more penetration and more metal deposited. On a MIG machine the wire speed is what pulls the amperage.
- Voltage sets arc length. More voltage gives a longer arc and a wider, flatter bead. Less voltage gives a narrow, tall bead.
- Gas flow protects the puddle. Too little lets air in and you get pinholes. Too much creates turbulence and also pulls air in. More is not better.
How to dial it in, step by step
- Pick the wire by metal thickness (chart above) and check that the drive rolls and contact tip match the wire size.
- Set voltage in the middle of the range for your wire.
- Adjust wire feed speed on a scrap of the same metal until the arc sounds steady, like bacon frying, with no popping.
- Fine-tune voltage by the look of the bead (signs below), one change at a time.
- Set the gas to the chart flow and make sure no fan or open door is blowing across the gun.
If this is your first time powering the machine up, the spool, gas and polarity come first: see how to set up a MIG welder.
Signs of voltage too high (or wire too slow)
- A long, hissing arc with a wider sound.
- A ball forming on the wire tip before it drops.
- A wide, flat bead with more spatter. On thin sheet it burns through easily.
Signs of voltage too low (or wire too fast)
- The wire stubs into the work and pushes the gun back.
- An unstable arc with irregular popping.
- A narrow, tall, rope-like bead sitting on top of the metal.
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Check the work clamp. It should be on clean, bare metal close to the joint. A poor ground makes an arc that spits and looks like a bad setting.
Why the chart changes with thickness
At low voltage (15–22 V) MIG runs in short-circuit transfer: the wire touches the puddle many times per second with little heat. It is the mode for thin metal and for welding out of position. At high voltage (27–35 V) with an argon-rich gas it moves to spray transfer: a quiet arc, almost no spatter and a lot of deposition, but only in the flat position on thicker plate. That is why .045 and 1/16 in wire show much higher voltages (Table 4.1 of the e-book).
What if my machine does not show volts?
Many 120 V machines have only voltage taps (A, B, C…) and a wire speed dial from 1 to 10. Use the chart as a proportion, and check the chart printed inside the wire compartment door: low voltage and slow wire for thin metal, then raise both together as the metal gets thicker. Write down the settings that worked for each thickness. For body panels, spacing and heat control are covered in welding thin sheet metal without burning through.
What about the gas?
For mild steel the usual choice is C25, 75% argon and 25% CO₂. Pure CO₂ is cheaper but spatters more. The differences are in MIG welding gas compared. If your machine has no gas connection at all, these numbers do not apply: read gasless MIG with flux-core wire.
Frequently asked questions
What voltage should I use for .030 wire?
What gas flow should I use for MIG welding?
Why does my wire keep stubbing into the plate?
Does this chart work for flux-cored wire?
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