Gas Vs Gasless MIG Welder – What Should You Choose?

There’s been quite a debate about Gas Vs Gasless MIG welders. Well, the key difference is that a gas MIG welder use an external shielding gas, while a gasless MIG welder does not. Instead, a gasless MIG welder uses inner shield or flux core wire that has shielding gas characteristics. The shielding gas in MIG welding is used to prevent the welding surface from atmospheric containments, oxidation, and exposure.

If you’re new to MIG welding, we’ve got you covered. My name is Jaxon, an experienced welder, and I’ve been around the welding industry for a while now. Let’s take it from the start and I’ll try my best to answer each possible question about gas and gasless welders.

MIG Welding – An Overview

MIG welding is a globally accepted and well-liked process to ever exist for professional and novice welders. However, it is not a one-size-fits-all process. At times, you need to switch to TIG or stick welding. Similarly, the hype about ‘all around’ MIG welders is real but they are not suitable for all kinds of welding tasks.

We have to make a calculated choice for the type of welding when welding with specific skill-sets in specific environments and not to mention, specific situations.

Types of MIG welders

Yes, MIG welding is not rocket science but that does not mean winging your welder on the metal and expecting good welds right away.

We have to make the right welder choices in MIG welding, execute the right yet tested techniques and use proper tools.

There are two types of MIG welders i.e. gas and gasless MIG welders. The first one goes by the name, gas-shielded welder while the other one goes by name, self-shielded welder.

Is There Gasless MIG Welding?

“Do you need gas for MIG welding?” is probably the most asked question among novice welders.

Well, there’s no such thing as gasless. What people regard as gasless MIG welding could be a little confusing – speaking from an expert point of view.

The weld pool has to be shielded from the oxygen present in the atmosphere. Therefore, the gas comes in place of the atmospheric air. Thus, the reason why professionals call it, gas-shielded welding and not gasless MIG welding.

In simple words, you’ll still be using a gasless MIG wire that has similar properties as that of shielding gas.

Gas Vs. Gasless MIG Welder – How Are They Different?

The main difference between the two types of MIG welders lies in the use of shielding gas. A gas MIG welder requires an external shielding gas for the weld pools while the gasless MIG welder does not require an external shielding gas.

Gasless MIG Welder

A gasless MIG welder uses a self-shielding wire, commonly known as Innershield or flux-cored wires. The wires consist of metallic tubes with flux-core. The wire causes the inside flux to melt and produce a shielding gas whenever it is heated. That is the inside procedure of how a flux-core wire protects the weld from contamination and oxidation.

The flux-core wire helps you MIG weld without gas.

In addition to that, a flux-cored wire also gives off a protective slag to integrate alloys or the base metal into the parent metal.

Self-shielding or gasless MIG welders have other advantages besides protecting the weld pools from contamination and oxidation. For example, they are capable to produce intense arc, which is useful for steel and mild steel thinner than 1.2 mm.

Gas MIG Welder

Shielding gas is an essential component of the traditional MIG welding process because it protects the welded object from oxidation and contamination caused by atmospheric exposure.

While there are multiple ways one can use a shielding gas for a gas-shielded MIG welder, professionals prefer to use gas cylinders to pull the work off.

History Of Self-Shielding (Gasless) MIG Welder

Gasless MIG welders were first developed in the US. They originated from the mid-west region where people used them on vast and widely-spread prairie farms. The use of a gasless MIG welder gave birth to the hand-held gasless MIG welder, which was capable to run on a 24V tractor battery (deep cell). The farmers used to carry the gasless MIG welders with their bare hands alongside their tool kit.

The hand-held gasless MIG welders were, later on, used for repairing metal and steel gates on the farmlands. That’s when gasless MIG welders ended up on the DIY market – in the late 1980s.

History Of Gas MIG Welder

Gas MIG welders were developed in the early 1940s for welding non-ferrous and aluminum materials. The technique was, then, applied to steels and other metals because the process was fast and gave the best results.

Related: 12 Best MIG Welders (Both Gas & Gasless) For The Money 2021

Key Differences Between Gas And Gasless MIG Welders?

Key Differences Between Gas and Gasless MIG Welders

Some of the differences between gas and gasless MIG welders are as follows:

Polarity Change

Another major yet noticeable difference between gas and gasless MIG welders is the polarity settings. A gasless MIG welder uses a negative (-) torch feed while a gas-shielded welder uses a positive (+), single torch feed.

But if you drive the relay of the welder by a trigger, the polarity settings of both types won’t matter at all.

However, some welders come with the polarity change feature. They can do both, gas and gasless MIG welding. The users only have to switch the torch’s polarity settings to switch between gas and gasless MIG welding. However, the need for polarity change must strictly depend on the type of welding job.

MIG welders with gas and gasless welding option are quite expensive. Moreover, you must upgrade your welding kit to use the ‘gas’ application in the welder.


The amount of smoke and fumes produced by both types of MIG welders are different. While a gas-shielded MIG welder produced little to no fumes and smoke, a gasless MIG welder produced excess fumes and smoke.

The fumes and smoke produced by a gasless MIG welder are quite toxic and harmful to human health. Direct exposure to gasless welding fumes and smoke might cause short-term ailments such as nausea and dizziness. On the other hand, the long-term effects of smoke exposure might make you prone to cancer.

Therefore, gasless MIG welder should only be used outdoors, in a well-ventilated and airy area.

Outdoor And Indoor Suitability

The flux-core in the Innershield wires in gasless MIG welder produces a protective slag (kind of a vapor) during welding. Therefore, they are suitable for outdoor ventilated areas where the weld pools are not vulnerable to wind and environmental contamination. Exposure to atmospheric contamination might produce low-quality and weak welds.

Whereas, gas-shielded MIG welders are suitable for indoor areas where there’s not a peck of wind or contamination. The shielding gas works as a protective compound for the weld pools but it is highly vulnerable to contamination from drafts and outdoor elements such as the wind.

Metal Preparation

You must clean the metal from debris, rust, paint, and dust before using a gas-shielded MIG welder on it. However, the case is quite different for a gasless MIG welder. It uses flux-core wires which enable welding on materials that are contaminated with debris, dust, rust, and paint.

Therefore, the metal preparation and cleaning time for gasless MIG welding is quite less as compared to gas-shielded MIG welding.

However, I recommend cleaning every metal before MIG welding as it makes the process quick and convenient.

Welding Capabilities Of Gas And Gasless MIG Welder

The welding process is not different but rather the thickness and type of metal that you can weld with both types of MIG welders.

Gas-shielded MIG welders are capable to weld:

  • Aluminum, mild steel, and stainless steel
  • Smooth and clean metals
  • Metals with thickness up to ½ inch but less than 1/16 inch (24-gauge)

Related: Best MIG Welders For Aluminum

On the other hand, gasless MIG welders are capable to weld:

  • Mild and stainless steel
  • Dirty and textured metals with debris, dust, rust, and paint
  • Metals with thickness less than 1 inch (20 gauge)
Gas Vs Gasless MIG Welder Metal Capabilities

Gas-shielded MIG welders can weld up to metals with thickness up to ¼ inch and are popular for welding a variety of metals. Whereas, gasless MIG welders are popular for deep weld penetration. Therefore, they are used to weld thick metals.

It is recommended to use gasless MIG welders for thicker materials otherwise your welder may start popping or producing more spatter.

Clean Up And Appearance

The gas MIG welders produce neat and nice welds. Also, they do not require shipping or sanding and produce less spatter (sputtering). It reduces the amount of clean-up for a welder and enhances the appearance of the welds.

However, gasless MIG welders produce more slag and spatter which increases the clean-up time for a welder.

Pros And Cons Of Gas And Gasless MIG Welders

Now that you know all the similarities and differences of the oh-so-famous welders, let’s get to the ups and downs.

Pros Of Gasless MIG Welder

The advantages of using a gasless MIG welder are:


A gasless MIG welder wins over a gas-shielded MIG welder in terms of convenience. Self-shielding MIG welders are compact and lightweight. They are easy to carry with your toolkit.

Moreover, flux-core welding is suitable for rusted, painted, or contaminated metal surfaces. The flux-core wires weld through the debris, dust, paint, and rust.

Good For Outdoor Areas

Gasless weld works best in outdoor areas.

If a large chunk of your welding jobs requires you to work outside, consider investing in a gasless MIG welder. Gas welders lose their gas in windy areas. This increases the porosity and decreases the quality of the welds. However, self-shielding welders can work with contaminants and other outside elements such as drafts and wind.

The Arc Control Is Efficient

The efficient arc control in gasless MIG welder allows for precise, smooth, and clean welds. However, you have to pair the welders with wire feeders (voltage-sensing).

Cons Of Gasless MIG Welder

  • High production of fumes
  • Gasless MIG weld produce more spatter
  • Limited positioning

Pros And Cons Of Gas-Shielded MIG Welder

Gas-shielded welders provide a host of ways to make welding easier for novice welders. However, it has its share of pros and cons. Let’s dive into them:

Pros Of Gas-Shielded MIG Welder

Some of the pros are as follows: 

Gas MIG Welders Comply With Welding Codes

You don’t have to worry about the structural welding codes for gas-shielded MIG welders. Unlike gasless MIG welders, you don’t have to keep an eye on the codes laid out by the D1 committee of the American Welding Society.

Less Spatter

The gas-shielded welders are used indoors and on clean metals. That is why these welders produce less spatter. You would have strong and high-quality welds with a smooth bead appearance. Moreover, the clean-up time is less as compared to gasless MIG welders as little to no spatter is produced during the process.

Flexible Positioning

Unlike gasless MIG welders, you are not relegated or restricted to limited positions while welding. It is best if you have a welding job that requires vertical or overhead positioning for welding.

No Production Of Fumes

Gas-shielded welders have flux coating which allows the welding object to melt faster and create strong bonds with little to no smoke and fumes. Moreover, the flux covering holds the weld pools and makes it easier to continue vertical or overhead welding.

Unlike gas-shielded MIG welders, the fumes and smoke escape from gasless welders and compromise your health.

If you are health conscious and don’t want short-term exposure to toxic chemicals that cause dizziness or nausea, switch to a gas MIG welder right now!

Cons Of Gas-Shielded MIG Welders

Portability is a problematic occurrence as you have to carry the gas cylinder too

  • Loss of gas due to outside elements, such as wind
  • Frequent replacement of consumables

Final Verdict

There’s no gasless MIG welder that could perform all kinds of welding jobs. Similarly, no gas-shielded MIG welder could work for jobs where you need deep weld penetration. The choice of the type of MIG welder depends on the situation, the environment, and the specifics of the welding job.

Learn more about MIG welding and find yourself the best MIG machine for your welding projects at

In case of any questions or suggestions, don’t hesitate to leave a reply.

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