What Is the Mix for Shielding Gases?

The most common shielding gas mixture for welding is 75% argon and 25% carbon dioxide (CO2). But there’s more to the story when it comes to effective gas combinations.

In this guide, we explore different shielding gas mixtures to show you some popular options. We’ll then discuss the main factors to consider when finding the right mixture for your welds.

Understanding the Basics of Shielding Gas Mixtures

Shielding gases create an invisible shield around your weld, protecting it from the atmosphere that could otherwise ruin your hard work.

Think of shielding gas as a protective bubble around your weld pool. Without it, oxygen and nitrogen from the air would rush in and cause issues like porosity and excessive spatter.

Different materials and welding processes call for different gas mixtures. Before starting your welding project, you should understand its specifics and find the right mixture for each application.

Further reading: Everything You Need to Know About Shielding Gases

Popular Shielding Gas Combinations and Their Applications

The classic 75/25 argon-CO2 mix is the most popular shielding gas mixture for a few reasons. It offers excellent weld quality while being cost-effective for most general steel welding applications.

For stainless steel, you might want to consider a tri-mix of helium, argon, and CO2. This combination provides better heat control and helps prevent discoloration.

Aluminum welding typically calls for pure argon or an argon-helium mixture. The helium helps increase penetration and welding speed, especially on thicker materials.

Other common mixtures include:

• 90% Argon/10% CO2 for thin material welding
• 98% Argon/2% Oxygen for spray transfer welding
• 85% Argon/15% CO2 for short-circuit transfer

Factors That Influence Gas Mix Selection

Your choice of shielding gas mixture depends on a few factors, with the material you’re welding being the most important consideration.

Other notable factors are:

• Material thickness: thicker materials often benefit from gas mixtures that provide better heat penetration.
• Welding process: MIG welding might require a different mix than TIG welding, even on the same material.
• Cost: While pure argon might give you the best results, a mixture with CO2 could provide acceptable quality at a lower price point.
• Flow rate: the right flow rate is just as important as the right mixture. Too little gas won’t protect your weld properly, while too much is just wasting money.

Choosing the right gas mixture can seem overwhelming. If you need help, work with a supplier who can help you select the right combination for your specific application.

Choose Your Shielding Gas Mixture Wisely

The right shielding gas mixture prevents welding mishaps and makes a world of difference to the end result. It affects everything from arc stability to weld appearance and strength.

There’s no one-size-fits-all solution in welding gas mixtures – but with the right knowledge and support from a reputable supplier, you can find the perfect combination for each project.