Electrode comparison
ER70S-6 vs E7018
ER70S-6 fills faster with no slag and is easier to learn; E7018 needs no gas, tolerates wind and dirt, and is the low-hydrogen rod codes call for.
ER70S-6 vs E7018 at a glance
| ER70S-6 | E7018 | |
|---|---|---|
| AWS specification | AWS A5.18/A5.18M | AWS A5.1/A5.1M |
| Process | MIG (GMAW) | Stick (SMAW) |
| Form | Solid wire | Covered electrode |
| 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 -20 °F (27 J at -29 °C) |
| Polarity | DCEP | DCEP, AC |
| Positions | Flat, Horizontal, Vertical, Overhead | Flat, Horizontal, Vertical, Overhead |
| Penetration | Medium, varies strongly with gas and transfer mode | Medium |
| Deposition rate | High, continuous feed with no stub loss | High |
| Coating / core | None — bare solid wire, often copper coated for feedability and contact | Low-hydrogen potassium with iron powder |
| Slag | None; silicon islands float to the surface and are brushed off | Heavy, brown-glassy, releases cleanly when run correctly |
| Shielding gas | 75% argon / 25% CO2 (C25) | None — self-shielding |
| Storage | Keep spools dry and covered. Bare wire rusts, and rusty wire means porosity and feed problems. | Low-hydrogen rods must be kept dry. Hermetically sealed until opened, then held in a rod oven at 250–300 °F (120–150 °C). |
| Primary use | General fabrication and shop welding on carbon steel | Structural steel erection, bridges and buildings |
Which should you use?
Both deposit 70 ksi weld metal, so this is really a process comparison. MIG with ER70S-6 is faster, leaves no slag, has a much shorter learning curve and suits production work on clean steel indoors. Stick with E7018 needs no gas bottle, works in wind and rain, tolerates surface contamination and rough fit-up far better, and its low-hydrogen deposit with -20 °F toughness is what most structural procedures specify. The choice usually comes down to where the work is and what the code says.
Choose ER70S-6 when
- Indoor shop fabrication on clean steel
- High-volume production welding
- Sheet and light plate
- Welders new to the trade
Choose E7018 when
- Field welding, wind and weather
- Structural and coded joints requiring low hydrogen
- Rusty, painted or poorly fitted steel
- Maximum portability
Amperage compared
| Diameter | ER70S-6 | E7018 |
|---|---|---|
| 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 | — |
| 0.045 in (1.2 mm) | 120–320 A | — |
| 3/32 in (2.4 mm) | — | 70–120 A |
| 1/8 in (3.2 mm) | — | 110–165 A |
| 5/32 in (4.0 mm) | — | 150–220 A |
| 3/16 in (4.8 mm) | — | 200–275 A |
| 7/32 in (5.6 mm) | — | 260–340 A |
Ranges are typical starting points. Diameters listed for only one electrode are shown as — for the other.
ER70S-6 vs E7018 — common questions
Is MIG or stick stronger?
Both deposit 70 ksi class weld metal. On a correctly designed and executed joint neither is stronger — but short-circuit MIG can produce cold lap on thick material, which is why codes often restrict it.
Which is better for a beginner?
MIG. The gun maintains arc length automatically, so a usable bead comes much sooner. Stick demands manual arc length control from the first minute.
Can I MIG weld structural steel?
Yes, under a qualified procedure — usually in spray or pulsed transfer rather than short circuit. Many structural codes restrict short-circuit GMAW because of the cold lap risk.
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.
E7018
AWS A5.1/A5.1M
E7018 is the low-hydrogen structural rod — 70 ksi tensile, tough at -20 °F, all positions, and the default electrode on most structural and code work.