Last updated on June 21st, 2023
TIG welding aka GTAW (Gas Tungsten Arc Welding) is a popular and renowned welding technique that is very effective when it comes to welding Aluminum. It provides you with clean and precise results.
If you get the equipment right and follow a proper process, you will be able to make strong, durable, and aesthetically appealing welds on aluminum.
When you are planning on using a TIG welder on aluminum, the most important step is setting up the welder itself.
Aluminum is a lightweight and soft metal that has a low melting point which makes it challenging to weld as compared to other metals, especially because of controlling heat input and dealing with the oxide layer.
It will include choosing the right equipment, adjusting the settings, and ensuring a safe environment.
Whether you are an occasional user or a beginner trying to learn TIG welding on aluminum, this comprehensive guide can help you achieve successful results.
Contents
Setting Up TIG Welder for Aluminum
Setting up the TIG welder for Aluminum will require you to go through the following steps:
- Choosing the Right Equipment (Right Type of TIG Welder)
- Selecting the Right Tungsten Electrode
- Cleaning the Aluminum Workpiece
- Choosing the Right Gas & Connecting the Gas Supply
- Adjusting the Amperage
- Adjusting the Alternating Current Balance Control
- Adjusting the Frequency
- Assembling the Equipment
- Choosing the Right Filler Material
- Practicing the Proper Technique
After going through all of these steps, you will be able to get clean, precise, and beautiful welds on aluminum.
Let’s dive into the details of these steps.
Related: How to Use a TIG Welder?
1. Choosing the Right Equipment
There are various types of TIG welders available in the market, some of which come with AC capability while others don’t have it. For welding aluminum, you will need a welder with Alternating Current capability.
The reason is that Aluminum forms an oxide layer on the top, which cannot be cleaned permanently. As soon as you brush it away, it reforms which render the Direct Current welding method helpless.
So, with Alternating Current, you will be able to break through the oxide layer and create a strong weld.
You can choose to purchase the welder that comes with an AC/DC switch or one that is specifically designed for aluminum welding.
Another thing you need to keep in mind while selecting the right TIG welder for aluminum is to make sure that it has a wide amperage range.
Aluminum welding is complex and requires a higher amperage range than steel. So, for a thicker sheet of aluminum, you will need a much higher amperage range.
2. Selecting the Right Tungsten Electrode
A pure tungsten electrode is highly recommended for aluminum welding but you can choose to go with a zirconiated tungsten electrode as well. If you don’t recognize them, then you can use the color code scheme to identify them.
The pure tungsten electrode has a green color code while the zirconiated electrode has a white color code.
Other than the type of electrode, its thickness or diameter is also of crucial importance. The thickness mainly depends on the amperage you will be using. A thicker electrode is capable of handling more amperage as compared to a thinner one.
Since aluminum requires higher amperage, you will need an electrode that has more diameter than conventional ones.
As a rule of thumb, you should use a tungsten electrode that is one size smaller than the thickness of an aluminum plate.
So, if you are welding a 1/8-inch aluminum plate, you should use a 3/32-inch electrode.
It is also important to sharpen the tip of the electrode to get a cleaner arc and ensure a more precise weld.
3. Cleaning the Aluminum Workpiece
The next step is very important because it will determine the quality of the weld you will get. If you don’t get this step right, despite having an amazing technique, you might not get desired results.
You need to properly clean the aluminum workpiece to remove any dirt, grease, or oxide layer.
Yes, aluminum generates an oxide layer that tends to be of a dull silver color. The melting point of this layer is three times the melting point of base metal.
You can use acetone and a cleaning brush to get the job done. I recommend that you use a specialized stainless steel brush that is designated for aluminum to clean the surface. You can also use a carbide cutter.
Using acetone is quite helpful and ensures that you get clean and beautiful welds.
4. Choosing the Right Gas & Connecting the Gas Supply
Argon is preferred for aluminum welding as it is perfectly suited for the job. This gas ensures better cleaning and shielding effect while working on aluminum.
Not only this, argon is easily available, most widely used, and provides the best arc stability that allows even beginners to get high-quality welds with aluminum.
The flow rate of the gas is adjusted to maintain a consistent arc length and to protect the weld pool.
Connect the argon gas supply with the welder, and set the flow around 15-20 cubic feet per hour. You can increase the gas flow based on the amperage you are using.
5. Adjusting the Amperage
One of the most important steps that will dictate the whole welding process. You have to set several preferences on the machine to get the job done right.
Let’s start with amperage. The amperage of the welder depends on the thickness of the aluminum. As a general rule. 1 amp per 0.001 inches of aluminum thickness is a good point.
For example, if you are welding an aluminum sheet that has 1/8 inch thickness, you will need to set the amperage at 125 amps. However, you may need to change it depending on the specific requirement.
However, when you reach a thickness of ¼ inch, the rule begins to change. At that point, the change in amperage is not what it was before as not much amperage is needed. You can weld a 3/8 inch thick aluminum plate with just a 280 amp source.
Adding to this, the amperage can also vary depending on the type of joint you are trying to create. For example, when you are creating a T-joint, the heat flow can go in three directions, which means that it will require more heat input.
However, when you are creating a butt joint, the heat can only go in two directions, so you will need less heat input.
6. Adjust the Alternating Current Balance Control
The balance of the Alternating Current will control the amount of cleaning versus penetration. The cleaning will be from EP (Electrode Positive) and the penetration is (Electrode Negative).
So, EN is responsible for welding while EP is responsible for the removal of the oxide layer. You can adjust the ratio of the two depending on the welding requirements.
For the starting point, you can set the balance at 70% EN and 30% EP. The modern equipment allows you to adjust the balance in real-time.
However, the older TIG welders balanced it on a 50-50 ratio which made even TIG welding aluminum a bit difficult but now with modern GTAW equipment, you can adjust the balance as per your observations of the weld pool.
As an example, when you are dealing with material that has been exposed very much and has a thicker oxide layer, you can turn the EP up and EN down to increase the cleaning. However, this will make it a bit difficult to control the arc.
You need to learn how to maintain proper balance by practicing.
7. Adjusting the Frequency
To control the arc and heat input, you will also need to set the frequency limit on the welder.
The output frequency refers to how many times per second the power source will switch polarity. The modern equipment has a default frequency set of 120 hertz.
Higher frequency means a more stable arc, which means better control in tight spaces.
So, you can increase the frequency when you are welding in tight spaces and require more directional control.
However, when you need a wider arc, you can reduce the AC output frequency. You can lower it to 80-90 Hz.
The frequency for aluminum welding can be set between 120-200 HZ for better arc control and more focused heat.
So, when you need higher accuracy, you can even go as high as 250 Hz, to prevent heating up a large area or burning through.
Once you have adjusted these settings, your welding setup process is almost complete.
8. Assembling the Equipment
Before starting the welding process, one final thing you have to do is assemble the torch.
To assemble the TIG torch, you have to adjust the chosen electrode, the appropriate collet, and the gas nozzle with a large diameter.
Assembling them and attaching them to the gas supply, will set up your TIG welder for aluminum welding.
9. Choosing the Right Filler Material
The selection of filler material is also crucial in determining the final quality of the weld. When welding aluminum, you have many options available as filler material.
The most commonly used filler material for aluminum is 4043 and 5356. 4043 is more suitable for welding aluminum alloys and provides good corrosion resistance.
The 5356 is recommended for aluminum alloys that have high tensile strength.
You must also ensure that the filler material is clean and free from any contaminants.
If the filler material has any contaminants in it, it can lead to porosity or contamination in the weld, which will not only ruin the quality of the weld but might also lead to cracking.
10. Practicing the Proper Technique
You need to practice the torch angle, foot pedal control, and filling process as much as you can to get it right with aluminum welding.
It is as important as setting up the TIG welder. You must know that TIG welder has a bit of a learning curve and without the right technique, the whole setup is of no use.
Hold the torch angle at 10-15 degrees away from the direction you are moving the torch in. This will help you maintain a tight arc length and avoid excessive heat input.
Adding to this, the foot pedal allows you to manage the amperage and heat control effectively and efficiently. You will be able to focus your hands on stability while your feet control the amperage.
Similarly, adding the filler material also requires proper technique and angle. Doing it wrong will lead to crater formation which can cause cracking.
Importance of Safety
TIG welding is an accurate and precise welding process that has no spatter but it is still important to wear protective equipment to prevent any risk of injury or harm.
So, you must wear a welding helmet or safety goggles, welding apparel, gloves, and leather shoes while using the welder machine.
Exposing skin to the welding process can be quite harmful. Also, welding with bare feet or hands can also risk electrocution.
You must prioritize your safety above all while welding and wear protective equipment at all times.
Also: How to Set Up Tig Welder for Stainless Steel? Ultimate Guide
Frequently Asked Questions
What settings do I use to TIG weld aluminum?
There is a wide range of settings you can use for welding aluminum. The exact settings will depend on the thickness of the material, the nature of the weld, and the nature of the joint you are welding. You can read the above guide for more details.
What is the best frequency of TIG welding aluminum?
The ideal frequency is between 120-200 Hz when welding with aluminum. The higher frequency provides you with more arc control and more focused heat. You can increase to get even higher accuracy.
Do you TIG weld aluminum with DC or AC settings?
Aluminum is welded with AC settings, and it is not possible to weld aluminum with DC settings. Aluminum forms an oxide layer continuously which needs to be broken through to weld the base metal inside. That requires AC settings.
What gas is used for TIG welding aluminum?
Argon is preferred for welding aluminum. It is the most widely used gas and has the best compatibility when it comes to aluminum. It provides better cleaning action and arc stability.
Related: What is a TIG Welder?
Wrapping Up!
To sum it all up, TIG welders require specific settings for dealing with aluminum. So, you need to set up a TIG welder with appropriate amperage, frequency, and balance before you can use it on aluminum.
The welding process requires a different set of parameters for welding different metals and each metal requires its own settings.
The above guide provides you with all the details you need on how to set up a TIG welder for aluminum. If you are a beginner, the guide will help you practice welding techniques and make them perfect.
By following the steps mentioned above, you will be able to create clean, strong, and high-quality welds.
If you have any questions, you can drop them in the comments section below and I will get back to you.
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