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Shielding Gas Basics for MIG Welding

If you’re taking up MIG welding, there are a few things you should know, including the types of gases you can use. MIG welding, which stands for metal inert gas welding, works by consuming the electrode wire, which is fed to the arc zone from the spool.

Choosing the correct gases and their quantities is essential when welding, so in this blog, we’ll look at some of the basics for MIG welding, including shielding gases and their uses.

What Are Shielding Gases?

Simply put, shielding gases have a very distinct purpose in MIG welding. They protect the weld area from oxygen, water vapour, nitrogen and hydrogen. Without this protection, the welding is not done correctly and can lead to several problems, including holes in the weld.

There are many different shielding gases, but the most commonly used ones are:

  • Argon
  • Helium
  • Carbon Dioxide
  • Oxygen

We’re well-established suppliers of MIG welding gas across the UK, so don’t hesitate to speak to us today if you’d like to learn more about our products.

Choosing the Right Gas

It won’t do to pick a random gas and hope for the best – you must choose the right one for the application at hand since each gas has unique benefits and drawbacks depending on how and where they’re used.


Argon is a noble gas with the symbol Ar and the atomic number 18. Depending on what you’re looking to achieve, you can use it alone or mixed with other gases – mixtures can create better arc stability or reduce spatter and lead to more attractive welds.

If you want to weld materials like stainless steel or carbon steel, a mix of argon with CO2 can be the better option, though it’s important to balance the quantity of gases because too much carbon dioxide can lead to more spatter – this refers to the drops of molten metal produced near the welding arc.

Argon is also an excellent choice for butt and fillet welds and can be used to weld non-ferrous metals in its pure state. This means that choosing the right gas will also depend on the materials and metals you’re working with. Argon is, therefore, a great choice if you’re welding metals like aluminium or copper.


In the periodic table, helium has the symbol He and the atomic number 2. This gas is often used for non-ferrous metals as well, and it offers a great performance if you’re working with thick metals. Helium produces a hotter arc than other gases, which increases your welding speed.

It can be used together with carbon dioxide and argon when welding stainless steel, and you can also use it to prevent oxidation.
The downside of using helium is that it’s a costlier gas, as it’s a non-renewable resource that’s slowly disappearing. It also has a higher flow rate than gases like argon.

Carbon Dioxide

You’ll want to choose CO2 when you have a stricter budget and want the cheaper option. This is because carbon dioxide is the most reactive of all these shielding gases and doesn’t require the addition of an inert gas, so it’s not a surprise that this is such a popular option for both beginners and professional welders.
Carbon dioxide gas is also great for thick metals, so you can use it for a wide range of applications.

The cons of choosing CO2 is that the arc it produces is not as stable as the one created by other gases, such as argon and helium. Additionally, it can also create more spatter, so you may want to mix it to prevent this.

Also, it’s worth keeping in mind that if aesthetics is not as important in your project, then this gas is a good choice. However, if you want the weld to be visible and, therefore, as ‘perfect’ as possible, you may want to mix it with other gases.


This is also a reactive gas. Oxygen has the symbol O and the atomic number 8, and is used in small quantities when mixed with other gases (around 9% or less). Adding oxygen ensures arc stability and helps it penetrate materials like stainless steel better.

However, oxygen should be avoided if you’re working with metals like aluminium and copper, since it can lead to oxidation.

This gas is also used in oxyacetylene welding, which uses both oxygen and acetylene to produce flames with temperatures of around 3,200oC.

Adams Gas Can Help

In short, shielding gases are all different and better for certain applications, from non-ferrous metals to more attractive welds. After all, shielding gases impact the weld penetration, the stability of the arc, the quality of the finished weld, the properties of the weld, and more, so you’ll need the right gas for your project.

We have everything you could possibly want at Adams Gas, from pure gases to mixes, so browse our website to see them for yourself. And, if you have any questions about the products we stock (not just our MIG gases, but supplies like TIG welding gas or beer gas), don’t hesitate to reach out to our friendly team, who will be more than happy to advise you further.


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