Can You Weld Aluminum With Flux Core Wire?

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You're not alone if you're looking for flux core aluminum welding wire. A lot of people get confused about this topic. Some people even try to deceive others about it.

Gasless aluminum welding wire is a good option for a minor welding job. It can save you money on MIG welding gas and a spool gun.

But even if your welder is a flux-core-only model, it might not be your only option.

Let's find out what's real and the myth: Does aluminum flux core welding wire exist? And can you weld aluminum with a flux core welder?

So, Can You Weld Aluminum With Flux Core Wire? No - you can't weld aluminum with flux core wire. The flux-cored wire for aluminum GMAW is not available. This is a rumors that goes around every few years. AWS has no specification for aluminum flux-cored wires, and the chemicals used in other metal types don't work on aluminum.

However, there are some things that you need to keep in mind when doing so. In this blog post, we will discuss why there is no flux-core aluminum welding wire and some of the pros and cons of doing so.

Why No Flux Core Aluminum Welding Wire?

I don't think there is any flux-cored wire for aluminum GMAW. This is a rumor that seems to make the rounds every few years. AWS has no filler specification for aluminum flux-cored GMAW wires.

Some people say it is possible to make flux-cored wires for aluminum. They did this a long time ago in a lab. But we don't have fluxes for submerged arc welding (SAW) aluminum yet, even though they have been demonstrated.

Why don't you do it if you can weld aluminum with FCAW and SAW? For flux to work well when welding aluminum, it needs to be more chemically active than the metal. This isn't easy to do in a production setting, so many welders still use FCAW or SAW instead.

The problem is that the chemicals used in fluxes for carbon steels or stainless steels don't work for aluminum. Aluminum is very high on the electromotive force chart, so most elements and compounds are not effective fluxes. Carbon steel and stainless steel fluxes don't work for aluminum.

The fluxes that have been developed for aluminum have several properties that are not desirable.

First, they are very corrosive, so every bit of them must be removed from each weld before proceeding. Second, they are extremely hygroscopic (they absorb water from the air).

This means that you need to store them very carefully. If you do not follow these procedures, you will get a weld with many holes in it.

Last, fluxes are very bad for the environment. That is why the FCAW and SAW processes have never been commercialized for aluminum. Do these reasons seem similar to why SMAW is no longer used in most places for aluminum? They should because they are fundamentally the same.

Besides this, there are several problems with using FCAW aluminum wire. These include usability and quality issues.

Let's break down the problems with FCAW aluminum wire.

  • Hard to Feed:

Solid aluminum wire is soft and tricky to feed. It's tough to put it through a machine without it getting crushed or jammed. That's why you need a specialized drive system for feeding the wire through a flux core machine.

  • Poor Flux Properties:

Different types of welding use different kinds of flux. Fluxes designed for carbon or stainless steel welding don't work for aluminum welding, and fluxes used in soldering and Brazing aren't effective at the higher temperatures reached in arc welding.

Moreover, welders need to be careful with the fluxes they use. Some fluxes can be very corrosive and damage both the welder and the environment. Plus, these fluxes absorb water from the air, leading to poor weld quality and more spatters.

  • Nature of FCAW:

Welding on steel can create a lot of spatter. This is because the fluid nature of aluminum at welding temps would make the problem worse. The amount of molten material expelled from the weld would reduce weld quality and appearance.

In addition, aluminum wire is more expensive than steel wire. So it's not a good option for high-volume production.

What Are The Alternatives To Flux Core Welding For Aluminum Joining?

Many welders who want to join aluminum must first decide on the welding process they want to use. Flux core, TIG, MIG, and even stick welding are all viable options for joining aluminum. This article explores the benefits of using flux core welding alternatives for aluminum joining.

  • MIG Welding

If you want to weld with a spool gun, you need a welder that can handle it. But if your welder is not spool gun ready, or you want to save some money, try MIG welding aluminum without a spool gun. You might find out if your machine can buy wire and liners. It might be worth the time and patience when the results are surprising!

  • TIG Welding

There are different types of welders. Some use a shield of pure Argon gas to create the nicest welds. Remember that it will take some practice to use a TIG welder. This type of welder is best for minor projects. In a pinch, you can use a DC TIG welder along with flux-coated stick welding rods to get the job done.

  • Stick Welding

An alternative is to use a stick welder with flux-coated welding rods.

  • Soldering/Brazing

Soldering and Brazing are processes that use heat to melt the filler material. It is not the base metal. This is different than Arc welding, which can deform metals at high temperatures.

840 F is the line for when you solder and braze. If it's below 840 degrees, you'll solder it. If it's above 840 degrees, then you'll braze. You can use filler if holes between the metal pieces need to be fixed. Or you use a filler rod to join the pieces together.

For joining decent aluminum down to around 1/8" ( 3mm), stick or wire welding is good for welding and Brazing. For thinner material, like sheet metal, you can solder up to about 7-8 oz of copper (.028")

The heat range for soldering is about 536F to 877 F, with 750 F being the most common. For Brazing, it's 538F-932F, with 750 or 800 F being the most popular for thicker materials.

What Wire Do You Use To Weld Aluminum?

The two most popular sizes are .030 and .035 in. diameter aluminum wire.

Both sizes work equally well with the proper machine settings.

Using a .030 in. wire will give you a more stable arc and better bead contour, especially vertical or overhead welding applications.

The .035 in. wire is usually used for general purpose welding of aluminum, as it provides a little more penetration, but it can be more difficult to start and control.

Whatever size you choose, make sure the wire you're using is specifically for welding aluminum.

Some people use stainless steel or other electrodes that contain alloys other than aluminum and will produce inferior results.

Aluminum electrodes come in a standard .030 and .035 in. diameter.

Another popular size for aluminum welding is .045 in., which can be used when more penetration and fewer spatters are desired, such as with heavy section work or fillet welds on thicker material.

What Metals Can You Weld With Flux Core?

Flux core is a type of welding wire that has a coating of flux along the length of the wire, so it can be used to produce welds from an automatic welder. Flux is generally made up of borax and other materials. Flux core welding wires come in different levels: basic, general-purpose, and high-strength.

Metals welded with flux core include stainless steel, nickel alloys, and some carbon steel alloys. Flux core welding is especially effective for joining these metals together because the flux coating on the wire helps protect the weld from corrosion.

Flux core welding can join many different types of metals together because the wire coating protects the weld from corrosion. For example, stainless steel is very strong but resistant to corrosion; it can therefore be joined with other metals using flux-cored welding wire, like carbon steel.

What Is The Difference Between Solid Wire And Flux Core?

Solid wire can be used to make welds without using an automatic welder; it only requires a welding torch. The flux-cored wire must be used with an automatic welder because shielding gas (usually argon) is applied through the automatic welder. Flux-cored wire can be used for different welding types of metals; it is most commonly used with steel and stainless steel.

The flux that coats the wire helps protect the weld from erosion, which may occur on the surface due to corrosion or high temperatures. The flux coating also produces slag once the molten metal has solidified; this can be more easily removed than the molten metal that does not have a flux coating.

Solid and flux core welding wires (also known as self-shielded flux-cored) can be used to weld steel and stainless steel together. Solid wires do not require an automatic welder as flux-cored wires do; the user only needs a welding torch to make solid wire welds.

MIG (shielded metal arc) welding is done by feeding one electrode into the power source while feeding another electrode through an automatic welder. This second electrode is usually made out of flux-cored wire. The molten metal and flux produced by the wire are then protected from atmospheric gases and contamination by a covering of inert gas.

Self-shielded welding wire, also known as self-shielded flux-cored welding wire, uses a special coating that prevents atmospheric contamination when it is in use. This provision allows it to be used in all positions, including vertical, overhead, or even beneath the surface of the material being welded.

Flux core welding wire is sometimes used with gas shielded arc welding processes. Flux-cored wires are sometimes chosen for TIG (inert tungsten gas) welding because they do not contaminate the tungsten electrode needed to start the arc.

Moreover, flux-cored wire is also used more commonly with automatic welding processes than manual welding processes. This is because a shielding gas feed is not necessary when using flux core wires on an automatic welder; a covering of inert gas is already included in the flux coating that covers the wire.


In conclusion, flux core wire is not suitable for welding aluminum. Aluminum welds require a constant feed of filler material in addition to a shielding gas to protect the weld pool from oxygen, and flux core wire does not emit any extra material.

Don't risk damaging your machine by weld aluminum with flux core wire. Instead, invest in aluminum wire for all of your welding needs.

Last Updated on February 9, 2022 by weldinghubs

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