MIG Welding
Semi-automatic welding process using a continuously fed solid wire electrode and external shielding gas. Faster than SMAW with less operator skill required. Widely used in manufacturing, fabrication shops, and automotive work.
MIG welding feeds a solid wire electrode continuously through a gun while shielding gas (typically 75% argon / 25% CO2 for mild steel) protects the weld pool from atmospheric contamination. It is the fastest manual arc welding process for mild steel and produces clean welds with minimal slag. MIG requires a gas bottle and is sensitive to wind, which limits outdoor use. Most production fab shops and auto body facilities default to MIG for its speed, ease of use, and consistent weld quality on clean material.
MIG Welding Electrodes
ER70S-6
The standard MIG wire for mild steel. Works on everything from sheet metal to heavy plate. Handles some rust and oil.
ER70S-3
Cleaner MIG wire for clean steel. Less silicon residue than ER70S-6, but less forgiving on dirty metal.
ER80S-D2
80,000 psi MIG wire with molybdenum for welding high-strength low-alloy (HSLA) steels and chrome-moly piping.
MIG Wire Questions
What MIG wire should I use for mild steel?
ER70S-6 is the default MIG wire for mild steel. It handles light mill scale and produces clean welds with standard 75/25 Ar/CO2 shielding gas. ER70S-3 is a lower-cost alternative for clean material.
What size MIG wire should I use?
0.030 inch wire for thin material (up to 3/16 inch). 0.035 inch for general-purpose work on 3/16 to 3/8 inch material. 0.045 inch for thicker material in production settings.
What shielding gas for MIG welding steel?
75% argon / 25% CO2 is the standard mix for mild steel MIG welding. 100% CO2 gives deeper penetration but more spatter. For stainless, use tri-mix or 98/2 Ar/CO2.