What Gas Does a Mig Welder Use: Essential Guide for Perfect Welds
The short answer: most MIG welders use a 75% argon / 25% CO2 mix (called “C25”) for mild steel, 100% argon for aluminum, and a tri-mix of helium, argon, and CO2 for stainless steel. The gas you pick controls penetration, spatter, bead shape, and how forgiving the arc feels — pick wrong and even good …