Is Flux Core Welding Any Good? (Basic Welding Techniques)

Welding is the art of joining metals and plays a major role in manufacturing, energy and construction industries. If you’re researching welders for the first time you might be confused between different welding methods and what they’re good for. Flux core welding is one of the most popular methods and probably the easiest to learn.

If you’re wondering “is flux core welding any good?” and the potential advantages of flux-core welding, we anwer it here.

Is Flux Core Welding Any Good?

Is-Flux-Core-Welding-Any-Good

Understanding Flux Core Welding

Flux core welding get its name because it contains “flux” inside a consumable electrode wire that feeds through a welding gun. The flux vaporizes and turns into inert gas when the electrical arc melts the wire. This gas expands to protect the weld puddle from the outside environment (oxidation).

You may also hear the term gasless MIG welding or metal active gas (MAG) instead of flux core welding. This just means the electrode wire itself contains the materials to create a protective gas shield around the weld. A flux core welder can also be set up with an intert gas bottle and non-flux core electrode wire.

With flux core welding you can use different types of wire to match the base metal you’re working on, such as mild steel, stainless steel, chrome alloy, etc.

Wide Range of Applications

With flux core you can weld basically anything with made of ferrous metal.

Flux core welding can be used for:

  • Light repair jobs
  • Fence building
  • Metal artwork
  • Spot welding
  • Automotive welding
  • Underwater welding
  • Pipeline welding
  • Shipbuilding
  • Production manufacturing
  • Roll cages
  • Frames and bumpers
  • Furniture building
  • Tool repair

Flux Core is 100% Self-Sufficient

One benefit of flux core welders are that they are 100% self-sufficient. This makes them similar to a stick (arc) welder, but with more control over the wire speed. All you need is an electricity source and the right roll of wire.

In comparison, an inert gas MIG welder with a gas bottle and non-flux wire increases the cost, complexity and weight of your welding setup. A cart is necessary too, which reduces your mobility. The gas bottle will run out so you can’t travel too far from a welding supply store.

Good Quality Welds

Flux core welders can produce consistent quality welds with excellent penetration, particularly on thicker materials. The gas expands away from the weld puddle at a consistent rate and volume. This makes for consistent high quality welds, particularly in a protected indoor environment where the gas cannot be blown away.

If you are a beginner or intermediate welder, flux core MIG removes the need to adjust gas flow and pressure. No matter what wire speed you’re using, the gas flow will be near-optimum to shield the weld.

Flux core welders are used extensively in production manufacturing because they produce highly consistent welds quickly with good penetration and lower consumables cost.

Flux core welding is not all rosy, however.

The main downside of flux core welding is the cloud of gas and smoke makes it difficult to see the weld. This can lead to inaccurate weld placement and poor distance control. Both can negatively affect the quality of your welds.

Easy To Learn

Flux core welding is the easiest welding method to learn for the beginners. With only a few hours of practice you can lay down reasonably good quality welds — good enough for fence building and minor tool repairs where weld appearance isn’t important. Don’t expect to be good enough to build a roll cage or anything safety-related with only a few hours practice, however.

The reason it’s easy to learn is that a flux core welder has fewer inputs to master. All you have to know is how to move the gun, which voltage/wire settings to use, and the right electrode wire. The basic setup parameters can be found in standard settings table that comes with your welder.

Flux core MIG is also easier to learn than stick arc welding. You don’t need to “strike an arc” with a MIG welder and the gun tends to be more consistent than a stick which constantly becomes shorter as you work.

Flux Core Welding Cost

Consumables such as wire and gas cost money.

With inert gas-shielded MIG welding, you need to pay for a constant supply of both wire and gas. Combined with the cart and rack, a gas-shielded MIG welder can cost a hefty amount.

With flux core welding you just pay for rolls of wire. However, flux core wire is about twice as expensive than standard MIG welding wire for the same thickness.

Stick (arc) welding has the lowest consumables cost, but the weld speed is about 50% of what a wire MIG welder can produce, since you have to change sticks regularly. This factors into the cost if you’re paying for labor.

Weld deposit efficiency is a big cost factor, as well:

  • With self-shielded flux core wire, you will typically end up with about 78% or so of the wire in the actual weld. The remaining 22% burns off as gas or is deposited as slag on the surface.
  • With inert gas metal arc MIG (GMAW) using 75% argon / 25% CO2 96% of the wire ends up as weld.
  • With stick (arc) welding about 60-65% of the electrode is depsited as weld. (Source: ESAB)

Here is a general comparison of the costs of flux core MIG welding vs. gas MIG welding vs. stick (arc) welding:

Welding MethodConsumableCost / Pound of Weld
Flux Core MIG0.030″ (0.8 mm) wire – Lincoln Electric Innershield NR211-MP flux core (PRICE = $13.67 per 1 lb spool @ Home Depot). 78% deposited as weld. $17.52
Gas MIG5 cubic feet of Argon / CO2 mix gas (PRICE = $2.00 per cubic foot)$10.00
0.030″ (0.8 mm) wire – Lincoln Electric SuperArc L-56 ER70S-6 (PRICE = $13.67 per 2 lb spool @ Home Depot). 96% deposited as weld.$7.12
TOTAL$17.12
Stick (Arc)1/8″ (3.175 mm) 7018 mild steel stick electrode – Lincoln Electric Excalibur 7018 XMR (PRICE = $175 for 3 x 10 pound cans). 65% deposited as weld.$8.97

Advantages of Flux Core Welding

Here are the reasons why is flux core welding is good:

  • Flexibility: Flux core welding can work in any direction; vertical, horizontal, flat, overhead, forehand, etc.
  • Versatility: You can weld basically any type of ferrous materials with the right wire selection. Flux core welding works on metal with rust, dust or dirt as well.
  • Mobility: Flux core welders are simple, relatively lightweight and highly mobile; you can take them anywhere and start welding right away with an adequate electrical source.
  • Low skill level: Flux core welding method requires a very low skill level to work with. You need less experience to master the process and produce decent weld quality. It does take greater skill to produce high quality welds by hand due to the smoke covering the weld pool, however.
  • Faster: Flux core welding is about 50% faster than stick arc welding.

Disadvantages of Flux Core Welding

There are several reasons to avoid flux core welding:

  • Poor Weld Appearance: The gas and smoke cloud that emanates from a flux core weld pool hinders visibility, making it difficult to maintain weld accuracy and distance from the surface. This means your welds are likely to be “ugly” and inconsistent as compared to inert gas MIG welding. Flux core welding also leaves burn marks and slag on the weld area that must be chipped and cleaned off.
  • Smoke and sparks: As the solid materials from the flux core vaporize into protective gas, the expanding cloud creates a lot of smoke and sparks. This is hazardous to breathe and very difficult to see through when you’re trying to weld accurately. Flux core welding and stick arc welding both have this “dirty welding” problem.
  • Bad for thin material: Flux core welders work best on thicker materials, since the heat at the weld point is higher than inert gas MIG welding to ignite the flux and gases. It is difficult to control the weld and avoid burning through thin materials.
  • Affected by wind: Although less of a problem than inert gas MIG, flux core welding is still affected by the wind. Breezy weather blows the shielding gas away from the weld, leading to inconsistent porous welds from oxidation. If you plan to weld outdoors often, it’s best to use stick welding.

Frequently Asked Questions

Is flux core welding hard?

No. Flux core welding is one of the easiest welding methods to learn for beginners. All you have to know is the machine settings for the material you’re welding (found in a standard table that comes with every welder) and the angle you’re going to hold the gun.

Can you weld stainless steel with flux core?

Yes, you can weld stainless steel using the flux core welding method. However, you must make sure that you’re using a stainless steel consumable electrode.

Can flux core weld galvanized steel?

Yes, but it’s very dangerous! The zinc coating on galvanized metals is extremely toxic when melted (zinc vaporizes at 1650 F while steel melts at 2750 F). You should only weld galvanized metals while wearing a full protective suit and respirator designed for the purpose. Galvanized coatings also cause bad weld porosity, which significantly weakens the weld.

Flux core is better at welding galvanized steel than inert gas MIG. The expanding gas shield and higher heat burns off the zinc better. Pulling the welder, rather than pushing, helps to push the zinc ahead of the steel weld puddle and delivers stronger welds.

Is flux core welding the same as MIG welding?

Flux core welding is a type of MIG welding, where the inert gas come from the flux-cored electrode wire. Inert gas MIG is the other type of MIG welding and uses bottled gas to protect the molten weld. Both flux core and inert gas MIG can usually be done with the same machine.

Conclusion

Flux core welding is a self-contained process where the electrode wire itself shields the molten weld pool from oxidation and contamination. Its simplicity and ease of use makes a flux core welding machine a good starting point.

Beginning welders, those on a tight budget, and welders who want a highly mobile machine will all find flux core welding suits their needs. It can work in a variety of metal types, it welds at different angles easily and produces strong welds on heavier materials.

The only downsides are the amount of smoke and slag produced, and the difficulty welding thin materials. Other than those things, flux core welding is definitely good.

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