Flux Core Welding vs. MIG. What Type of Welding is the Most Convenient?

Flux Core Welding vs. MIG

Professional welders often argue on which type of welding is the most convenient for a certain application. It is the case of flux core welding versus MIG.

Both welding types have some similarities and differences, which argue in favor and against each of these welding types.

The truth is that, in general terms, no method can be considered absolutely better than the other.

You have to take into account some specific characteristics of the work that you’ll perform. What will you weld? Where? What finish do you intend to get after welding?

Hence, the most important thing is to learn about the conditions under which each type of welding will provide better results.

In this article, we aim to inform you about the essential criteria to determine which type of welding will be more suitable for your particular case.

What Is Flux Core Welding?

Formally known as flux-cored arc welding or FCAW, this technique uses a wire as an electrode. It is connected to an electricity source with the help of a special cable.

An electric arc heats the wire, which is deposited in the welding. The wire is fed to the weld using a special welding machine. To shield the weld from contaminants, you can use two possible methods.

The first one implies using shielding gas. Typically, it can be CO2, oxygen, or an inert gas such as argon or helium. This technique is pretty much similar to MIG welding, which we will explain below. 

The second method relies on shielding gases released when the core of the wire fluxes. It is a rather easy-to-learn technique. Most welders begin their professional training with this kind of welding.

What is MIG Welding?

This welding technique, formally known as metal inert gas or MIG, implies using a wire as well. Just like in FCAW, it serves as an electrode. Also, a shielding gas prevents the weld from being contaminated.

However, in this type of welding, an external source of gas is used. The gas is fed using a hose. A special welding gun holds the electrode and allows a steady flow of the shielding gas.

MIG is an effective welding technique to weld metals such as aluminum, stainless steel, and other nonferrous metals. This feature has made it very popular in car manufacturing and the construction industry.

Welding Quality: Flux Core Welding vs. MIG

The quality of the weld is a determining factor to decide which technique to use. It is generally accepted that MIG provides better quality. It may be the result of the use of shielding gas, which is more effective at preventing contamination of the weld.

But what exactly will we refer to as “quality”?

If by quality, we mean the strength of the resulting weld, both FCAW and MIG are at the same level.

However, if we refer to the look of the weld as quality, then MIG is the winner. The resulting weld using the MIG technique has a more pleasant texture and appearance.

Does Flux Core Offer Better Metal Penetration than MIG?

There is a consensus that FCAW penetrates metal better than MIG does. However, we have to understand which factors determine metal penetration. Hence, this characteristic may change depending on these parameters.

For starters, the electrical voltage and the current that is applied to the electrode determine how deep the welding penetrates the metal.

But the thickness of the metal also plays a role. Depending on it, the welding may or may not penetrate much in the metal.

In general, you can use FCAW to weld thick metals with less electrical current in comparison to MIG. Hence, with the same amperage in both cases, FCAW will achieve higher metal penetration.

Which Welding is Cheaper?

At first sight, one may think that MIG is much cheaper. Many welders come to this conclusion considering the type of welding wire used for each technique. MIG requires a solid wire, whereas FCAW uses a flux core wire.

Manufacturing the flux core wire incurs higher production costs. And true, this type of welding wire is more expensive.

However, it is the extra equipment needed for MIG that makes this type of welding more expensive than FCAW. For MIG, you need to get a pressurized gas tank and its accessories. This increases the overall cost significantly.

Where Can I Weld with Each of these Techniques?

One of the important factors to decide which welding technique to use is the location where you will weld. MIG has to be used necessarily indoors or in enclosed environments.

Hence, you must have an enclosed workshop where you can do this type of welding.  It is necessary because the wind could alter the effectiveness of the shielding gas. If you must use MIG in an open space, then you need to use a windshield.

On the other hand, FCAW doesn’t use a shielding gas. Hence, this welding technique is suitable for open spaces.

Pros and Cons of Both Welding Techniques

As seen, both techniques have their advantages and disadvantages. Let’s summarize them below.



  • It works in open environments and under different weather conditions
  • It is more effective to weld thick metal
  • Less equipment needed for welding
  • A gas tank is not needed
  • The overall cost is lower than that of MIG


  • Not recommended for thin metal



  • It creates a better-looking weld
  • Maintenance is not complicated
  • It is easy-to-learn and suitable for beginners
  • Slag and spatter are easy-to-clean


  • Not recommended for welding thick metal
  • It needs more equipment, which makes the initial cost higher than that of FCAW


As stated at the beginning of this article, none of these two techniques can be considered better than the other. Both FCAW and MIG have their advantages for some specific scenarios.

Hence, before you choose a welding technique, consider your particular needs. Where will you weld? What will you weld? What do you want the result to look like? The answers to these questions will help you to choose the right option.

Flux Core Welding vs. MIG

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