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Flux Core vs. MIG Welding: What Is the Difference?

Flux Core vs. MIG Welding: What Is the Difference?

There are a few different types of welding methods out there and many people may debate over which is the best. Two of the most commonly utilized types of welding are MIG and Flux Core. Realistically, both of these are valid methods and they both have their advantages and disadvantages. If a person is new to welding, it can be difficult to know which method they should begin learning or which would be more appropriate for them. Let’s take a look at the various factors that can help you decide, starting with a comparison of these two methods. 

The Wire Involved in Flux Core Welding and MIG Welding

First and foremost, both of these methods use a spool of wire to provide the filler metal to the weld, but the primary difference is in the type of wire. MIG welding uses a solid wire, whereas flux core welding wire is tubular and inside the tube is flux, hence the name. There is  a significance behind the flux, which is also where a large difference arises between these two methods. 

Air Protection Method

When a weld is being done, the hot metal cannot contact normal air, as it can cause a bad weld. To do this with MIG welding, a shielding gas is used. This means that there will be a tank of shielding gas hooked up to the MIG welder that will dispense the gas to protect the weld. There are a few different gases that may be used for MIG welding, which would be argon, argon and carbon dioxide mix, carbon dioxide, or tri-mix, which contains all three of the above gases. Tri-mix is mostly used for stainless steel welding. 

As for flux core, this is where the core of the wire mentioned above is important. When flux core wire is being used, the flux in the center heats up and releases gas, which provides the protection from the outside air. This means that it does not require a separate tank of gas to weld, which often makes this a more popular method of welding. Although, there is also a form of flux core welding that uses something called double shielded flux core wire, which does require a tank of gas. 

Strength of the Weld

Welders will debate whether flux core welding or MIG welding provides a stronger weld until the end of time. The truth of it is that they are ultimately pretty similar. For most applications, both methods will provide a strong weld that will hold what it needs to. Both wires fit the standards of the American Welding Society, which means that they will provide a tensile strength of at least 70 ksi. Of course, it also comes down to proper technique, experience of the welder, and whether the weld is done correctly to provide a sufficient amount of strength. 

Metal Penetration 

It is tough to really compare flux core welding and MIG welding when it comes to metal penetration. This is because penetration comes down to more factors than just the method of welding. It also has to do with the voltage and amperage that the welding machine is set to and the particular thickness of the metal. 


In most cases, the ideal welding method comes down to preference. Some of those who will argue for a particular method may have just learned that particular approach first and find it to be their preferred method. All this really means is that beginner welders may want to try both and see which one they find to work for them and the specific application.

Looking to Learn How to MIG Weld or Flux Core Weld?

If you are looking for some new welding equipment, whether you are a beginner or master welder, Welding for Less is here to help. We offer a wide array of welding equipment, tables, and accessories to ensure that every welder can find what they need. If you have questions, feel free to call us at 1 (877) 219-3936 or shoot us an email at

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Glenn Kennedy - March 30, 2023

Thank you very much for takeing the time to write this very informative literature on the subject of mig vs flux core my son finally gets it .thank you

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