What is Flux Core Welding Used For? Learn 12 Best Uses

By Bill Byers / January 21, 2019
What Is Flux Core Welding Used For Title Image

You've heard about flux core welding, you may even be interested in getting a welder and welding up something yourself.

Or perhaps flux core welding is of more academic interest.

Either way, I aim to tell you here what flux core welding is used for and help you learn the 12 best uses.

​What is Flux Core Welding Used For?

  1. ​​When Portability is Important
  2. ​When Welding Outdoors
  3. ​When It is difficult to Pre-Clean Your Metal
  4. ​For Thicker Gauges of Metal
  5. ​For Galvanized Steel
  6. ​For Welding Mild Steel, Stainless Steel, some forms of Nickel
  7. ​When Fast Welding
  8. ​When Out of Position Welding
  9. ​When The Look of the Weld is Not So Important
  10. ​For Beginners Welders
  11. ​When you are Low on Volts
  12. ​In Industry and For a Variety of Projects

Learn more about each of the 12 best uses by reading on ..

​YouTube Video Showing Flux Core Welding In Construction

​​I found this YouTube video showing one of the areas flux core welding is great for within construction. An example of where there is thick metal to be welded up quickly - and in this case you can see flux core welding of a column onto a base plate.

Flux Core Welding Structural Steel Project

Video Credit: Zanjasteabro


This article concentrates on the instances, situations and reasons that flux core welding is used for. But it is important understand a few things about flux core welding if you are not aware of them already.

Not sure what Flux Core Welding is? Then head over to my document on the site that will tell you all about it.

Don't know exactly what a flux core welder is? Then take a look here.

Unsure about what flux core wire is and the fact that there are two types of flux core welding wire - self shielded and gas shielded. Then check out my article about flux core welding wire.

​1. Flux Core Welding is Used Where Portability is Important

​And what do I mean by that?

Because when you are flux core welding, as long as you have the means of generating power at the welding site and of course your safety equipment, all you need to take with you is your flux core welder and have it installed with some appropriate flux core welding wire.

There is no need to worry about transporting a separate cylinder of high pressure gas as well. Anyone who has transported a tank of gas knows they are heavy, awkward to lift and need to be transported with care.

As the gas inside is under pressure and Argon gas can silently suffocate if leaked within an enclosed space like the inside of a car or the cab of a truck.

Less to carry.

There are no separate rods of welding wire to take to your welding site as in stick welding. Where taking insufficient rods with you means that you have to stop welding and go get some more.

A flux core only welder can be lighter and easier to carry when welding in difficult to access places - I read of one person using his flux core welder up a ladder - something that would be more difficult with other forms of welding.

​2. Self Shielded Flux Core Arc Welding is Preferred for Welding Outdoors

​Even quite high wind doesn't affect flux core welding. Because the self shielding flux core welding wire produces shielding gas at the point of the weld to protect the melted metals from the atmosphere.

Hot molten metal when subjected to the air we breathe without any form of protection produces welds that are poor and fail.

The separate shielding gas as used in MIG welding to protect the weld would just be blown away with the wind. Erecting wind barriers can help but if they are not positioned correctly then a bad weld will result.

Flux Core Welding is the choice when you need to fix a broken tractor or machine part out in the middle of a windy field.

​YouTube Video Showing a Farm Repair Outdoors

​This 3 minute 27 second video from Miller Welders shows flux core welding on a farm part - a heavy duty trailer hitch. A good example of flux core welding outdoors.

Farm Welding Repair. Rebuilding a Trailer Hitch

Video Credit: Miller Welders

​3. Is Used Where the Metal Cannot be Easily Pre-Cleaned

​Metal that has any rust or mill scale or galvanization must be cleaned first before MIG and TIG welding. This is quite not the case with flux core welding.

Clean metal is preferred but in the situation where you do have a broken tractor or machine part or gate that can't be easily taken into a workshop situation and scrupulously cleaned then flux core welding is the choice.

Paint and oil should be removed - get rid of as much as you can - otherwise when welding in the rough choose flux core welding.

​4. Flux Core Welding for Thick Metal

​Flux Core welding is known for its good penetration thick gauges of metal.

This is why this method of welding has been used in the structural steels industry.  Gas shielded flux core welding in particular is great for thick metal penetration.

Self shielded flux core welding is pretty good too. You can weld 1/2 inch thick metal with a single pass with flux core, compared to MIG welding where the same welder, with the same level of voltage output would only be able to weld 1/4 inch with a single pass.

​5. Use Flux Core Welding When Welding Galvanized Steel

​Flux core welding is a form of welding that allows the welding of steel with galvanization on. There are other forms of welding that demand the galvanization is grinded off first.

Where there is galvanization we're normally talking about an object that needs to live outdoors, like a gate, or pipe or fencing and so galvanization has been used to protect the steel.

That galvanized item may not be so easily taken into a workshop and welded, as it may be a small part of a larger object that is difficult to move.

If you need to weld through galvanized steel then flux core welding is your choice.

 Welded Railings

Welded Railings

​6. Flux Core Welding is Used for Welding Which Metals?

​Flux core is most commonly used to weld mild steel and low alloy steel.

There are forms of flux core welding wire that can weld stainless steel but this demands a welder that is well powered (120 volts and above) as welding stainless steel with flux core takes power to weld.​

Stainless Steel Flux Core Welding

​Stainless Steel Flux Core Welding

​Flux core is also able to weld some forms of nickel alloy.

Some believe flux core can weld Aluminum, but there is no flux core wire for Aluminum welding. Take a look at my article "Flux Core Aluminum Welding Wire, I want it Now" to find out why.

Flux core, because it is a hotter process is used on 20 gauge metal at its thinnest up to 1/2 inch thick steel and above if you have a powerful enough welder.

You choose flux core welding when you want to weld thicker metals.

​YouTube Video Showing Flux Core Welding in High Wind

​Earlier I wrote that flux core welding is particularly good when welding outdoors and in high wind. And this video shows this very well.  In fact the wind is so high it is difficult to hear the video-er speak. But please don't hold that against the video it's a good one as it also shows how a cheap low end flux core welder can be used to weld thin tubing.

I wrote earlier that flux core welding is really used for 20 gauge metal at its thinnest.

Here he is welding 24 gauge. To do that he has to use a series of very short tack welds to prevent blowing holes through the thin steel. It takes experience and skill to do this. It also takes care and time, as you will see in this video. And he has quite a wind blowing.

Flux Core Welding Thin Tubing

Video Credit: TheToolReview

​7. Where Fast Welding is Needed

Flux Core welding as it is a hot process, melts the base metals and deposits the filler wire quickly into the weld. It does this more rapidly when compared to MIG welding.

When coupled with its lack of need for highly cleaned metal. The preparation for welding is shorter and you can just get on and weld something up as long as you have the right settings for your welder.

Flux core welding is the method of choice when you have a lot to weld in a short time and that is why it is loved in the construction and shipbuilding industries.

Self shielded flux core wire is great at this and gas shielded flux core welding is even better at welding fast, thicker metal gauges with great metal penetration.

​8. Flux Core Is Preferred for Out Of Position Welding

​The flux core welding wire used in flux core welding has forms of the wire that is used for flat, horizontal welding only.

There are forms of the wire that can be used for all position welding. This means welding vertically, overhead or uphill. This is called out of position welding.

Flat welding is the easiest and preferred position to weld in because you are above the weld and physics and gravity help you.

Out of position welding is harder, demands more skill from the operator to move with skill, to produce a weld that penetrates the metal, yet move quickly enough to not drip the hot molten filler metal out of the weld and onto yourself and your surroundings.

The properties of flux core welding lend itself to welding out of position - with the right type of flux core wire of course.

​9. Where the Look of the Weld is Not the Highest Consideration

​Flux core welding, particularly the self shielded form, without the correct settings can produce a lot of spatter.

This can affect the look of the weld and the immediate surrounding area of the weld.

And wrong settings means that the slag coverage over the weld is hard to take off. Both these things result in more time taken up in cleaning up after you have welded, particularly if you need to paint the weld or spray galvanization back on.

This means that flux core welding is chosen when the strength of the weld is more important than its good looks. 

It doesn't mean you can't get decent looking welds out of a flux core weld. You can, with the right settings, practice and skill. Even so flux core welding isn't the method of choice when a good looking weld is needed. An example of this is a car panel, where the weld needs to be primed and painted afterwards and you want a pristine looking weld.

Flux Core Farm Welding

Flux Core Farm Welding

​10. Flux Core is Great for Beginner Welders

Where the welder operator is new or has low welding skill, flux core is a good choice.

The process is just more tolerant of the rough skills of a new welder.  Once the flux core welding machine is set up correctly a user with poor hand skills can produce a good weld with a few hours of practice.

And what I mean by a good weld is a weld that will hold.  It may not be the prettiest of welds but it will hold.

​11. Choose Flux Core When you have 110 Volts

​If you have only a limited budget and limited electrical power output options to you flux core welding is a great choice.

This is because the nature of flux core welding gives you good metal penetration versus the electrical input put into the weld.

I have done a round up of the best flux core welders under 200 dollars for those of you who are interested in the entry level part of the flux core welding market.

Where you have limited power choices whether in your own workshop or from a generator out in the field, you'll be able to weld thicker metals for the volts put in ​with flux core welding.

And this does not have to be limited to 110 volts. It is right the way across the amperage range. You get more welding output from flux core welding compared to MIG or TIG welding.

​12. Flux Core Welding Projects

​Welding projects that are typically flux core welded;

Shop fabrication, construction, ship building, architectural work (where the aesthetics of the weld is not important), repairs around the home, farm, ranch and yard, underwater welding, hobby welding, pipe connections, gates, fences, art projects.

​YouTube Video Illustrating How Flux Core Welding is Used in an Art Project

​In this 7 minute 13 second YouTube video, I found a nice example of how flux core welding can be used to make something pleasurable and good to look at. In this video Ian talks you through how he goes about creating a welded flower.

Something, that would be lovely as a gift for a welder to give a loved one, perhaps on Valentines Day.

He is using a MIG welder that can also weld with flux core wire to do his flux core welding.

Welded Flower

Video Credit: Ian Birtch

​Last Words

​I hope you enjoyed my article "What is Flux Core Welding Used For? Learn 12 Best Uses". Whether to choose flux core welding or MIG welding does depend on what you need to weld, where you are welding and the effect you're looking to achieve.