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ER70S-6 MIG welding wire is the standard solid wire for gas-shielded welding of mild steel. This listing is an ER70S-6 0.035 in. 33 lb spool aimed at shops that weld often. It is worth considering if your machine takes a 12 inch spool and you use plenty of wire. Skip it if you weld occasionally, because wire can rust over time and a smaller spool is easier to store and mount. This review is based on the Amazon listing and standard AWS classification knowledge, not hands-on testing.
ER70S-6 0.035 in. 33 lb Spool at a Glance
| Item | Details |
|---|---|
| Classification | AWS ER70S-6, solid carbon steel wire |
| Diameter | 0.035 in. |
| Spool weight | 33 lb, per the listing |
| Finish | Copper-coated, per the listing |
| Shielding gas | CO2 or argon/CO2 mixes |
| Positions | All-position |
| Typical tensile class | 70,000 psi minimum |
Prices change, so check the current listing. Buy from a seller who shows the classification clearly.
What ER70S-6 Is and Who It Suits
ER70S-6 contains manganese and silicon, which help clean the weld pool and tolerate light mill scale. It is a common choice for structural steel, fabrication, farm repair, auto and general shop work.
It does not remove the need to clean metal. Heavy rust, oil and paint still cause porosity, so grind to clean metal where it matters. The wire also needs shielding gas; for gasless welding, use a flux-core wire instead.
How to Check the Spool and Wire Fit Your Machine
- Spool size. A 33 lb spool is typically 12 inches in diameter. Most hobby machines take 8 inch spools or smaller. Check the manual, or buy a smaller spool.
- Hub and weight. A heavy spool needs a sturdy spindle and a decent hub. Verify the arbor hole size and the hub.
- Wire diameter. 0.035 in. needs a matching contact tip, drive rolls (V-groove for solid wire) and liner.
- Machine range. 0.035 in. wire suits many light to mid-range machines. Check the amperage range of your welder for the thickness you weld.
- Shielding gas. You need a cylinder and regulator. A 75/25 argon/CO2 mix is common for mild steel.
- Wire quality. Check the listing for a clear brand, classification and spool winding. Poor winding causes tangles.
Pros and Limitations
Pros
- The most common choice for mild steel MIG welding.
- A large spool lowers cost per pound for heavy users and means fewer changes.
- Works with common shielding gases.
Limitations
- The 33 lb size does not fit many hobby machines.
- Needs gas, so it is less convenient outdoors than flux-core.
- Not for aluminum or stainless.
- Wire can rust if stored in humid conditions.
Using and Storing the Wire
- Keep wire in a dry place. Cover the spool when not in use, and consider a bag with desiccant.
- Use proper drive roll tension. Too much flattens the wire; too little slips.
- Keep the liner clean and replace worn contact tips.
- Set the gas flow per your manual. Too low gives porosity; too high wastes gas and can cause turbulence.
- Wear a helmet with the correct shade (typically #10 to #13 at mid amps; check the filter chart), gloves and flame-resistant clothing.
- Ventilate the area. Do not weld galvanized or coated steel without proper ventilation and respiratory protection.
- Do not weld on closed containers that held fuel.
Alternatives and Related Guides
- No gas? See the E71T-GS gasless wire review or the AWT flux core welding wire review.
- Smaller spool: 0.023 in. solid MIG wire spool review.
- Aluminum? Read the AZZUNO ER5356 aluminum MIG wire review.
- Spool fit: wire spool adapter hub review.
- Same size and spool: ELSHINE ER70S-6 .035 in, 33 lb review or the 33 lb roll ER70S-6 review.
Frequently Asked Questions
What does ER70S-6 mean?
ER means the wire can be used as an electrode or a rod, 70 is the minimum tensile strength class of 70,000 psi, S means solid wire, and 6 refers to the chemistry. The -6 grade has extra deoxidizers (manganese and silicon) that help on lightly rusty or scaled steel.
What shielding gas should I use with ER70S-6?
Common choices are 75% argon / 25% CO2 for a smoother arc and less spatter, or 100% CO2 for deeper penetration with more spatter. It is a gas-shielded solid wire, so do not use it without gas, and check your machine manual for settings.
Can I weld aluminum or stainless with ER70S-6?
No. ER70S-6 is for mild and low-alloy carbon steel. Aluminum needs aluminum wire and 100% argon. Stainless needs a stainless filler, often with a tri-mix or argon blend. Using the wrong wire gives weak, defective welds.
Will a 33 lb spool fit my welder?
Only if your wire feeder takes large 12 inch spools with a compatible hub. Many hobby machines are made for 2 lb to 10 lb spools. Check your manual, or use a spool adapter, and note that the spool is heavy, so a stable mount matters.
Verdict
ER70S-6 is the sensible default solid wire for mild steel. Buy this large spool only if your feeder takes it and you will use it up before it rusts.
