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  • Writer's pictureRob Bite

What’s the Best Gas for MIG Welding Aluminum?

Updated: Mar 30, 2023

In a previous blog, we looked at some of the best industrial gases to use for MIG Welding Mild Steel. Another common metal that is worked on in the welding industry is aluminum, and in this blog we’re going to look at the best gases for MIG welding aluminum.

MIG welding aluminum is typically considered to be difficult, and is a very different process from MIG welding mild steel. While MIG welding mild steel relies heavily on carbon dioxide (CO2), MIG welding aluminum uses the industrial gases of argon or helium.

When it comes to these two gases in MIG welding aluminum, they are used either as pure argon, pure helium or various mixtures of both argon and helium.

Why is aluminum welding so difficult?

When aluminum is exposed to the ambient air, a wafer-thin layer of aluminum oxide is formed - giving the metal its silver-grey appearance. However, it’s this same property that makes the metal corrosion-resistant to water, oxygen and a range of chemicals.

This layer of aluminum oxide works to protect the metal, with a melting temperature of 2050°C - far more than that of the 660°C of the actual aluminum itself. Therefore, to prevent the arc and the weld pool from forming a connection during the MIG welding process of the aluminum, the layer must be broken.

If you try to break the aluminum oxide through welding heat, there’s an extremely high chance that the aluminum will melt away as soon as the oxide layer is broken. The oxide layer, therefore, must be removed before the welding begins.

So, what gas should I use when MIG welding aluminum?

The two gases used for MIG welding aluminum are argon or helium. They can be used in their pure form, or as a mixture of both.

Typically, pure argon is the most popular of these gases to use as a shielding gas in MIG welding aluminum. Pure argon is commonly used up to a sheet thickness of approximately 12.5mm.

However, the ionization potential and thermal conductivity of helium is much higher than for argon. Helium is typically used as an opportunity to produce heat at a higher temperature in MIG aluminum welding.

To work on thicker aluminum, argon can be mixed with helium in an effort to get a higher temperature coupling in the welding process. This mixture could vary anywhere from 25% helium to 75% helium, depending on the type of material being worked on.

Where can you get industrial gases for your Ontario-based business?

Are you looking for industrial gases for your Ontario-based business? Simcoe Gases has your back.

We are the leading independently-owned distributor of industrial and commercial gases in the Simcoe region, Greater Toronto Area and Central Ontario. Conveniently located in Barrie, our team has vast industry inexperience and expert knowledge in all things industrial gas related.

Our extensive range of gases include argon, nitrogen, oxygen, acetylene, propane, helium, as well as speciality gas mixtures. All of which come in a variety of cylinder sizes depending on your specific needs.

Need help finding the perfect industrial gas for your Ontario business? Get in touch with our team today. We would be more than happy to help!


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