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Since MIG stands for Metal Inert Gas, it goes without saying that gas is an essential element for MIG welding. However, gas is not compulsory for beginners.
There are many reasons why you might have decided to try out welding. Perhaps you consider it as a hobby or even a career. If you are wondering if you need gas for MIG welding, it is probably because you want a good weld. We understand your thoughts.
What Is MIG Welding?
This is a subsidiary of a broader type of welding called arc welding. It involves using a high voltage of electricity to generate enough heat to melt metals. As the metal cools, the joints get fused. MIG welding entails using a solid electrode alongside some kind of inert gases to melt the electrode and fuse joints.
MIG welding has gained popularity among welders over time as it gives a clean finish after mild steel welding. It has been seen as an easy DIY MIG welding option by farmers, motorsports devotees, and artisans. It allows them to carry out very different kinds of constructions and repairs without stress.
Does Gasless MIG Welding Exit?
Gasless MIG welding does not exist. Consequently, displacing the air with shielding gas is how a welder can protect the weld pool from the oxides in the air. Self Shielding MIG wire uses what is known as flux core wire (also known as flux core welding). By melting the flux core wire and burning the flux simultaneously, the welding arc produces a gas shield around the weld which therefore is not gasless in the strictest sense of the word.
What Gas Do You Use For MIG Welding?
We have established that if you want to get the best out of your MIG weld, it would require that you use gas. It serves as a kind of shielding gas for the welding area from external influences that might mess with the quality of your work.
To Identify the suitable gas to use, you could:
- Consult the manual of your MIG welding machine
- Go through the instructions on your welding wire, as different wires have peculiar requirements
- Consult the store where you purchased the particular machine
In the next section, we shall identify and explain common gases used by your MIG welder.
Common Gases Used In MIG Welding
Common gases employed in MIG welding include carbon dioxide, helium, argon, and oxygen. Every gas hones unique advantages and disadvantages when applied when using your MIG welder for different materials. We shall proceed to identify and explain some gases used in MIG welding.
This is the most common and most abundant gas employed in MIG welding, and you can use it directly without adding an inert gas. It is considered the cheapest also; hence it is the first choice when costs are a priority.
Carbon dioxide gives a deep penetration when used in its pure form in welding, making it fit for joining thick materials. The gas, however, is considered to form a less stable arc compared to when it is mixed with other gases. The application of carbon dioxide when using a MIG welder is limited to just short circuit processes. Combining carbon dioxide with the percentage of argon will improve the quality of the joint and the look, bringing after-weld cleaning to the barest minimum.
Such a mixture can also blend a stable arc with decreased spatters than pure carbon dioxide. Mixing carbon dioxide with argon also gives welds that are more attractive and provide a maximum productivity rate.
It is a standard inert gas employed in MIG welding. Argon produces a relatively narrow stream compared to other gases, and it ensures a much cleaner weld. It is just like trying to make a straight line on a surface with a pencil. Using a thinner pencil and ruler would prove more effective in getting the job done than using a fatter pencil. The same applies to using argon. Argon is a go-to gas when MIG welding is considered, as it is an inert gas, other gases that might be as effective are not inert gasses and hence cannot be employed in MIG welding.
Usually, welding machine manufacturer manuals come with charts that specify the best kind of gases to use and a guide on the makeup of the metal being welded and the type of wire to use.
Using argon by itself, however, is not advised. Nevertheless, when welding non-ferrous metals, aluminum, magnesium, or titanium, you must use 100% argon.
Compared to pure argon, helium is mainly utilized in welding non-ferrous metals and stainless steel. As it offers a broad and deep penetration characteristic, helium is effective in thick materials and is generally used in proportions between 25% and 75% helium and 75% to 25% argon. Adjusting the conditions changes the penetration depth and travel speed. Helium generates a hotter arc that permits higher travel speeds and increased productivity.
Helium gas is, however, on the high side and needs an increased flow rate compared to argon. For stainless steel, helium is typically used in a mixture of argon and carbon dioxide.
Oxygen is a highly reactive gas commonly used in amounts of 9% or less to improve weld pool fluidity and the stability of arcs in soft carbon, penetration, stainless steel, and low alloy steel. This method, however, leads to corrosion of the molten metal. It is not advisable to use it with magnesium, aluminum, copper, or other exotic metals.
Oxygen should not be used for welding alone; however, it can be used alongside a mix of 1% to 5% argon and carbon dioxide. It helps to improve the quality of welding.
Oxygen and argon are mainly used to transfer by spraying onto stainless steel to create a stable arc. The increase in the fluidity of the MIG weld pool can make welding in the wrong position problematic.
Hydrogen is another gas that can be used in your MIG welder. Hydrogen is used as a shielding gas in high-temperature applications such as stainless steel. It is usually mixed with argon for use on austenitic stainless steel.
Nitrogen is used as a vent gas for welding stainless steel pipes. Argon added in small amounts can also be used as a shielding gas for stainless steel.
Propane is most often used to cut carbon steel at scrap yards where the quality of the cut is not essential. If the application does not demand a high-quality cut, propane is a relatively inexpensive alternative.
What Is The Best Gas For MIG Welding?
Choosing the best gas for MIG welding is all dependent on the kind of material to be welded. Helium, oxygen, carbon dioxide, argon, hydrogen, nitrogen, and propane are all gases utilized in MIG welding. However, when picking the appropriate gas, specific points must be put into consideration.
What To Consider Before Choosing The Best Gas For MIG Welding
Cost is a critical factor in all production processes. Some gases are more expensive than others. Carbon dioxide is the cheapest gas of the gases used in MIG welding. You can use it in its pure form and therefore do not need secondary gas. It helps you save more.
The Characteristics Of The Material
Various pieces need to be well finished to give an aesthetic appeal. Others can be cleaned up afterward, while they may have no special finish requirements. Argon or the argon-carbon dioxide mixture is the best choice for minimizing spatter, increasing welding performance, or flattering bed profiles. Argon is an inert gas and does not react with molten welds, but it is on the high side. Using a mixture of carbon dioxide and argon can reduce costs while still providing an excellent weld quality.
The Productivity Needs
Argon and carbon dioxide mixed is just right in the spray transfer process, which increases productivity. The argon and helium mixture is another typical mix. Speed is a factor that is highly regarded in this mix. It generates a hotter arc that spreads fast and brings about higher rates of productivity.
On A Final Note
MIG welding can be your best welding process if you know the right combination of gases. It is also the most straightforward welding process to learn and master. However, if you are planning to buy your MIG welder for the first time, choose one with a gas mixture diagram so you know what kind of metal you can use your MIG welder effectively. Or, if you are buying from an actual store, you can ask the store staff to recommend the right combination of gases for your metals, including the correct wire size, electrode type, and polarity.
Using different gases for welding can help you with your projects, regardless of the type of metal being welded. Carbon dioxide is the most helpful gas in MIG welding. If you have to weld thin metals with MIG, you must learn the correct mixture of carbon dioxide with inert gases; otherwise, you have to go for a TIG welding machine.
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