Electrode comparison
ER70S-6 vs E71T-1
ER70S-6 is solid wire with no slag and a cleaner finish; E71T-1 is flux-cored, deposits considerably faster and penetrates deeper on thick plate.
ER70S-6 vs E71T-1 at a glance
| ER70S-6 | E71T-1 | |
|---|---|---|
| AWS specification | AWS A5.18/A5.18M | AWS A5.20/A5.20M |
| Process | MIG (GMAW) | Flux-Cored (FCAW) |
| Form | Solid wire | Tubular wire |
| Tensile strength (min) | 70 ksi | 70 ksi |
| Yield strength (min) | 58 ksi | 58 ksi |
| Elongation (min) | 22% | 22% |
| Impact toughness | 20 ft·lb at -20 °F (27 J at -29 °C) | 20 ft·lb at 0 °F (27 J at -18 °C); -1J and -1M grades extend this to -20 °F |
| Polarity | DCEP | DCEP |
| Positions | Flat, Horizontal, Vertical, Overhead | Flat, Horizontal, Vertical, Overhead |
| Penetration | Medium, varies strongly with gas and transfer mode | Medium to deep |
| Deposition rate | High, continuous feed with no stub loss | Very high — roughly twice the rate of a comparable stick electrode |
| Coating / core | None — bare solid wire, often copper coated for feedability and contact | Rutile flux core inside a mild steel sheath |
| Slag | None; silicon islands float to the surface and are brushed off | Fast-freezing rutile slag that supports the puddle out of position and peels readily |
| Shielding gas | 75% argon / 25% CO2 (C25) | 100% CO2 or 75% argon / 25% CO2 |
| Storage | Keep spools dry and covered. Bare wire rusts, and rusty wire means porosity and feed problems. | Keep dry. The flux core absorbs moisture through the seam of the wire, and damp wire means porosity and hydrogen cracking. |
| Primary use | General fabrication and shop welding on carbon steel | Structural steel fabrication and erection |
Which should you use?
Both run on the same machine with the same gas, both deposit 70 ksi weld metal, and both need shelter from wind. The difference is what the wire is made of. Solid ER70S-6 leaves no slag, gives a tidy bead and costs less per pound — ideal for sheet, light plate and anything where cleanup time matters. Tubular E71T-1 carries flux inside, so it deposits at a considerably higher rate, penetrates deeper at the same current, and its fast-freezing slag supports the puddle for genuine all-position welding at high amperage. On plate over about 1/4 in, flux core usually wins on throughput.
Choose ER70S-6 when
- Sheet metal and thin plate
- Work where no slag cleanup is a real advantage
- Lower wire cost on high-volume light fabrication
- Automotive and cosmetic welds
Choose E71T-1 when
- Plate over about 1/4 in
- Structural fabrication and heavy equipment
- All-position welding at high deposition rates
- Joints needing deeper penetration
Amperage compared
| Diameter | ER70S-6 | E71T-1 |
|---|---|---|
| 0.023 in (0.6 mm) | 30–90 A | — |
| 0.030 in (0.8 mm) | 50–180 A | — |
| 0.035 in (0.9 mm) | 70–220 A | 90–250 A |
| 0.045 in (1.2 mm) | 120–320 A | 150–350 A |
| 0.052 in (1.4 mm) | — | 180–400 A |
| 1/16 in (1.6 mm) | — | 200–450 A |
Ranges are typical starting points. Diameters listed for only one electrode are shown as — for the other.
ER70S-6 vs E71T-1 — common questions
Is flux core stronger than solid MIG wire?
Both deposit 70 ksi class weld metal on carbon steel. Flux core penetrates deeper and fills faster, which suits thick plate, but neither is inherently stronger on a properly designed joint.
Can I run both on the same machine?
Yes, on DCEP with the same CO2 or 75/25 gas. Change to knurled drive rolls for the tubular wire and lengthen the contact tip to work distance.
Which produces more fume?
E71T-1, by a clear margin. Flux-cored processes generate noticeably more fume than solid wire, so ventilation matters more.
Full specifications
ER70S-6
AWS A5.18/A5.18M
ER70S-6 is the default solid MIG wire for carbon steel — high silicon and manganese let it weld over mill scale and light rust with good wetting.
E71T-1
AWS A5.20/A5.20M
E71T-1 is gas-shielded flux-cored wire — the high-deposition, all-position production workhorse for structural steel, combining FCAW speed with a smooth spray-like arc.