WeldMaster MIG vs flux core welding: which one for which job?
Use MIG on thin, clean metal indoors and flux core when it is windy, dirty or thick. The settings differ more than most people expect. Gas, polarity and amps all change.
Same machine, different wire
Plenty of people run both on one box. You change the wire and the polarity, and dual-shield wire still needs the bottle. So it can be a spool swap, not a new machine, which is why the question comes up.
Which one for the job in front of you?
- Thin sheet, 16 gauge and under, clean steel, indoors: MIG. Solid wire with C25 is the one the free MIG screen covers, and its settings scale down to 16 gauge.
- Outdoors or in a draft: self-shielded flux core. It carries its own shielding, so wind does not blow the gas off the puddle. WeldMaster's own note says it is good for windy field work and out-of-position.
- Thick plate and fast deposition: dual-shield flux core. The app calls it high deposition, and it runs gas.
These are not ranked by strength here. The app has no strength data, and the wire class and your procedure decide that. It only shows where each process is meant to be used.
The settings side by side
Comparing 3/16" mild steel with .035 wire, from the MIG and Flux-Core screens:
| MIG, C25 | Flux core, Self-Shielded (E71T-11) | Flux core, Dual-Shield (E71T-1) with C25 | |
|---|---|---|---|
| Amperage | 169 – 206 A | 100 – 200 A | 135 – 165 A |
| Voltage | 18.5 – 20.5 V | 14 – 17 V | 23 – 25 V |
| Wire feed | 270.0 – 330.0 ipm | 144.0 – 288.0 ipm | 200.0 – 237.6 ipm |
| Gas flow | 20.0 – 25.0 CFH | none | 35.0 – 45.0 CFH |
| Polarity | DCEP | DCEN | DCEP |
Two things stand out. Self-shielded wire runs the opposite polarity to MIG, so the leads get swapped. And dual-shield eats far more gas, 35 – 45 CFH against 20 – 25 for MIG short-circuit.
Where to find each in WeldMaster
- MIG is under Calculators and free. It handles solid wire in Mild Steel, Stainless and Aluminum.
- Flux-Core is under Calculators and is Pro. Under Process pick Self-Shielded (E71T-11) or Dual-Shield (E71T-1).
- Read Amperage, Voltage, Wire Feed, Gas Flow and Polarity on each. Compare them for your thickness.
What the app will not tell you
The self-shielded flux-core range depends only on the wire diameter. Changing the thickness from 16 gauge to 3/8" does not move the numbers; a multi-pass warning appeared only above 3/8". On thin steel it will show 100 – 200 A for .035 wire, and that is not an answer for sheet. For thin metal use the MIG screen, which does scale with thickness. The dual-shield result warns that it is heavy under 3/16".
There is no 'which should I use' button. You get two sets of numbers and one-line notes, and the call is yours. A reasonable approach: on clean steel indoors, stick with MIG, and only buy Pro for Flux-Core if wind is a regular problem. MIG is free, so try the thin-metal answer there first.
Questions and answers
Is MIG better than flux core?
Is MIG or flux core easier for a beginner?
Is MIG and flux core the same?
Can I use flux core on thin metal?
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- MIG Settings for 1/8-Inch Mild Steel With .035 Wire · WeldMaster
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