Can All and Any TIG Welders Weld Aluminum?


The first thing we need to do is get on the same page with what we mean by “welders.” Sometimes we mean the machines that we use. Sometimes we mean the person who is using that machine. In this article, we’ll be focusing on the welding plant themselves. 

Can all and any TIG welders weld aluminum? TIG welding is the primary method used to weld aluminum. Any TIG welder “can” weld aluminum, but there are several factors that will influence the ease, quality, and appearance of your project. Of these, the current is by far the most important.

While any TIG welder can weld Aluminum, not all TIG welders are created equal. We all know that this statement applies equally to the machines and the people who operate them, but again, we’re only talking about the welding plant here. Read on to learn more about how to set yourself up for success when you’re welding Aluminum with a TIG machine.

Not All TIG Welders Are Created Equal

Choosing the right machine and knowing how to set it up can make it easy for a rookie to turn out welds that look top-notch. If the welding plant you have lacks specific options, there are things you can do to make the best of your situation, but even a seasoned pro will have to work harder to get the same results.

Factors That Will Influence Welding Aluminum with a TIG Welder

Many factors will impact your project. The first thing we need to do is identify what they are:

  • Current: Alternating current (AC) is the preferred setting for welding aluminum. If your machine doesn’t have AC settings, you can still weld Aluminum, but you’ll need to set up your DC welder the right way.
  • Frequency: This determines the output of your machine.
  • Balance: This determines the balance between the direct current + (DC+) and direct current – (DC-) portions of your current’s flow on an AC setting. The positive part provides an important cleaning function. The negative part gives you your heat penetration.
  • Amperage: This determines the penetration of your weld. TIG machines have foot pedals that allow experienced operators to fine-tune the amperage while they work.
  • Pulse: This is a feature that some machines offer. It helps to prevent burn through by supplying the current in pulses rather than as a steady stream.

If the machine you are working with gives you access to and control over all of these factors, then getting quality TIG welds on Aluminum is as simple as setting the machine up for the job.

If your machine doesn’t give you control over any of these factors, then there are still ways to get the job done. Knowing how to get the best set-up available to you will go a long way towards making your life easy and your welds pretty.

How to TIG Weld Aluminum With AC

When your TIG machine has an AC/DC switch, AC is the way to go for welding aluminum. One of the things that makes welding aluminum different than welding steel is Aluminum’s oxide layer. 

Aluminum oxide forms on the surface of all aluminum alloys. It’s a result of the metal being exposed to the atmosphere, so the surface of every piece of Aluminum is going to be aluminum oxide. Aluminum oxide becomes an issue for welders because aluminum oxide has a much higher melting point (3600°F) compared to the Aluminum underneath it (1200°F).

The alternating current of AC welding will penetrate the Aluminum with heat to give you a strong bond. At the same time, it will lift away or clean the aluminum oxide layer above it. 

Using this mode isn’t the fastest way to weld, but it will give you the quality joints and professional appearance that you’re looking for when welding Aluminum.

Setting Up Your AC TIG Welder

Once you’ve switched your machine to AC, there is a straightforward checklist to the rest of the set-up:

  1. Set the Frequency – Set your frequency at 60 Hz. This frequency will get your machine ready to run at an output that is comparable to an old-school transformer machine.
  2. Set the Balance – Set your balance at 30. With a balance at 30, your machine will run at 30% electrode positive (the flow that cleans aluminum oxide) and 70% electrode negative (the flow that gives you your heat penetration.
  3. Set the Amperage – Set your amperage at 200. This value is a good starting point. You can adjust as necessary depending on the thickness and alloy of the Aluminum that you’re working with.
  4. Adjust the Gas Flow – Open up the tank(s) and set the regulator.

If you need some additional help getting set up for your job, the guys at Weld.com will walk you through it step by step.

Pulse is another setting that you’ll want to consider when you’re setting up your TIG machine to weld aluminum. There’s a lot to cover on the subject of how to make pulse work for you, whether you’re working in AC or DC. The guys at Weld.com have put together some helpful tips for you here.  

Let’s take a look at how to set yourself up for success if AC isn’t an option.

How to TIG Weld Aluminum With DC

As we discussed above, AC is the preferred setting for TIG welding aluminum. It will give you the ability to work on any aluminum alloy no matter the condition it is in. It works with any filler type, and it works best with your standard gas mixtures.

With all of that in mind, you can still get quality welds on Aluminum with a TIG machine running direct current. In fact, “Mr. TIG” at Weld.com recommends the DC setting for specific situations. 

He’s put together a great video that walks you through the details. Using his “ideal” situations for TIG welding aluminum on DC as a starting point gives us a good starting point for putting together a plan that will make the most of what you have when AC isn’t an option.

What You Need to Know About Setting Up to TIG Weld Aluminum With DC

Getting quality welds on Aluminum with a TIG machine running in DC mode can be challenging. Making them pretty can be even more robust, but if you start with these “ideals” in mind, you’ll have a way to make adjustments that set you up for success.

There are several factors to consider:

  1. Thickness: The ideal scenario for TIG welding aluminum on DC involves materials of ¼” thickness or greater. If you have to do a job in DC with thinner materials, you will have to be careful not to boil the Aluminum. Doing so will give you burn-throughs and result in weak or ugly welds.
  2. Alloy: The ideal scenario for TIG welding aluminum on DC involves 6061 alloy and 4043 filler rods. You can also get pretty good results on the 1100 series (pure Aluminum) and 2219 specialty alloy. 5356 filler rods will make it almost impossible to get pretty welds.
  3. Amperage: Mr. TIG recommends starting at 180 amps or less. You might need to adjust this setting to fit the thickness of your material, the condition it is in, and the alloys you’re working with.
  4. Gas: Mr. TIG recommends using 100% helium. Anything else is going to make it a lot harder to get the good weld strength and good looks that you want.

When you’re forced to use anything other than the best tool for the job, it can be frustrating. But sometimes budgets, emergencies, or other circumstances beyond our control mean that we have to do the best we can with what we have.

If all you have is a TIG machine with DC and you have to make a repair or get a fabrication project done, you can still make it happen. With a little bit of trial and error, a lot of patience, and the calming, cleansing effect of deep breathing, you can get it done.

The Conclusion

If you’re shopping for a new machine and you know that you’ll be working on a variety of materials or that Aluminum will be the primary material you work with, you have to get a machine with AC capabilities. There are just no two ways about it!

If you don’t work with Aluminum often, then the cost of a machine with AC capabilities might not be justified. The information above will help you get through a one-time job and back to your routine.

If you’re out in the field and have to make something happen with what you have available, then whatever you have will be enough if you follow the recommendations we’ve laid out above.

Alexander Berk

A bit about myself: I am a certified international welding engineer (IWE) who worked in different welding projects for TIG, MIG, MAG, and Resistance Spot welding. Most recently as a Process Engineer for Laser and TIG welding processes. To address some of the questions I frequently got asked or was wondering myself during my job, I started this blog. It has become a bit of a pet project, as I want to learn more about the details about welding. I sincerely hope it will help you to improve your welding results as much as it did improve mine.

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