Tig Welding Aluminum: A Step by Step Guide

Tungsten inert gas (TIG) welding is a popular and highly versatile welding process that is often used for welding aluminium and other non-ferrous metals. It is known for producing clean, high-quality welds with minimal defects and a polished appearance.

However, welding aluminium can be challenging due to its unique properties and the potential for defects such as porosity, slag inclusion, and undercutting. To produce the best possible welds, it is important to choose the right equipment and follow the appropriate procedures.

Tig Welding Aluminum: A Step-by-Step Guide

In this article, we will provide a step-by-step guide for TIG welding aluminium, including tips for selecting the right equipment and preparing for the welding process.

Step 1: Clean And Prep The Aluminium

The first step in TIG welding aluminium is to clean and prepare the parts to be welded. This includes removing any dirt, debris, or oxide build-up from the surface of the aluminium using a wire brush or grinder. It is important to remove these contaminants, as they can interfere with the welding process and produce defects in the weld.

After cleaning the aluminium, you should also check the fit and alignment of the parts to be welded. Proper fit and alignment are crucial for producing a strong, defect-free weld. Make any necessary adjustments to ensure that the parts are properly aligned before beginning the welding process.

Step 2: Set Up The Tig Welder

The next step is to set up the TIG welder according to the specific requirements for welding aluminium. This includes choosing the correct TIG welding machine and settings, selecting the appropriate shielding gas and filler material, and setting the amperage and travel speed.

Choosing the right TIG welding machine: When welding aluminium, it is important to use a machine that is specifically designed for TIG welding. A constant current (CC) welding machine, also known as a DC power source, is generally recommended for welding aluminium.

Selecting the appropriate shielding gas and filler material: The type of shielding gas and filler material you use can have a big impact on the quality of your welds. For aluminium, it is generally recommended to use an argon-based shielding gas and a pure aluminium filler material. It is important to follow the manufacturer’s recommendations for the specific type and flow rate of shielding gas to use.

Setting the amperage and travel speed: The amperage and travel speed are important factors that can affect the appearance and strength of the weld. For aluminium, a good starting point is to use an amperage of 20-30 amps for thin sheets, 40-80 amps for thicker sheets, and 80-120 amps for pipes or thicker materials. The travel speed should be adjusted according to the thickness of the material and the desired appearance of the weld.

Step 3: Begin The Weld

Once the TIG welder is set up and the aluminium is prepared, you are ready to begin the welding process. To initiate the arc, you will need to use a high-frequency start. This involves turning on the high-frequency current and touching the tungsten electrode to the workpiece to create the arc.

Once the arc is established, you should maintain a stable arc throughout the weld by adjusting the distance between the tungsten electrode and the workpiece as needed. It is important to avoid letting the arc wander or go out, as this can cause defects in the weld.

To control the weld pool and produce a smooth, continuous bead, you should use the correct travel angle and travel speed. The travel angle is the angle at which you hold the torch relative to the workpiece, and the travel speed is the speed at which you move the torch along the weld joint. It is generally recommended to use a travel angle of about 10-15 degrees and a travel speed that is consistent with the amperage and travel speed settings you have chosen.

Another important factor to consider when welding aluminium is overheating. Aluminium is a heat-sensitive metal, and it is easy to overheat it and cause warping or distortion. To avoid overheating, you should move the torch along the weld joint at a consistent speed and avoid dwelling in one spot for too long. You should also be careful not to allow the weld pool to cool too quickly, as this can lead to defects such as porosity and slag inclusion.

Step 4: Finish The Weld

Once you have completed the weld, you should gradually reduce the amperage and allow the weld pool to cool naturally. This will help to minimize the risk of defects and improve the overall appearance of the weld.

After the weld has cooled, you should inspect it for defects and make any necessary repairs. This may include grinding down any rough or uneven areas, filling in any porosity, or removing any slag inclusion.

FAQ’s

1- How Do You Tig Aluminium For Beginners?

TIG welding aluminium can be a challenging task for beginners, but with practice and the right technique, it is possible to achieve good results. Here are some tips for TIG welding aluminium as a beginner:

Practice on scrap pieces of aluminium before attempting to weld on your final project. This will allow you to get a feel for the welding process and make any necessary adjustments to your technique.

Use a lower amperage setting when starting. A lower amperage setting will allow you to better control the weld puddle and reduce the risk of burning through the material.

Use a consistent, smooth motion when welding. Avoid stopping and starting the weld as much as possible, as this can cause the weld to become cold and weak.

Use the right filler material and shielding gas for the aluminium you are welding. For most aluminium alloys, a pure argon shielding gas and an aluminium filler material are recommended.

Wear the appropriate personal protective equipment, including a welding helmet, gloves, and apron.

2- How Do You Weld Aluminium With A Tig?

To weld aluminium with a TIG welder, follow these steps:

Clean the aluminium thoroughly to remove any dirt, oil, or other contaminants that could affect the quality of the weld.

Set up your TIG welder and make sure you have the correct filler material and shielding gas. For most aluminium alloys, a pure argon shielding gas and an aluminium filler material are recommended.

Clamp the aluminium securely in place and make sure you have good access to the weld joint.

Place the TIG torch in your dominant hand and the filler material in your non-dominant hand.

Begin the weld by striking an arc on the aluminium and establishing the puddle.

Slowly add filler material to the puddle as needed, using a consistent, smooth motion to avoid stopping and starting the weld.

Use the torch to manipulate the puddle as needed to achieve the desired weld shape.

Once the weld is complete, allow the aluminium to cool before removing it from the clamp.

3- What Polarity Do You Tig Aluminium With?

When TIG welding aluminium, it is generally recommended to use direct current electrode negative (DCEN) polarity. This means that the electrode, or tungsten, is connected to the negative terminal of the power supply and the workpiece is connected to the positive terminal. Using DCEN polarity allows for better arc control and a more stable arc when welding aluminium.

4- Do You Weld On Ac Or Dc On Aluminium?

When TIG welding aluminium, it is generally recommended to use direct current (DC) rather than alternating current (AC). This is because DC typically provides better arc control and a more stable arc when welding aluminium, which can result in a stronger, higher-quality weld. Additionally, many TIG welders are not equipped to produce AC, so it may not be an option in some cases.

5- Do You Push Or Pull When Tig Welding Aluminium?

When TIG welding aluminium, it is generally recommended to push the torch rather than pull it. This is because pushing the torch allows you to better control the weld puddle and achieve a smoother, more consistent weld. When pushing the torch, you should hold the torch at a slight angle to the workpiece, with the tungsten pointing slightly ahead of the weld joint. This will allow you to see the weld

Conclusion

In summary, TIG welding aluminium is a highly skilled process that requires the right equipment and a careful approach. By following the steps outlined in this guide and practising your welding skills, you can produce high-quality welds on aluminium and other non-ferrous metals. With time and experience, you can become an expert TIG welder and take on even the most challenging welding projects.