Flux Core Vs MIG Welding


Welding is a form of art for passionate welders. So, there are different views on the preferability of varying welding methods. While some prefer Flux Core welding to be better than MIG welding, others prefer vice versa. There is always a reason behind whatever welding technique they choose.  

Both Flux core and MIG welding have similarities and differences. So, we thought of comparing both the methods and see where which excels over the other. This comparison will help everyone to understand the differences better and practice one accordingly.  

When choosing among these two methods, three factors play the most crucial part. They are the used material, welding area, and the exterior finish surface. But before going into the comparison, some basic knowledge of both methods would be excellent.  

What is Flux Core Welding?

Flux Core Arc Welding, or FCAW, was first used in the 1950s as an alternative to Manual Metal Arc (MMA) welding. Flux Core welding is also called stick welding. The method is only used in flux core welders. It uses a tubular wire that is filled with flux. 

Flux Core Welding
Flux Core Welding

The wire is hollow, and flux powder helps to shield the weld from atmospheric contamination instead of gas. Direct current, electrode positive (DCEP) is commonly used as in the FCAW process. 

There are two types of these process variants; self-shielded FCAW (without shielding gas) and gas shielded FCAW (with shielding gas). The difference between these two is that gas shielding requires a gas supply to protect the weld, whereas no external shielding gas is required self-shield

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What is MIG Welding?

Metal Inert Gas or MIG welding is an arc welding process. It uses a continuous solid wire electrode heated and fed into the weld pool using a welding gun. In this process, you melt two base materials together and form a join. 

The gun then feeds a shielding gas alongside the electrode. The purpose of using inert gas is to shield or keep off airborne contaminants from the weld area. It, thus, makes it ideal for different welding kinds of aluminium and non-ferrous metals.

MIG Welding
MIG Welding

This method was first patented in the USA in 1949 for welding aluminum. It is a versatile technique that is suitable for both thin sheet and thick section components. 

Both MIG and Flux Core will give you ground welding. But there is still some considerable difference between them. Ahead in this article, we will be talking about these differences from a broader perspective. 

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Difference between Flux Core Welding and MIG Welding

1. Shielding Gas

One of the fundamental contrasts between these two welding methods is the use of shielding gas. Shielding gas plays a crucial role in MIG welding. So, it would help if you bought a pressure gas tank connected to a regulator or a flow meter to the MIG welder through a running hose. 

There are several gasses that you can use as protection in MIG welding. For example, you can use a combination of argon, carbon dioxide, and helium as protection for stainless-steel.

Welding Gas Setup
Welding Gas Setup

As mentioned earlier, there are two FCAW welding processes- self-shield and dual shield flux core. Self-shield flux core is a process where the wire produces its own protection gasses while welding. Heat melts the flux and produces gas which then covers the weld pool.

Flux Core is an economical process since you do not need to purchase a separate pressure gas tank to weld. However, just like in MIG welding, dual shield flux core wire needs to be used together with shielding gas. 

2. Type of Wire

The type of wire used in both these welding methods is another main point of comparison. Both these methods require a welding wire to create a weld pool. But there are differences in their types. The flux Core method uses a tubular wire for welding, whereas we use a solid wire electrode in the MIG process. 

Welding Wire
Welding Wire

Tubular welding wire is a hollow wire with flux inside and metal outside. While heated, the flux starts melting, and it then produces gas. Both these welding wires have different usage. Therefore, you cannot use a solid wire to weld with flux core welders.

3. Metal Penetration 

There has always been an opinion that flux core offers better metal penetration than MIG. However, the conclusion is not that simple. There are certain deciding factors for this. For example, the voltage and the amperage to which you set your welder is the first determinant of how deep welding will penetrate metal. 

Metal thickness is also another deciding factor here. The thickness of the metal decides how deep the penetration will be. However, by using flux core, you are better positioned to weld thicker metals with less amperage than MIG. Therefore the argument that flux core offers better metal penetration is correspondingly valid.

4. Welding Quality & Appearance

Welding quality is not just about the strength or durability of your weld. There are many other quality deciding factors too. Even if strength is one of the primary determinants, then both these methods can provide you with durable weld. 

Test Pipe Welding
Test Pipe Welding

But if texture and looks are a quality determinant, the MIG welding process wins it. In this process, the filler metal is set to sit up the joint weld. It gives you an excellent-looking weld joint.

5. Price

Price is another point of consideration when it comes to different welding methods. So, which is costlier among these two processes? Some people are of the opinion that MIG is the cheapest since it uses a solid wire. Solid wire is undoubtedly less expensive than that used by flux core welding wire.

But MIG also requires other additional equipment, and it increases the cost. For instance, you need to buy a gas pressure tank and all the components, including a flow meter, a hose, and a regulator.

Our Ratings

For Flux Core Arc Welding or FCAW

Flux core arc welding is one of the well-practiced welding methods. Following the comparison, we have come to know about many pros and cons of this process. Therefore, it is undoubtedly a challenging competitor to MIG welding. Flux core is a cheaper welding process than the MIG method. Flux core is also efficient in thick metal penetration. 

But on the other side, it is not suitable for thin metal penetration, and neither gives a smooth or excellent-looking welding finish. Considering both the pros and cons of Flux core welding, our team rates it 4.7/5

For Metal Inert Gas Welding or MIG

MIG welding is another popular Arc welding process. The comparison above has shown us its various pros and cons. This welding process is faster and simpler than flux core welding. Moreover, the welding quality is also durable with excellent finishing. It can efficiently weld both thick and thin metal plates. 

Yet MIG welding is a little costlier than its competitor. Plus, it is not suitable for welding outside or in drafty conditions. Considering both sides, our team rates it 4.8/5. So, MIG welding wins the competition with a slightly higher point. 

Frequently Asked Questions (FAQs)

Q1. Is MIG Welding suitable for thin sheets?

Answer: Unlike Flux Core welding, MIG welding is a versatile technique that is suitable for both thin sheet and thick section components. A MIG welder with decent wire control and power is preferred for welding thickness of anything less than 0.8mm.

Q2. What is shielding gas best for MIG welding wire?

Answer: The shielding gas that you choose depends on the wire and the application. CO2 provides good penetration when you weld thicker materials. You can also use it on thinner materials considering it tends to run cooler. 

It thus decreases the risk of burn-through. If you want better weld penetration and high productivity, use a 75 percent argon and 25 percent CO2 gas mix. The combination will also produce less spatter than CO2. Hence, there will be less post-weld cleanup.

Q3. What is inside the flux core wire?

Answer: Flux-cored wires are a process developed in the 1950s and are available in two main versions: self-shielded and dual-shielded. Both these types are composed of an outer sheath and are filled with flux. 

Flux is a compound that is a mixture of alloys and deoxidizers. When heated, it melts and produces gas which is necessary to protect the weld from contaminants. On the outer layer, there is the metal sheet required for welding. 


Briefly, we can say that this assessment was helpful enough to point out the differences between both these methods. Both these methods have their advantages over the other. While MIG is widely used in most industry sectors and estimates for more than 50% of all deposited weld material, FCAW is suitable for all position welding, given the correct filler material and flux composition. Hence, both have specs that make them fit in different welding applications.

When choosing the right welding method, it is essential that you evaluate your needs first. Decide what metal you will weld, what results from you would want, the environment, and how much you are okay to spend for the entire setup. Also, your selection of the right welding machine plays a huge role in either welding method. That said, we hope that we were able to help you eliminate your doubts accurately.