Flux-Core Welding Settings: Voltage, Wire Speed, and Polarity Charts

Flux-core welding settings center on three variables: voltage, wire feed speed (which controls amperage), and stick-out distance. For 0.035" E71T-11 self-shielded wire on 3/16" steel, start at 18V with 250 IPM wire speed and 3/4" stick-out on DCEN polarity. The charts below cover every common wire diameter and thickness combination for both self-shielded and gas-shielded flux-core wire.

Unlike solid MIG wire where you dial voltage and wire speed independently, FCAW parameters are more sensitive to stick-out changes. A quarter-inch shift in your gun distance changes amperage by 20-25 amps. Master consistent stick-out first, then fine-tune voltage and wire speed.

Self-Shielded Wire Settings (DCEN)

These settings apply to E71T-11 and similar self-shielded wires. All run on DCEN (electrode negative) polarity.

0.030" Self-Shielded Wire (E71T-GS)

Note: 0.030" wire is limited to thin material. Maximum single-pass thickness is about 3/16". For heavier work, step up to 0.035" or 0.045" wire.

0.035" Self-Shielded Wire (E71T-11)

0.045" Self-Shielded Wire (E71T-11)

Gas-Shielded Wire Settings (DCEP)

These settings apply to E71T-1 and similar gas-shielded wires with 75/25 argon/CO2 or 100% CO2 shielding gas at 35-45 CFH flow rate. All run on DCEP (electrode positive) polarity.

0.035" Gas-Shielded Wire (E71T-1)

0.045" Gas-Shielded Wire (E71T-1)

1/16" Gas-Shielded Wire (E71T-1 / E70T-1)

Polarity Reference by Wire Type

Polarity is the single most important setting to get right. Wrong polarity produces terrible welds that look nothing like the charts above would suggest.

For a detailed breakdown of each wire type and its applications, see the flux-core wire selection guide.

How Stick-Out Affects Settings

Contact-tip-to-work distance (CTWD), commonly called stick-out, has a bigger effect on FCAW parameters than most welders realize. Flux-core wire is resistively heated as it travels from the contact tip to the arc. Longer stick-out means more resistance, more preheating of the wire, and lower actual welding amperage.

Here’s how a 1/4" change in stick-out affects a typical 0.045" E71T-11 setup:

• 3/4" stick-out: ~200 amps at 250 IPM wire speed
• 1" stick-out: ~180 amps at 250 IPM wire speed
• 1-1/4" stick-out: ~160 amps at 250 IPM wire speed

Same wire speed, 40 amps of difference. That’s why consistent gun distance matters more in FCAW than in solid-wire MIG welding. If you can’t hold a steady stick-out, your amperage wanders and your weld quality suffers.

Stick-Out by Wire Type

• Self-shielded 0.030": 3/8" to 3/4"
• Self-shielded 0.035": 5/8" to 1"
• Self-shielded 0.045": 3/4" to 1-1/4"
• Gas-shielded 0.035": 1/2" to 3/4"
• Gas-shielded 0.045": 5/8" to 1"
• Gas-shielded 1/16": 3/4" to 1-1/4"

Position Adjustments

The charts above show flat-position settings. Adjust for other positions:

Vertical-up: Reduce wire feed speed 10-15% and drop voltage 1-2V from flat settings. The slower travel and uphill technique need a cooler, stiffer puddle to prevent sagging. See FCAW welding positions for position-specific technique.

Horizontal: Reduce wire speed 5-10% and keep voltage at the lower end of the flat range. A slight downward gun angle (5-10 degrees) fights gravity sag.

Overhead: Reduce wire feed speed 10-15% and drop voltage 1-2V. Keep a tight stick-out and move steadily. If the puddle drips, you’re too hot.

Gas Flow Settings (Gas-Shielded Only)

Gas flow rate for FCAW-G runs 35-45 CFH depending on joint type, nozzle size, and drafts:

• Tight joints, no drafts: 35 CFH
• Open joints, mild air movement: 40 CFH
• Large nozzles, 1/16"+ wire: 45 CFH

Don’t exceed 50 CFH. Excessive gas flow creates turbulence at the nozzle exit, pulling in atmospheric contamination. More gas isn’t better. If you’re getting porosity and think it’s a gas coverage issue, check for drafts, leaks in the gas line, and spatter buildup inside the nozzle before increasing flow.

Dialing In Your Settings: Step by Step

1. Verify polarity. Check wire packaging for DCEN or DCEP. Swap leads if needed.
2. Set stick-out. Mark the correct distance on your nozzle with tape if it helps build the muscle memory.
3. Start with the chart settings for your wire diameter and material thickness.
4. Run a 4-6 inch test bead on scrap of the same thickness.
5. Read the bead:
   • Excessive spatter: voltage too low or too high (try adjusting 0.5V in either direction)
   • Bead too convex/ropy: voltage too low, increase 0.5-1V
   • Bead too flat or concave: voltage too high, decrease 0.5-1V
   • Poor penetration: wire speed too low, increase 10-20 IPM
   • Burn-through: wire speed too high or travel speed too slow
6. Adjust one variable at a time in small increments.
7. Listen to the arc. A properly tuned FCAW arc has a steady, smooth crackling sound. A harsh, loud crackling means too much voltage. A sputtering, popping arc means not enough voltage.

Troubleshooting Settings Issues

Bead looks good but has porosity inside: Stick-out too long (especially self-shielded), contaminated base metal, or wind blowing away shielding (gas-shielded). Shorten stick-out, clean the joint, or block drafts.

Wire burns back to the contact tip on start: Wire feed speed too slow for the voltage, or you’re starting with the gun too far from the work. Start with the wire nearly touching the workpiece, pull the trigger, then establish your stick-out as the arc stabilizes.

Excessive spatter on self-shielded wire: Confirm DCEN polarity first. If polarity is correct, voltage is usually the issue. FCAW has a narrow voltage sweet spot. Try adjusting 0.5V up and 0.5V down from your current setting and compare the spatter on test beads. For more spatter solutions, see spatter reduction techniques.

Arc wanders erratically: Worn or wrong-size contact tip, wire not feeding smoothly (check drive roll tension and liner condition), or the wire spool is damaged/tangled.

Weld profile changes during the bead: Your stick-out is changing as you weld. This is the most common operator error in FCAW. Practice maintaining consistent gun distance throughout the entire bead length.

Multi-Pass Settings Adjustments

For material thicker than the single-pass range of your wire, you’ll need multiple passes. Multi-pass FCAW requires slight settings adjustments between root, fill, and cap passes.

Root pass: Use settings at the low end of the chart range for your thickness. A slightly cooler puddle prevents burn-through on the first pass. Reduce wire speed 5-10% from the single-pass setting.

Fill passes: Run at or slightly above the chart midpoint. You’re welding into a groove formed by previous passes, so heat buildup is less of a concern. Full chart settings work well. Interpass temperature should stay below 500F for most carbon steel work.

Cap pass: Use the high end of the voltage range to get a flatter, wider bead profile. Increase voltage 0.5-1V above the fill pass setting. Slow travel speed slightly for a smoother bead appearance.

For detailed multi-pass technique, see flux-core welding thick steel.

Shielding Gas Effects on Settings (Gas-Shielded Wire)

The two common shielding gases for FCAW-G produce different arc characteristics at the same voltage and wire speed:

100% CO2: Deeper penetration, more spatter, broader arc. CO2 produces a more violent arc with more spatter than argon mixes. Voltage typically needs to be 1-2V higher with CO2 to smooth out the arc. Better for thick material where penetration matters more than appearance.

75/25 Argon/CO2: Smoother arc, less spatter, shallower penetration. The argon content stabilizes the arc and reduces spatter. Slightly lower voltage works well. Better for thinner material and visible welds where appearance matters.

If you switch between gases, adjust voltage and wire speed accordingly. Settings optimized for 75/25 will be too hot on CO2, and CO2 settings will be too cold on 75/25. The charts above assume 75/25 for gas-shielded settings. For 100% CO2, increase wire speed 5-10% and voltage 1-2V from the chart values.