Welders Galore

Welders Galore

Gas vs Gasless MIG Welding: How to know Which to Use?

Many people that are new to welding appreciate MIG (Metal Inert Gas) welding because it can create neat and strong joints. This welding process uses an inert gas to shield the welds from contaminants that can compromise the strength and quality. It is possible to use a gasless approach using flux cored self-shielded wire that creates the gas. In this article, we will take a closer look at gas vs gasless MIG welding.

Understanding the Role of Gas in Welding:

The main advantage of MIG gas vs gasless welding processes is that the weld pool is shielded from oxygen. The oxygen in the atmosphere can compromise the weld quality, and there are industrial grade gases that can protect against other contaminants too. These gases are referred to as shielding gases because they shield the molten weld pool against interactions with airborne gases.

The Functions of Shielding Gases

gas vs gasless mig welding
  • Improved arc stability
  • Formation of plasma
  • stabilized art toots on surfaces
  • Assisting the transfer of metal.

MIG gas welding makes the transfer of the molten droplets from the wire to the welding pool smoother. There are a number of welding gases on the market and special gases that can be used in MIG welding processes. The shielding gas that you choose will depend on the demands of the material, the desired welding arc characteristics, and the required depth of metal penetration.

As you can see, in this comparison, gas vs gasless MIG welding relies on shielding gas.

What is Gasless Welding?

This process is not truly gasless because the MIG welder uses a fluxed cored wire. This wire creates a “self-shielding” gas when the welding arc melts the wire. So, gas is present to protect the weld, but an external gas cylinder is not needed for this process. This is an attractive prospect for hobby welders, but gas is better for industrial use.

Is MIG Welding Better with Gas? 

Yes, MIG welding is preferable to gasless because it’s less expensive and it produces fewer toxic fumes. MIG welding does produce some toxicity, but the smoke and fumes are reduced when compared to self-shielding gas produced by melting wire.

Gas vs Gasless Mig Welding: Differences:

There are five main differences when a MIG gas vs gasless approach is under consideration:

1.    Ease of Use When Welding

Gasless MIG welding is not a precise option unless you’re working with thick and mild steel. Gas MIG welding is a more flexible and precise process which makes it an ideal choice for any size of metal block or plate.

2.    Push or Pull? Gas vs Gasless MIG Welding

During gasless MIG welding, the rod is pulled to create the required drag to make the weld. The welding machine’s polarity is always negative when self-shielding gas is used. During the gas MIG welding process, the rod is pushed to create the weld. The welder polarity is always positive until the weld is completed.

3.    Gas vs Gasless MIG Welding Toxicity

We touched on this earlier, but gasless MIG welding does create a large volume of toxic smoke, and a good respirator is a must. During gas MIG welding, the smoke and fumes are noticeably reduced but wearing a respirator is still advisable.

4.    Transportability of the MIG welder

It’s easy to move and maneuver a gasless MIG welding machine because it’s less bulky. There is no need for a gas cylinder and this significantly improves the portability.

5.    Welding in Windy Conditions

gasless MIG as good as gas MIG

This is one of the few applications where a gasless MIG welding approach is superior. Welding outdoors can be a real challenge because the wind can blow the shielding gas away from the weld pool. This increases the chances of contamination when gas MIG welding is outdoors. But, gasless welding directs the gas closer to the weld pool, and this reduces contamination.

Pros and Cons of MIG Welding Without Gas:


  • Welding without gas is ideal for outdoor work.
  • Using a flux cored rod is easier to learn and master.
  • No gas bottle is required, which improves portability.
  • This welding process can be forgiving if the material is not prepped perfectly.


  • Gasless MIG welding indoors produces a lot of smoke and toxic fumes.
  • There are materials that cannot be welded with gasless welding.
  • The MIG welder that you choose must support gasless welding.
  • Flux core wire is easily damaged if it’s not handled carefully.

FAQs- Gas vs Gasless MIG Welding

Can you weld thin metal with a gasless MIG welder?

Gas MIG welding is preferable if you’re welding metal with a thickness less than 1.2 mm and if you use 0.8 mm flux cored wire. Gasless MIG welding can produce acceptable welds when the metal is thicker because the welding arc is intense. If you have a MIG welding machine that supports gasless welding and 0.9 mm wire, it is possible to weld 20 gauge mild sheet steel from 1/16” up to ½” thick.

Is gasless MIG as good as gas MIG?

No, even if you have a MIG welding machine that supports gasless welding, you should use it with gas. The only exceptions should be applications where you need to use a self-shielded flux wire, such as: outdoors when it’s windy.

Why do you need gas for MIG welding? 

The shielding gas protects the molten weld pool from atmospheric elements that can cause a reaction that degrades the quality of the weld. Low quality weld joints reduce productivity and efficiency when they are repeated.

What happens if you MIG without gas?

The term “Gasless” is a convenience; in reality, a self-shielding flux core wire is used. This wire melts as it comes into contact with the welding arc, and this burns the flux to produce a precise shielding gas. When a welder talks about gasless welding, they are referring to welding that doesn’t use a gas cylinder.

How do you weld with a gasless MIG welder?

A MIG welding machine may be designed to use gas, gasless, or both methods. The main difference is the polarity of the torch, which must be negative for gasless and positive for gas. A machine that can use both MIG gas and gasless processes will have a control to change the polarity quickly. A MIG welder that can operate with gas and gasless methods is typically marketed as a “Gas/No Gas MIG Welder”.

Conclusion-Gas vs Gasless MIG Welding

We hope that we have shed some light on the gas vs gasless MIG welding differences. To summarize, gas MIG welding is almost always the best option unless you’re working outdoors in high winds. Ultimately, the metal type, thickness, and specific application will be the determining factors when you want to make high-quality welds efficiently.

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