MIG Welding Settings Chart

For 1/8 inch (0.125") mild steel using .030 wire with 75/25 gas, set your voltage to 17-18V and wire speed to 280-320 IPM. This translates to approximately 130-140 amps. For thicker material or multiple passes, you may increase to 19-20V with 320-360 IPM wire speed. Listen for a consistent crackling sound like bacon frying - if it's popping or hissing, adjust your settings.

For 7018 stick welding rods, use approximately 1 amp per thousandth of electrode diameter. A 3/32" (0.094") rod uses 70-100 amps, 1/8" (0.125") uses 90-140 amps, 5/32" (0.156") uses 120-180 amps, and 3/16" (0.188") uses 150-220 amps. Always use DCEP (DC Electrode Positive) polarity with 7018 rods. Start in the middle of the range and adjust based on how the rod burns - if it's sticky, increase amps; if it's burning too fast or undercutting, decrease.

75/25 (75% Argon, 25% CO2) produces cleaner welds with less spatter, smoother bead appearance, and better arc stability. It's ideal for thin materials, automotive work, and applications where appearance matters. 100% CO2 provides deeper penetration and is more economical (about half the cost), but creates more spatter and a rougher bead appearance. Use 75/25 for clean, precise work on thin to medium materials, and 100% CO2 for thicker structural steel where maximum penetration is more important than aesthetics.

Porosity is caused by gas contamination trapped in the weld pool. The most common causes are: dirty base metal (oil, rust, paint, moisture), insufficient gas flow (check regulator is set to 20-25 CFH), wind or drafts blowing away shielding gas, gas leaks in hose or gun connections, contaminated or rusty wire, gun nozzle held too far from work (maintain 3/8" to 1/2" stick-out), and travel speed too fast. To fix it, clean your material thoroughly with a grinder or acetone, check all gas connections with soapy water, shield your work area from wind, and ensure proper gun technique.

Match tungsten diameter to material thickness and amperage range. For steel and stainless steel under 1/8" thick, use 1/16" or 3/32" 2% thoriated (red) or 2% lanthanated (blue) tungsten with DCEN polarity, sharpened to a point. For aluminum, use 1/8" or 3/32" pure tungsten (green) or 2% ceriated (gray) with AC polarity, allowing a ball to form on the tip. As a general rule: 1/16" tungsten for 10-80 amps, 3/32" for 60-150 amps, and 1/8" for 100-250 amps. Thinner tungsten gives better arc control at low amperages.

Reduce MIG welding spatter by: switching from 100% CO2 to 75/25 Argon/CO2 gas, ensuring proper voltage-to-wire-speed balance (too much wire speed causes spatter - increase voltage or decrease wire speed), maintaining correct stick-out distance (3/8" to 1/2"), keeping gun angle at 15-20 degrees, cleaning base metal thoroughly before welding, using quality welding wire, and applying anti-spatter spray on your workpiece and nozzle. If you hear popping sounds, your wire speed is likely too high relative to voltage.

Undercut is a groove melted into the base metal along the weld toe that isn't filled with weld metal, creating a weak point in the joint. It's caused by: excessive amperage or voltage melting too much base metal, travel speed too fast not allowing filler to fill the groove, incorrect gun angle (too steep), arc length too long, or improper weaving technique. Fix undercut by: reducing voltage 1-2V, slowing travel speed, using a 15-20 degree gun angle, maintaining proper arc distance, and pausing briefly at the edges when using a weaving pattern to allow weld metal to fill the toes.