WeldMaster Flux core welding settings and polarity: gasless vs dual shield
Loading a gasless spool on a machine wired for solid wire produces spatter like a sparkler. The fix: gasless (self-shielded) wire such as E71T-11 runs DCEN, electrode negative, no gas. Dual-shield E71T-1 runs DCEP, electrode positive, with C25 or 100% CO₂. WeldMaster's Flux-Core calculator (Pro) gives amperage, voltage and wire speed for each — for .035 gasless wire that's 100 – 200 A and 14.0 – 17.0 V.
Which polarity does flux core need?
It depends on the wire, not on the machine. Self-shielded wire makes its own shielding from the flux and runs electrode negative. Gas-shielded, or dual-shield, wire runs electrode positive, like solid MIG wire.
Many small machines come wired for solid wire by default. Load a gasless spool and the first thing to check, before anything else, is the polarity lead. The label on the spool states the polarity, and it always wins over what the machine happened to be set to.
| Wire | Polarity | Gas |
|---|---|---|
| Self-shielded E71T-11 | DCEN (electrode negative) | None (self-shielded) |
| Dual-shield E71T-1 | DCEP (electrode positive) | C25 or 100% CO₂, 35.0 – 45.0 CFH |
What is the gasless flux core settings chart?
For self-shielded wire, WeldMaster uses a fixed band for each wire diameter, and the band does not change with thickness. The bands are wide because one wire covers everything from light sheet to multi-pass plate.
| Wire | Amperage | Voltage | Wire feed |
|---|---|---|---|
| .030 | 40 – 160 A | 13.0 – 16.0 V | 75.6 – 302.4 ipm |
| .035 | 100 – 200 A | 14.0 – 17.0 V | 144.0 – 288.0 ipm |
| .045 | 150 – 250 A | 15.0 – 19.0 V | 155.2 – 258.8 ipm |
Wire feed is the amperage times the solid-wire burn factor minus 10%, because flux-cored wire melts off faster per amp. In Metric, the .035 row reads 3.7 – 7.3 m/min.
What are dual-shield flux core settings by plate thickness?
Dual-shield ranges do follow the plate. The app scales the center from 150 A at 3/16" to 300 A at 1/2", takes ±10% for the amperage window and ±1 V around the voltage center.
| Plate | Wire | Amperage | Voltage | Wire feed |
|---|---|---|---|---|
| 1/4" | .035 | 162 – 198 A | 24.0 – 26.0 V | 233.3 – 285.1 ipm |
| 3/8" | .045 | 216 – 264 A | 26.0 – 28.0 V | 223.6 – 273.2 ipm |
| 1/2" | .045 | 270 – 330 A | 28.0 – 30.0 V | 279.4 – 341.5 ipm |
Gas flow is 35.0 – 45.0 CFH (16.5 – 21.2 L/min) with either gas.
How do you set up flux-core in WeldMaster?
- Open Flux-Core from Calculators. It is a Pro calculator; in the free version the card shows a lock and opens the upgrade screen.
- Under Process, choose Self-Shielded (E71T-11) for gasless wire or Dual-Shield (E71T-1) for gas-shielded wire.
- Set the thickness and pick your Wire Size: .030, .035 or .045.
- For dual-shield, pick the Shielding Gas: C25 or 100% CO₂. For gasless wire, Shielding shows None (self-shielded).
- Read Amperage, Voltage, Wire Feed, Gas Flow and Polarity, then set the polarity lead on the machine before you strike an arc.
- Tap Save to keep the settings that worked in My Setups.
What are flux core welding settings for 1/4" steel?
On 1/4" plate the two wire types give different answers. Gasless .035 keeps its full 100 – 200 A and 14.0 – 17.0 V band, so start near the middle and tune on a test piece. Dual-shield .035 with C25 narrows to 162 – 198 A and 24.0 – 26.0 V, because it is sized to the plate.
The app warns in two cases: over 3/8", self-shielded wire needs multiple passes and dual-shield may suit better; under 3/16", dual-shield is heavy, and self-shielded wire or MIG is easier to control.
What are common flux-core mistakes?
- Wrong polarity is the classic gasless problem: heavy spatter and a poor bead. Check the lead before you touch voltage or wire speed.
- Narrow a wide gasless band with a test bead: set the voltage inside the window, then raise the wire speed until the arc sounds steady.
- Chip all the slag between passes. Slag left in the joint causes lack of fusion on the next pass.
- Do not add gas to self-shielded wire hoping for a cleaner weld; the flux already does the shielding.
Questions and answers
Is gasless flux core DCEN or DCEP?
Why is the gasless range so wide?
Can I weld 1/2" plate with gasless flux core?
Is the flux-core calculator free?
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