MIG vs Flux Core Welding – Differences Explained!

There are a number of welding methods you will come across as a welder. Some prove more popular or easier than others. At the end of the day, choosing the correct welding method depends on some simple points.

We will talk about various factors regarding the MIG and flux core welding today. Honestly, MIG welding is more well-known and possibly one of the first welding techniques you will learn. But in certain situations, flux core can be better.

As the knowledge of both are equally important in your welding career, let’s find out the difference and similarities between them-

MIG Welder – What Is It?

MIG Welding Stands for metal inert gas welding. It is an old welding technique that uses a machine-fed wire in order to create the arc. The arc that appears in the middle of the electrode and workpiece produces extreme heat.

MIG welding is popular among all welders and is suitable for welding large and complex structures. It is easy to get the hang of MIG welding. You will need to use one hand when welding with this method.

Flux Core Welding – What Is It?

The name flux core welding actually means flux core arc welding or FCAW. Like MIG, it is an arc welding method that uses electrical current to make the weld. The wire that works as the electrode is consumable and needs replacement after each usage.

Remember that flux core welding is also a gas welding like MIG. The choice of gas can be similar to MIG as well. But you do not need to provide additional gases when it comes to self-shielding flux core welding.

MIG Welding Basics

The process of MIG welding is simple. There will be a solid wire to works as the electrode and conduct the electricity. Since the wire works as a filler material itself, it delivers the filler to the weld.

For any MIG welding setup, you will need to get a MIG welding machine and a gas cylinder containing argon or helium. You can get a deep penetration result from MIG welding. Another thing to note is that you can hook up a MIG welding using both AC and DC.

Flux Core Welding Basics

The term flux core derives from the type of wire that it uses as the electrode. These wires have a filer layer to the outside while fluxes in the core. As you weld, the flux-center melts to create a shielding gas around the weld pool.

It is a reason why flux core welding does not need external gases. However, there is dual-shielding flux core welding, where you need to provide an additional gas cylinder connection.

Both variations of flux core welding methods leave slags. But it is easier to remove the slags from the dual-shielded one.

Similarities of MIG and Flux Core Welding

These two welding methods are really similar if you analyze them. From the process of welding to the setup and applications, you can find many resemblances. We have listed some of them below.

  • Both are gas welding method and uses gas to protect the weld pool.
  • They use consumable electrode and doesn’t need additional filler materials.
  • The wire spool in both cases conducts the electricity needed for the weld, and the arc shows up at the end of the wire.
  • Only in the case of dual-shielding flux core and MIG welding, they use the same connection polarity- DCEP. Self-shielding flux core uses DCEN.
  • They both deliver a strong weld if you weld the right metal and settings.

Differences of MIG and Flux Core Welding

There are lots of differences between the two welding techniques. When one tops the other, it is the opposite in another way. You should learn these factors well.

  • MIG welding must need additional gases. The self-shielding flux core provides that gas from its core flux.
  • Slags left by MIG weld can come out quicker than self-shielding flux core. Then again, the dual-shielding flux core can provide a better slag removal than MIG.
  • MIG welding uses solid wires, where flux core uses tubular wires.
  • Self-shielding flux core welding uses the DCEN connection. So, the electrode part stays on the negative polarity. MIG uses the DCEP, which is the complete reverse method.
  • The positive side of the connection gets more heat than the negative. So, a MIG electrode wire gets hotter than a self-shielding flux core wire. Although, you can use DCEP on the dual-shielding flux core.
  • MIG method can weld thinner metals than flux core. However, MIG cannot weld metals with too much thickness that flux core can.
  • Flux core welding is much efficient than MIG. For instance, to weld the same metal thickness, MIG needs more amperage than flux core. In this case, you can get a deep penetration from the flux core faster than MIG.


These are some applications where MIG and flux core welding are ideal to use-

  1. 1
    Any low alloy steel.
  2. 2
    Both can weld mild steel.
  3. 3
    Flux core is good at galvanized steel.
  4. 4
    For aluminum, you should use MIG.

Frequently Asked Questions

Is Flux Core Better Than MIG?

It depends on various factors. Based on the removal of slag formation, dual-shielding flux core can be better than MIG. But you can’t weld aluminum with flux core.

Flux core is more energy and cost-efficient, on the other hand. So, you cannot really call one better overall than the other.

Can I Use MIG Wire in a Flux Core Welder?

No, or at least, it will not be a good idea to do so. MIG and Flux core use different wire types in their welding process.

Does Flux Core Wire Go Bad?

It is true that flux core wires can go bad over time. Most of the time, the reason behind it is the moisture. You may need to replace the electrode occasionally.

Final Note

As a welder, you should not lean towards only one welding process while ignoring the other. In many cases, while both methods can weld the same metal, one can do it better. So, you should practice MIG and flux core in different situations.

Since they are gas welding methods, you will need to weld indoor in both cases. Otherwise, the wind can blow the shielding gas away.

Based on the workpiece, choose the correct welding technique, amp, and connection. Thus, you can get the strong joint and perfect outcome that you want.

Last Updated on 1 year by Richard Boyer

  • June 8, 2022
Richard Boyer

Richard Boyer has been a professional welder for over 27 years of his life, and now he is a trainer and blogger providing critical information to anyone interested in welding. He is helping out both hobbyists, novice and professional welders to learn newer and better techniques. Read more about me

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