Flux Core Aluminum Welding Wire, I Want It Now

By Bill Byers / March 7, 2018

You have a 90 Amp or 130 Amp MIG welder – well in truth it is a Flux core arc welder because it uses flux core welding wire only. It’s the reason you started on this search.

You have this little job you’d like to do but the base metals are Aluminum.

What do you do?

There is steel based flux core welding wire. You already have a roll of that and it works great. Can you do a sneaky weld using that? Would it work?

What you really want is a roll of the same with Aluminum in it? You know, flux core Aluminum welding wire.

And you want it now.

Your Google Search

Your Google Search

You’ve type in the search and it’s led you to here. I’ll tell you the truth. Is there such a thing as flux core Aluminum welding wire?

A search for flux core Aluminum welding wire on Google shows you a bunch of adverts. Some even claim they are flux core welding wires. Others are clearly reels of solid Aluminum wire and you know your MIG can’t use that.

Cause that stuff needs Argon gas.

But you know, some look tantalizingly like what you want, but the stark truth is that none of them are suitable for welding Aluminum in your Flux Core MIG welder.

And if you do use that stuff then you’re going to need new welder soon.

The unicorn the holy grail of MIG welding

Is flux core Aluminum welding wire a unicorn, that mythical creature. Yes, so why does the rumor of its existence raises its head every few years?

The Truth about Aluminum Flux Core Wire

Even when the welding wire says flux core in the ‘title’ a closer inspection may reveal

  1. It is solid wire and the small print says Argon gas is recommended. Actually it’s more than recommended it is crucial and what’s more you’re going to need a MIG welder that uses gas. i.e. the wire is for MIG welding not gasless flux core welding at all. Or
  2. it is soldering wire. Again a process that has nothing to do with MIG welding. Or
  3. It is Aluminum wire, flux core yes, but actually designed for brazing machines that have an automatic wire feed or for use in a furnace where the air is tightly controlled. Or for use in an induction brazing process, or wire for use with a propane gas torch or a torch that produces a flame. All this means it isn’t MIG wire but brazing wire. So what? I’ll explain further below.

Where can I find Flux Core Aluminum MIG Welding Wire for Sale?

And I get why people are searching for this unicorn. You have a $100 flux core only welder and you have a small project. Your budget doesn’t stretch to a more expensive MIG with gas just for this bit of Aluminum work you have. But there are really good reason’s why there is still no sign of this unicorn.

No Sale

There is a great article from The Fabricator.com by Frank Armao of Lincoln Electric on the subject. Frank Armao was cited in the article as being a member of several relevant American Welding Society committees. The article is dated 2013 and is still valid today.

The points he covers in that article are;

  1. The American Welding Society (AWS) has no standard for Flux cored Aluminum wire, here is a link to the standards page for you to double check if things change.
  2. The fact is that flux chemicals in common use for steel MIG welding just do not work for Aluminum. Aluminum is just too reactive with air.
  3. There have been some laboratory testing of fluxes that do work for Aluminum, however laboratory tests and a commercial application are two very different things. Why?
  4. The reason the process is difficult in the real world outside of a laboratory is that in the real world there are many things that need to be controlled. Aluminum is reactive and finding a chemical shield that can be used as a flux in MIG welding is a huge problem.
  5. The shielding chemicals that have been used in the lab are corrosive – not exactly what you want for your weld. They suck up water from the air, which means that real world storage of the flux would be problematic. Open the package and in a few minutes your welding wire is contaminated. And incorrect storage would mean your weld would be poor, porous and most likely fail.
  6. The chemicals that do work in the laboratory are environmentally a disaster. And who wants that.

here is a link to the article to have a read of:

If there is no such thing as flux core Aluminum MIG wire, what options do you have for welding Aluminum?

Can You Use ‘normal’ Flux Core Welding Wire?

The short answer is no, you can’t use steel based flux core wire in your FCAW welder to weld Aluminum. It just won’t work, you won’t get the join you’re expecting.

You may burn out your welder as the electricity – the Amps needed to weld Aluminum is more than a basic 90 Amp or 130 Amp welder is capable of generating. The splatter produced would be mind blowing, clog up your contact tip and could even short out your welder. And after that you’d have no weld or one that just failed.

No point trying that one.

Welding Aluminum Without Gas? What are your Options?


The only method out there that possibly uses no gas at all is soldering but even there, most of the methods you’ll find uses a propane gas torch to melt the solder material into and onto the joint.

The use of a soldering iron is limited – but at least there is no gas involved at all if you use one. Its application is limiting, as a soldering iron is not able to generate enough heat for a firm joint of any significant size.

The joint needs to be extremely clean as contaminants can cause your solder not to stick. Particularly with Aluminum as it is so reactive with air.

Soldering with a Torch

The main difference between soldering a joint with a flame torch and brazing is that in soldering, the solder – the filler material – melts at a lower temperature compared to brazing wire. The materials to be joined are heated but not melted and solder is flowed into a small gap between the metals to be joined.

Aluminum Flux Core Wire for Brazing

In brazing the filler material melts at a higher temperature but it is important to understand that the joints to be joined are heated but not melted.

Flux Core Aluminum welding wire used for brazing is designed for a different process to Flux Core Arc Welding. Brazing joins metals together but not by using electricity to melt the base metals and the filler materials.

Brazing Warming the joint

Brazing Flame Torch Warming the joint. Picture Credit: Lucas-Milhaupt

Commonly a gas flamed welding torch is used Not a MIG torch.

The flame is held near and around the joint to heat the Aluminum enough so the flux core Aluminum wire melts but not so much that the Aluminum itself melts.

Brazing Filler Flow

Brazing Filler Flow. Picture Credit: Lucas-Milhaupt

A brazed joint needs to be scrupulously clean, particularly if you are welding Aluminum. Filing or chemical cleaning may be needed particularly if the joint is dirty. The joints are brought very close together.

By close together I am talking about a gap of 0.0012 to 0.024 of an inch so that you can get sufficient flow of the filler material into the gap to make the join. And also for joint strength.

Finished brazed joint

Finished brazed joint. Picture Credit: Lucas-Milhaupt

Gasless Aluminum Welding wire, is there such a thing?

Outside of soldering with a soldering iron

and for the reasons above no.

Gas is needed to weld Aluminum whether it is in the brazing process where you use a torch head with flammable gas to heat the joint and flow the brazing filler into the joint.

or Argon gas is used to protect the joint as used in a MIG or for TIG welding.

Basically because of the reactive nature of Aluminum when it is melted in MIG welding it is all to easy to spoil your join with the contaminants in the air without some kind of protection while the weld is being made.

MIG Welding Aluminum

MIG Welding uses electricity and shielding gas which is often Argon to protect the joint from the air. The MIG melts the base metals. i.e. the metals to be joined and the filler material so that they all flow together and forms your join.

Welding Aluminum, Your Options are

1. The best option and the easiest option is; To get yourself a MIG welder that is up to the job for welding Aluminum and a spool gun. And what I mean by that is that you need a MIG capable of achieving the right heat level, a spool gun to feed solid Aluminum welding wire and Argon gas fed up to your weld.

2. Best and prettiest option is to use a TIG welder, if you are skilled in the art of TIG welding. You will get the best looking join, which is particularly good if the join is visible and it’s important that it looks good. It is a slow process and demands skill and practice. But I suspect that if you’re doing this search you’re no TIG welder.

3. The next possible option. Some have tried using a normal MIG gun and a Teflon liner. Argon gas is needed to shield the weld. However, a new clean Teflon liner is smooth and offers less friction for the soft Aluminum to slide through.

The torch head cable laid out as flat and level as possible so that you can get the best feed you can. And the tension rollers of your MIG’s wire feed adjusted so that it grips the Aluminum gently and doesn’t crush it as soon as it comes out the wire feed. Polarity changed for welding with Argon gas and solid Aluminum wire. And it is possible.

This 15 minute video takes you through the issues, and some of the solutions. Unfortunately it doesn’t show you a successful weld but it does show you what can happen and often does.

Tips for MIG Welding Aluminum without a Spool Gun

Video Credit: Weld.com

Aluminum is a soft metal and pushing it up from the wire feeder of the MIG through 10 foot of cable to the torch head often bends the Aluminum inside and then you get non existent or poor wire feed.

Birds Nest of Wire

Birds Nest of Wire

This next video 7 minute video not only covers the issues, it shows some welds. It’s a bit rough and ready but does show you how it can be done.

How to MIG Welding Aluminum without a Spool Gun

Video Credit: A21bravo

No Spool Gun Weld Results

No Spool Gun Weld Results

The welds aren’t pretty and will need grinding to smooth off but he got a weld.

4. If you’re desperate and have a stick welder to hand. Well, I found this video from WeldingTipsandTricks where he compares using a stick welder or a TIG welder with Aluminum flux stick rods if you find yourself in a tight spot and that is all the equipment you have available.

Again, works, but its not petty and there are issues with the joint with some porosity using the sticks.

Aluminum Stick Weld Porosity

Aluminum Stick Weld Porosity

Preheating helped.

Aluminum Stick Weld Preheat

Aluminum Stick Weld With Preheat

but if you are stuck in a jam it’s a way through.

Here is the complete just under 4 minute video to take a look at

Stick Welding Aluminum

Video credit: weldingtipsandtricks

To Close

The Unicorn of flux core Aluminum welding wire does not unfortunately exist, even if you want it now. I hope my article has shown you some of the options available for welding Aluminum and if you are interested in looking at some of the welders capable of MIG welding Aluminum, why not check out the Hobart Handler 140 or the Everlast iMIG articles I have on the site.


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