MIG Welding Guide — Settings, Technique & Troubleshooting

Complete MIG welding guide: settings charts by material thickness, shielding gas selection, wire types, technique for all positions, and troubleshooting common MIG problems.

MIG welding (GMAW, Gas Metal Arc Welding) uses a continuously fed solid wire electrode and external shielding gas to join metals. It’s the most widely used welding process in manufacturing and fabrication because of its speed, ease of use, and adaptability to automation.

The process runs on DCEP (reverse polarity). A power supply delivers constant voltage while a wire feeder pushes electrode wire through a cable and out the gun at a set speed. Shielding gas flows through the same nozzle to protect the weld pool from atmospheric contamination. That combination of automatic wire feed and gas shielding makes MIG the fastest manual arc process for most shop applications.

Transfer Modes

MIG operates in several transfer modes, each suited to different material thicknesses and positions:

  • Short circuit — Low heat, low spatter. Best for thin material (24 gauge to 3/16") and out-of-position work. Wire touches the puddle, shorts, and transfers metal in rapid cycles.
  • Globular — Higher voltage than short circuit. Large droplets transfer across the arc. More spatter, limited to flat and horizontal. Rarely used intentionally.
  • Spray transfer — High voltage, high wire speed. A steady stream of tiny droplets crosses the arc. Highest deposition rate but restricted to flat and horizontal positions. Requires argon-rich gas (85%+ argon).
  • Pulsed spray — The machine alternates between high peak current and low background current. Gets spray-transfer quality in all positions with less heat input. Requires a pulse-capable power supply.

What MIG Welds Best

MIG handles mild steel, stainless steel, and aluminum. Mild steel with C25 gas is the bread-and-butter application. Aluminum MIG requires a spool gun or push-pull gun, 100% argon, and 4043 or 5356 wire. Stainless needs tri-mix or 98/2 argon/CO2 gas and ER308L or ER316L wire.

Material thickness range runs from 24-gauge sheet metal (short circuit, 0.023" wire) up to 1/2" plate (spray transfer, 0.045" wire). For anything over 1/2", flux-cored welding is generally faster and more economical.

MIG Welding Settings Quick Reference

For detailed settings by material thickness, see the MIG welding settings chart or use the MIG welding calculator.

Articles in This Section

The guides below cover every aspect of MIG welding, from basic settings and gas selection to advanced technique and troubleshooting. Start with settings and gas types if you’re new to MIG, or jump to a specific topic.

All Articles

Can You MIG Weld Cast Iron? When and How to Do It Right

MIG welding cast iron is possible with nickel wire and proper technique. Learn preheat requirements, wire selection, settings, and how to prevent cracking on gray, ductile, and malleable cast iron.

10 min read

MIG Welding Thin Sheet Metal Without Burn-Through

How to MIG weld thin sheet metal (22 gauge to 16 gauge) without burning through. Settings, wire size, technique, and machine setup for thin steel, including stitch welding and heat sinks.

9 min read

Vertical MIG Welding: Uphill vs Downhill Technique

How to MIG weld vertical joints. Uphill (vertical up) vs downhill (vertical down) technique, settings, weave patterns, and when to use each method. Includes settings by thickness.

11 min read