Choosing MIG Wire: ER70S-6, E71T-GS, ER308L and Aluminium
Gas or gasless? Solid or flux-cored? A straight guide to picking welding wire that actually suits your machine and your site.
Solid wire vs flux-cored — the first decision
Solid wire needs shielding gas. No gas, no weld — just porous rubbish. Flux-cored gasless wire makes its own shielding as the flux burns, so it works outdoors. That one difference decides most purchases.
ER70S-6 — the default mild steel wire
- Solid wire for mild steel; needs CO₂ or an 80/20 argon-CO₂ mix
- Extra deoxidisers let it cope with mill scale and light rust
- Clean, fast, very little spatter with the right settings
- Use for: indoor production, fabrication, sheet and plate
Product: ER70S-6 MIG Wire
E71T-GS — gasless, for the site
- Self-shielded flux-cored — no gas cylinder at all
- Handles wind, which kills solid-wire MIG outdoors
- Runs DCEN (electrode negative) — check your machine polarity, this is the #1 mistake
- Leaves slag to chip, and it is a single-pass wire
- Use for: outdoor repairs, site work, thin steel where dragging a cylinder is impractical
Product: E71T-GS Flux-Cored Wire
ER308L — stainless
For 304/304L stainless. Use argon-based gas (commonly a tri-mix or 98/2 Ar-CO₂) — pure CO₂ will wreck the corrosion resistance you are paying for. Product: ER308L Wire
Aluminium — ER4043 vs ER5356
| ER4043 | ER5356 | |
|---|---|---|
| Alloy | Silicon | Magnesium |
| Feel | Softer, flows well, less cracking | Stiffer — feeds better through a liner |
| Strength | Lower | Higher |
| Anodising | Turns dark | Matches better |
Aluminium needs pure argon, a clean surface and ideally a spool gun or push-pull — it is soft and it birdnests easily. Product: Aluminium Wire (ER4043 / ER5356)
Two things people get wrong
- Liner and tip must match the wire. A steel liner shreds aluminium wire.
- Store it dry. A rusty or damp spool gives porosity, and you will blame the machine.
