MIG welding wire speed and voltage chart
This MIG settings chart is the workhorse reference for fab shops. MIG wire speed, amperage, voltage, and gas flow for mild steel, stainless steel, and aluminum across the common thicknesses, in short-circuit and spray transfer. The numbers come from Lincoln’s published GMAW procedures. Dial them in on scrap before you run production.
Quick answer
1/4 inch mild steel MIG, short circuit: 155–170 A, 19–22 V, .035" wire at 245–290 IPM, C25 at 30–35 CFH, multi-pass. For a one-pass fillet, .045" spray with 90/10 at 260–300 A.
How to read this chart
Find your metal, then the row for your thickness. On a MIG machine you set wire speed and voltage. The amps column is what the machine draws at that wire speed with that wire size, so use it as a check, not a knob. Where a thickness shows up in both the short-circuit and spray tables, like 1/4" steel, short-circuit works in any position and spray is for flat and horizontal only.
MIG mild steel settings (ER70S-6)
Short-circuit transfer
Spray transfer
Short-circuit with C25 covers sheet through 3/16 inch in one or two passes. On 1/4 inch, .035 short-circuit is at the top of its range: bevel the joint, run more than one pass, and cut and etch a test piece to see that it fused. Short-circuit MIG is not prequalified under AWS D1.1, so structural code work needs a qualified procedure. From 1/4" up, the chart switches to .045" spray with 90/10 gas.
For vertical-up and overhead, start with the settings for one thickness thinner. That means less wire speed (and so fewer amps) and about a volt less than flat.
MIG stainless steel settings (ER308L)
Short-circuit transfer
Spray transfer
Short-circuit with tri-mix is the standard for thin gauge and out-of-position stainless. Switch to spray with 98/2 Ar/O₂ on 3/16" and up when you can weld flat or horizontal. Keep your travel speed up. Stainless holds heat and will warp on you.
MIG aluminum settings (ER4043 / ER5356)
Aluminum MIG runs spray (or pulsed spray) only. Short-circuit does not fuse it. Use a spool gun or push-pull setup so the soft wire does not bird-nest. Pure argon, push angle only, never drag. Wire speeds are for 4043. 5356 feeds faster at the same amps, and runs toward the high side of the amp range with the voltage at the low side. On heavy plate a preheat helps, but keep it under about 250 °F so you do not soften 6061.
Spray transfer threshold amps
These are the low ends of Lincoln’s published transition ranges. Below them the arc runs short-circuit or globular. At or above them, with the right gas, the wire sprays: a steady stream of fine droplets and almost no spatter. Spray needs at least 82% argon (Lincoln puts the limit at 18% CO₂). Past that, the CO₂ breaking down in the arc shoves the droplet around and you get globular transfer, not spray. C25 has too much CO₂ to spray, so run 90/10 or 95/5 Ar/CO₂ on steel and 98/2 Ar/O₂ on stainless.
C25 vs straight CO₂
C25 (75% argon / 25% CO₂) is the standard mix for short-circuit MIG on mild steel. It gives you a stable arc, minimal spatter, and a good-looking bead. Straight CO₂ is cheaper per bottle and gives deeper penetration, but the arc is harsher, spatter goes up, and the bead profile is more convex. CO₂ also runs about 2 volts higher than C25 at the same wire speed.
Use C25 for anything visible or where cleanup time matters. Use straight CO₂ when you are welding heavy plate, need the extra penetration, and do not care about grinding spatter. Most shops run C25 for everything and keep a CO₂ bottle around for heavy structural work.
Neither one sprays. For spray on steel, use 90/10 or 95/5 Ar/CO₂. For stainless spray, use 98/2 Ar/O₂. For aluminum, pure argon only.
Short-circuit vs spray transfer
Short-circuit transfer is what most shop welders run day-to-day. The wire touches the puddle, shorts out, and the arc reignites, 20 to 200 times a second. It runs at lower heat, works in all positions, and handles thin material without blowing through. The tradeoff is less metal per hour, more spatter than spray, and a real risk of cold lap on thick plate.
Spray transfer is a continuous stream of fine droplets crossing the arc. Higher amps, higher voltage, more metal per hour, almost no spatter. The downside is a lot more heat and a fluid puddle, so axial spray is flat and horizontal only, on any metal. Pulsed spray (GMAW-P) is the all-position version, and it needs a pulse-capable machine.
Rule of thumb: under 3/16 inch or out of position, run short-circuit. On 1/4 inch and up, flat or horizontal, spray lays down more metal faster with better fusion.
Questions welders keep asking
What wire speed should I set for 1/4 inch steel MIG?
With .035 wire in short-circuit and C25: 155–170 A, 19–22 V, .035" wire at 245–290 IPM, C25 at 30–35 CFH. Run it in more than one pass and check fusion on a test piece, because that is the top of what .035 short-circuit can do. With .045" wire in spray and 90/10 gas: 260–300 A, 26–28 V, .045" wire at 310–380 IPM, C10 at 35–45 CFH, flat or horizontal. For vertical-up and overhead, start with the settings for one thickness thinner. That means less wire speed (and so fewer amps) and about a volt less than flat. Set wire speed first, then trim voltage until the arc sounds like bacon frying.
Should I use C25 or straight CO2 for MIG welding?
C25 (75/25 Ar/CO2) for most work. It gives a smoother arc, less spatter, and a flatter bead profile. Straight CO2 costs less and penetrates deeper, but the arc is rougher and you will spend more time grinding. Use CO2 when you are burying heavy root passes in thick plate and nobody will see the bead. Most fab shops standardize on C25.
When should I switch from short-circuit to spray transfer?
When the material is 1/4 inch or thicker and you can weld flat or horizontal. Spray gives you more metal per hour with almost no spatter, but it dumps a lot of heat into the part. You need enough amps to clear the transition for your wire: about 175 A for .035 and 215 A for .045 with 90/10 gas. Spray needs at least 82% argon (Lincoln puts the limit at 18% CO₂). Past that, the CO₂ breaking down in the arc shoves the droplet around and you get globular transfer, not spray. C25 has too much CO₂ to spray, so run 90/10 or 95/5 Ar/CO₂ on steel and 98/2 Ar/O₂ on stainless. Below the transition you get globular transfer, which is the worst of both worlds.
Do I need a spool gun for MIG welding aluminum?
You need either a spool gun or a push-pull setup. Aluminum wire is soft and will bird-nest (tangle up) inside a standard MIG liner on anything longer than about 10 feet. A spool gun puts the wire spool right at the gun so it only feeds a few inches. Push-pull systems use a motor at both ends. Most small shops go with a spool gun. They cost less and work fine for occasional aluminum jobs.
What gas do I use for MIG welding stainless steel?
For short-circuit on thin stainless, use tri-mix: 90% helium / 7.5% argon / 2.5% CO2. The helium adds heat and makes the puddle wet out flat, and the CO2 is kept low so the weld does not pick up carbon. For spray on thicker stainless, switch to 98% argon / 2% oxygen. Never use C25 on stainless. That much CO2 puts carbon in the weld and costs you corrosion resistance.
Why is my MIG weld popping and sputtering?
Usually voltage is too low for the wire speed you are running. The wire is hitting the puddle before it melts, causing the arc to short and pop. Turn the voltage up 1–2 volts and see if it smooths out. Other causes: bad ground clamp connection, dirty base metal, gas flow too low (porosity pops), or the wrong gas for the transfer mode. If you are running CO2 and it sounds like a machine gun, that is just how CO2 sounds. Switch to C25.
What is the best wire size for general MIG welding?
.035 covers the widest range in most shops, from 18 gauge sheet up to 1/4" plate in short-circuit. On plate that thick it takes multiple passes and good technique to avoid cold lap. If you mostly do thin gauge auto body or HVAC work, .030 gives better control. If you are welding 1/4 and up every day, .045 in spray lays down a lot more metal per pass. Most fab shops stock .035 as their default and keep .030 around for thin stuff.
Other welding settings charts
TIG (GTAW) Settings Chart
Amperage, tungsten, filler rod, cup size, and gas flow.
Stick (SMAW) Settings Chart
Electrode amperage, polarity, and rod selection by application.
Other tools in the Tack Box
Welding Shop Rate Calculator
What should you charge per hour? Break-even and recommended rate.
Welding Cost Calculator
Cost per inch of weld: labor, filler, gas, and markup by process.
Metal Weight Calculator
Plate, pipe, bar, tube. Steel, aluminum, stainless, brass.
Gas Usage Calculator
Cylinder count and cost for a project. MIG, TIG, flux-core.
Filler Metal Calculator
Pounds of wire or rod for a joint. Spool count and cost.
Job Pricing Calculator
Build a bid from scratch: tasks, materials, overhead, margin.
Welding Quote Calculator
Build a customer-ready quote: work lines, materials with markup, PDF.
Wire & Gas Selection Guide
Which wire and shielding gas for your process and base metal.
Welding Symbol Chart
Every AWS A2.4 weld symbol. Searchable with visual diagrams.
Why shops choose Bead Board
Free Welding Quote Template (PDF)
One-page quote sheet with a filled-in example. No email required.
Bead Board vs. Spreadsheets
Why shops outgrow Excel for job tracking.
Bead Board vs. Paper & Notebooks
Paper loses jobs. Software does not.
Mobile Welder App
Native on iPhone and Android. Works offline in the field.