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What shielding gas is most common for MIG welding aluminum?

100% argon.

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  1. 100% carbon dioxide
  2. 100% argon ✔
  3. 75% argon, 25% carbon dioxide

Why: Aluminum is MIG welded with pure argon. The CO2 mixes used on steel are the wrong choice for aluminum.

Huh, didn't know that: Miller says a helium-blend shielding gas can help reduce hydrogen porosity when welding aluminum.

The dad joke
Helium walks into a bar. The bartender says, "We don't serve noble gasses here." Helium doesn't react.
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References

Answer: 100% argon. Aluminum is MIG welded with pure argon. The CO2 mixes used on steel are the wrong choice for aluminum.

  1. Best Gas for MIG in DIY (Miller) www.millerwelds.com/en-us/resources/knowledge-hub/mig-welding/how-to/what-type-of-gas-is-best-for-mig-welding-in-diy-applications
    The most common gas used for MIG welding aluminum is 100% argon.
    Checked 2026-10-10.
  2. Welding Aluminum vs. Steel (Miller) www.millerwelds.com/resources/article-library/welding-aluminum-vs-steel-tips-to-improve-your-results
    Using a helium-blend shielding gas can also help reduce hydrogen.
    Checked 2026-10-10.

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Trades & ShopWhat is the most common shielding gas mix for MIG welding mild steel?Trades & ShopWhich argon and CO2 mix does Miller say works well for MIG welding stainless steel?Trades & ShopCompared with 75/25 argon and CO2, what does 100% CO2 shielding gas tend to give?

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