What’s the Best Gas for MIG Welding – A Complete Guide

Last Updated on January 5, 2022 by Luis Ferency

Typically MIG welding utilizes the hand-held gun along with a spool-fed cable of the electrode and a gas nozzle which is responsible for releasing the stream of gas into the welding site. The gas works as a protective, shielding agent that can help in preventing any contamination to enter into the weld. Furthermore, the gas takes charge of stopping oxygen and nitrogen contract as well as other ambient gas within the weld bead. As the welder does not compromise on the final results, hence it makes sure that the gas provides a strong and consistent controlled flow.

Every welder is familiar with the side effects and quality produced due to the contamination. Thus, he knows the benefits of choosing the best gas suitable for each material. Hence, if you are into the curiosity of getting the same awesome results as professional welders, you must also take the welding gas part more seriously.

So let’s spend some more time understanding what is the best gas for MIG welding? Getting an answer to this simple and straightforward question cannot be comprehended in one sentence. Therefore, you need to spare time and learn the key aspects that make a gas suitable for MIG welding.

Many different metals require types of gases that hold distinct features to get the best results. Moreover, in various instances, the mixture of 75% carbon dioxide with 25% of argon gas can provide excellent finish results on the metals.

Hence, today we will evaluate the MIG welding gases and discuss how one can choose the gas for their undertaking. Enjoy your readings.

Types of Gases in Welding

Generally, the MIG welding can be taken place with an arc spawned through a constant solid wire electrode. Thus, these electrodes then pass with the help of a welding gun and produce a weld pool on the upper surface of the point that connects the base metals.

Typically, the arc is being guarded by a shielding gas which is responsible to pass through a MIG welding gun. Also, this shielding gas is designed to protect the weld pool from pollution and any type of contamination. To perform the shielding task, different types of gases have been used which safeguard the weld from any type of environmental pollution.

These gases then further subcategories into inert gases and non-inert gases.

Inert Gases or Noble Gases:

Usually, inert gases or noble gases have a tendency to understand the environmental condition, sustain within it, and are highly resistant to chemical changes. This gas can imply as the shielding for weld and during arc to get high-quality protection. The most common inert gases are helium and argon gases. Moreover, you can find the great usage of these two gases in MIG and TIG welding.

There are some newbies out there interested in getting full information regarding gases. Are they even curious to ask questions from a basic level such as Can we weld mild steel using argon? To advance level. This makes them learn more about welding gases. By the way, the answer to mild steel using argon is “yes, you can weld it”.

In addition to carbon dioxide, the next top-most and common shielding gas used while doing a welding job is argon. Thus, the welder can use the argon gas on its own, so it’s up to the welder to either use 100% gas or to allow the more deep penetration in the metal you can make a combination with other one or two gases.

Though argon gas is great as it assured the broader perspective when shielding the metal but it doesn’t penetrate too deep weld. However, it is an excellent choice to maintain an arc at a stable angle. On the other hand, when compared to helium, it produces hotter burns over argon and can create more deep welds. Though the cost of helium is quite high as compared with argon.

Interestingly, the noble gases are amazing at forming less spatter especially when welding. This is due to their tendency to high resistance to chemical reactions than non-inert or semi-inert gases. Moreover, an inert gas such as helium significantly lessens the porosity of the weld.

However, the amount of power utilized by helium is relatively high than argon. Hence, it requires much care as it gets sultry over time. Moreover, it is important to cool down as it can cause burnout and overheating.

So to overcome such issues, many welders combine both argon and helium gases with less costly gases. This helps the welders to cut off the price issue. Also, these gases helium and argon should purely use when you are working on non-ferrous metals such as aluminum and copper. Moreover, mixing the gases have their benefits and is quite important.

Selection of a suitable shielding gas:

There are numerous applications of MIG welding that can offer different variety of options for shielding gas. All you have to do is to pick up the right shielding gas option for your particular application after properly assessing the welding applications and your welding objectives.

Since welding gases play a critical role in performing any welding task. These gases are responsible to protect the weld by preventing any type of atmospheric gases for instance hydrogen, nitrogen, and oxygen to get into the weld pool. Because these atmospheric gases can be a problem that can create major issues on the quality of the finished weld. So, the moment they get into the weld pool the weld will be contaminated and can produce poor results. Therefore, having a shielding gas is a must.

Regardless of the importance of having the shielding gas, people are still not clear on which shielding gas they should use for their welding project? With the four top-most commonly used gases Argon, oxygen-carbon dioxide, and helium, and their combinations or from a variety of other available options, you have to pick something that satisfies your need. As each of these gases can provide unparalleled pros and cons when you use it in any application.

To make things quite easy for you, we design this comprehensive guide. We suggest you take an account of this summary as it can help you finalize your selection with the best gas for MIG welding.

• Cost of the gas
• Characteristics of the finished weld
• Welding preparation and after cleaning
• The parent/base metal
• Productivity objectives

The cost of the gas:

The crucial and primary consideration of any gas selection depends upon price. The cost of gases varies, some cost high than the others and some are low. Among all the four common gases used during MIG welding, the most affordable gas is carbon dioxide.

So you can either use it pure without using any type of secondary gas to stay budget-friendly. Or you can use it by mixing and making a good combination with expensive gases to balance the overall cost.

Characteristics of the finished weld:

During the weld, several parts require fine finishing. Few of them can be cleaned up afterward while some demands special finishing as a primary requirement. Using argon gas or the mixture of argon-carbon can turn into a great option for those who want good welding actions, fewer spatters, and flatter bed profiles.

Since argon is one of the noble gas therefore it will not react to molten weld. Though, this is a costly gas. So many welders mix it with carbon dioxide and can reduce the cost without compromising much on weld quality.

Welding preparation and after cleaning

If you are conscious about the preparation of welding and afterward cleaning then have argon and carbon dioxide and you will not regret it later. These gases turn to be your best choices that satisfy the welder by offering excellent puddle regulation, arc stability, and lessened spatter when compared with other gases or pure carbon dioxide.

The parent/base material

Typically, carbon dioxide and helium are the gases that are offering broad and deep welds, therefore these gases become an ideal choice when dealing with thick base materials. Unadulterated argon gas is recommended for non-ferrous metals likewise aluminum, magnesium, and titanium.

One can use helium gas for these non-ferrous metals as well as for stainless steel too. Oxygen on the other side works amazingly with stainless steel, mild carbon, and low alloy. Though oxygen leads to corrosion, hence, we cannot use them with magnesium, aluminum, copper, or any other exotic metals

Productivity objectives:

The combined mixture of carbon dioxide and argon gas works amazingly during the procedure of spray transfer. This helps in enhancing productivity. The next recommended combination of argon gas is helium. This mixture holds speed as a key factor. Hence, it creates a hot arc which then further quickly spreads and increases productivity.

Commonly used gases in MIG Welding and benefits of their combinations

1. Argon:

The mixture of argon (75 to 95%) with carbon dioxide 5 to 25% will be a great choice to produce a firm and more quality weld. This mixture can be very helpful in generating a high productivity rate and bring more visual attraction to weld.

Typically argon gas offers a narrower penetration profile which is quite helpful for welding fillet and butt welds. You should use 100% argon while welding non-ferrous metals as base material such as aluminum, titanium, and magnesium.

Properties of Argon:

• Not suitable for steel
• Best gas when using non-ferrous metals for welding

2. CO₂ (carbon dioxide)

The most common reactive gas in MIG welding is CO₂. This is the only gas that can be used safely with its purest form without the urge of mixing with any other inert gas. CO₂ is also one of the budget-friendly gas, thus anyone can afford this shielding gas without pressure on the pocket. Hence you can use it when you can negotiate on the price of gas and make the material cost a top-notch priority.

The purest CO₂ can provide significantly deepest weld penetration that is helpful when you want to weld a wide variety of metals. Though, the drawback of this gas is when mixed with other gases provides a less steady arc and a great amount of spatters. Also, the gas is restricted to procedures that are only short in the circuit.

Properties of carbon dioxide:

• The penetration of CO₂ is deeper.
• The gas produces a large amount of spatter.
• Cheap, inexpensive, and budget-friendly.
• You can only use it with thick metal.

3. Oxygen

This reactive gas can only be used in a very less ratio i.e. 9% or less to give enhancement in weld pool fluidity, in mild carbon arc stability, stainless steel, penetration, and low alloy. Though the increase in fluidity produces in the weld pool can lead to out-of-position problems in welding.

However, the biggest drawback of using this gas is the corrosion of the welding metal. Hence, it is suggested that one shouldn’t use this gas with metals such as aluminum, magnesium, copper, or any type of exotic one.

The welder cannot use pure oxygen gas as a bare one. So, to improve the quality of the weld you can either add it with carbon dioxide or argon with the mix amount of 1 to 5%

Properties of Oxygen:

• You cannot use it alone
• Very less amount gas is used for enhancement of weld
• If uses bare it can causes corrosion

4. Helium

Parallel to pure argon gas, helium is also commonly used for non-ferrous metals along with stainless steel. Since this gas is responsible to produce greater deep and broader penetration profile, this gas can also perform great when you are dealing with thick metals. Typically, one can use this gas with the ratio of (25 – 75%) helium to (75 – 25%) argon.

The adjustment of the travel speed, penetration, bead profile, and these ratios can be changed. Helium gas generates a hotter arc which enables a high production rate and fast travel speed.

When compared to argon, this gas is quite the costliest and requires a high rate of flow. So you have to calculate the increased gas cost with the increase of productivity value. Hence, helium gas is most commonly used when it comes to weld stainless steel with the tri-combination of argon and carbon dioxide.

Properties of Helium:

• Not used commonly
• It is considered to be the best for non-ferrous metals.
• Suitable for thick base metals

Pros and cons of Argon-Carbon Dioxide Mixture for shielding:

The mixture of these two gases comes with pros and cons. Therefore, it is suggested to use them when the welder relies on a specific welding purpose.

Pros of Argon-Carbon Dioxide Mixture for shielding:

• If you are mixing a higher amount of argon shielding gas then you will get better quality in your welding projects.
• The ratio of 75 and 25% provides fast working and result in a much smoother and cleaner appearance of the overall project. The preferred mixture is recommended for fragile projects that require thinner welds or the metals that are placed on the top surface of the structure.
• Welder increases the mixing ratio up to 85%-25% which at the end provides remarkable sleeker bead finish results.

Cons of Argon-Carbon Dioxide Mixture for shielding:

• The mixture where you use most argon gas and less carbon dioxide will cost you a lot. So play smartly and charge according to the cost and your service.
• The high concentration of argon gas reduces the amount of arc penetration. This is the reason where welders don’t prefer to use unadulterated argon gas for their welding. Also, shielding gases that include the Nobel gas i.e. argon are not for mild steel MIG welding, as they lead to creating an inconsistent, ugly weld seam.

Benefits of using 100% Carbon Dioxide for Shielding

• If you want cost-efficient and want your welds to compromise slightly on the appearance then you can switch to carbon dioxide for mild steel MIG welding. This gas is significantly inexpensive when compared with the argon combination mixture.
• Easily supplied and available to retailer stores.
• Not a noble gas like argon but offer significant chemical protection that is normally used as shielding gas for doing MIG welding.
• As compared to the 25% mixture of carbon dioxide with argon, the pure 100% carbon dioxide gas when reacting with the arc produces a “hotter” feeling.
• The gas creates a deep penetration between connecting metals and produces a large and stronger bead.
• The electric arc is not steady during pure carbon dioxide.
• 100% carbon dioxide makes the arc crackle and it pops more. Thus, forms a large amount of spatter.
• It also produces a mild quantity of fume and smoke while welding.
• With higher spatter the much need of cleaning will be needed after the work has been finished.
• Don’t use pure carbon dioxide if your current project is dealing with thinner metal gauges with low Amps. As doing this, the arc can blow a hole into the frame.

Conclusion –choosing that works best for you:

If you are looking for the best options for MIG welding gases that can eventually work amazing on the broader applications that we suggest you go with some mixing. The mix combination of carbon dioxide and argon as 25 and 75% respectively or any other combination similar to this for instance 80 and 20 % respectively are lies under best choices and will surely give you the best results.

Moreover, if you are on a tight budget and can negotiate on cleaning up some tinny additional spatters then go for an inexpensive option such as carbon dioxide without compromising much on the quality. You can also use co₂ for your learning and experimental phase especially when you are a beginner or a hobbyist.

The expensive and long-lasting is argon and typically 100% argon is used to weld thin delicate metals such as aluminum in both MIG and TIG welding. Furthermore, things become more costly especially when dealing with stainless steel metal. Here the helium is mixed with either argon, oxygen, or co_2. Moreover, for low quality and reasonably low priced products, some welder uses co₂ with the mix of up to 98 and 2 %.

Hence, while welding we suggest you take an account of the metals and their properties that you will be going to weld. Meanwhile, you are welding, it is important to get the most out of your welding gas flow. Always remember that the primary factor to a dependable bead pattern lies under the gas flow rate and by avoiding the metal of your preferred gas.

Another pro tip while setting up the gas flow, it is important to contact the machine’s manufacturer and ask them to see what can goes best for you and the one which will work conveniently.

FAQs:

1. What is the best gas for MIG welding mild steel?

Argon gas is the best MIG welding for mild steel. With the mixture of argon (75 to 95%) with carbon dioxide 5 to 25% work as the best all-purpose shielding gas to produce a firm and more quality weld for carbon weld.

2. What kind of gas does a welder commonly used for MIG welding?

The most common reactive gas in MIG welding is Carbon dioxide. This is the safest gas and can be used in its purest form without the urge of mixing with any other inert gas. Also, CO₂ is budget-friendly gas, so anyone can afford this shielding gas.

3. Can I use the same gas for MIG and TIG?

You cannot use the same gas for MIG and TIG welding. It is because TIG welding mainly needs inert gas to create a clean finish with no oxidation.

4. What shielding gas is used for MIG welding stainless steel?

Take a guide to understand the metal and recommended gas used as MIG shielding gas along with its effects on the thickness

Metal	Thickness in. (mm)	Recommended Shielding Gas
Stainless Steel	All thicknesses	99% Argon / 1% O2 or 98% Argon / 2% O2
Copper, Nickel & Copper-Nickel alloys	Up to 1/8 (3.2)	Argon
	Over 1/8 (3.2)	Argon – Helium