Welding is one of the most renowned and strongest joining processes performed on metals. Due to the high density of metal components, it is very difficult to create a permanent joint between two separate components unless you are welding them together, which is quite an easy process.
Today, we will be taking a brief look at a special type of welding method called TIG welding. It is an incredibly popular and useful welding process that is commonly performed on metals like aluminum and its alloys. If you frequently perform TIG welding aluminum, our tips and techniques today will surely help you.
Aluminum TIG Welding
First, let’s talk about aluminum TIG welding. TIG stands for tungsten inert gas, and as the name suggests, TIG welding requires shielding of an inert gas like argon. A weld is formed by melting a certain portion of the workpiece, which is possible because of the high temperature arc generated between the tungsten electrode and the workpiece.
The arc itself is generated by feeding the argon gas, which is carried through a nozzle to generate a precise welding torch. TIG welding is also highly popular because of its controlling parameters that can be easily controlled with the help of a foot pedal for accurate results.
Pros And Cons Of Aluminum TIG Welding
Here are some advantages and disadvantages of aluminum TIG welding which you must know before you get along with the process. While some of the advantages mentioned here will be great for your application, a few of its limitations cannot be ignored.
- You do not necessarily require a filler rod for aluminum TIG welding.
- Welding quality is very high.
- Due to the adjustability of the welding torch, all welding positions are possible.
- Suitable for a range of metals, including aluminum alloys.
- Perfect welding process for thin metals.
- No slag or spatter is generated throughout the process.
- The welding process is highly efficient.
- A large and heavy setup that is difficult to move.
- Cannot perform outdoors due to the effect of environmental factors.
- Metal needs to be cleaned completely beforehand.
- Comparatively slower welding process.
- Skilled operators are required.
Aluminum TIG Welding Tips
Now that you know some of the pros and cons and aluminum TIG welding, you might be reconsidering it for your applications. But, you should not worry as we have a handful of tips and techniques that will improve the results and help you along the way.
To perform perfect aluminum TIG welding, you need to go through our list of the tips and safety precautions provided in this article. Make sure you read the article until the end so that you don’t miss out on the important parts.
Practice Before Starting The Weld
All professional welders can confirm that welding is a one-way process. Due to the high intensity of current and extremely high welding temperatures, the changes made to the metal workpieces are permanent. Hence, you should take some time and practice the operation before you get started with the actual workpiece. You can perform the practice weld on some scrap workpieces that are not going to be useful later on.
A little practice beforehand will allow you to understand key differences between AC and DC welding techniques. Also, you can train yourself to generate the perfect bead so that your final workpiece looks attractive after you perform welding on it. The practice session also allows you to test the machine and verify whether it is working properly or not.
Technique For DC-TIG Welding Aluminum
TIG welding is quite an easy process once you get a hold of it. With a little bit of practice, you will be able to generate decent welding results even if you are just a beginner in the field. Here are some techniques that you should follow while performing DC-TIG aluminum welding.
1. Hand and Torch Placement
The hand and torch placement is a basic parameter of TIG welding that creates a large difference in the end results. You also need to control the hand movement as aluminum rapidly transfers the heat away from the welding portion, which makes it much more difficult.
The first thing you should do is hold the torch with a firm and secured grip. For that, you need to hold it from the base of your palm and control the trigger with the end of your finger.
While welding, the torch needs to be steady and in a forward-moving position at all times. For a proper field of view, you should also tilt the machine within 5 to 15 degrees backward.
Lastly, you need to take care of the distance between the torch and the workpiece. Generally, it should be equal to the diameter of tungsten and it should stay constant throughout the session.
2. Proper Movement of the Torch
Now that you know how to hold the torch at a correct position, let’s talk about the movement of the torch.
You should practice the movement a couple of times before turning on the machine to get an idea about the weight and balance of the torch. Once the machine is on, you will have to keep a light pressure on the device with a firm grip and slide it across the welding area in a steady motion.
You also need to move your entire hand instead of your fingers if you wish to cover more area without breaking the flow. This will help you to understand the motion of the torch and calibrate it with the motion of the filler rod.
3. Puddle Control
The puddle means the freshly welded portion of the metal. This includes molten metal created because of the high-temperature torch. The puddle is formed irrespective of whether you add filler material or not.
While welding aluminum, you will find a generous amount of puddle getting formed while moving the torch. As aluminum is a good conductor of heat, the puddle formation speeds up along with the process. Thus, you need to monitor it and manually control the foot pedal in case you find the puddle getting too hot.
At the end of the workpiece, there is generally a smaller surface area left for heat absorption. Thus, you will have to ease the foot pedal and maintain the puddle control until the end. But, losing too much current will cause the puddle to disappear, which might ruin the bead at the end.
4. Adding Filler Material
If you have practiced proper puddle control, you can safely introduce filler material while welding. The main factor in this process is consistency. You need to introduce a uniform amount of filler material as you go along with the weld.
First, you will have to establish a puddle before you can start depositing the filler material in the bead. Once you have started the puddle with a steady torch movement, you can start introducing the filler material to the weld. Keep in mind that filler rod needs to be precisely in a right angle configuration with the torch for proper deposition.
TIG Welding Safety
Safety should be your first priority while working with workshop tools and equipment. In the case of welding, there are a lot of safety parameters that you need to keep in mind so that you can avoid mishaps and accidents completely.
Here are some of the most important welding tips for aluminum TIG welding:
- Get an auto-darkening helmet before starting the welding process. TIG welding torch is very bright and easily allows you to see the process even though a completely dark see-through the helmet. This will prevent your eyes as well as your skin from any damage.
- High-quality gloves and leather aprons should be preferred while welding. Even a tiny piece of molten metal can cause serious damage if it comes in contact with your skin.
- If you are performing longer welding sessions every day, you might suffer from a lack of oxygen in your working space. A respirator is required in such cases to provide a sufficient supply of oxygen.
Necessary Precautions Before You Weld
Now that you are familiar with the necessary precautions you need to take while performing the welding process, let’s step back a little and talk about precautions that should be considered before you start the process. These precautions are equally important for your safety and performance.
- TIG welding can be performed with both DC as well as AC current. You need to make sure you are using the proper source for your present application to avoid damage to the workpiece.
- Even if your machine is capable of operating at a high power output, start with low power output and test the device before increasing the amperage.
- Before you start the welding torch, make sure you are holding the welding gun at the correct angle, as you will not be able to adjust the angle once the torch is active without damaging the workpiece.
- There are certain variants of tungsten gas available in the industry. To get the perfect welding performance, you need to connect your TIG welding machine with the correct type of tungsten supply.
Using The Right Materials
The components you are going to weld also require a fair bit of attention if you want to carry out a perfect welding session. These include the workpiece, welding components, and even a dedicated heat sink. Take a look at the following tips regarding using the right material for TIG welding.
- First of all, you need to clean the metal components so that they can provide the right surface for welding.
- If you are using TIG welding for aluminum, make sure you are using a pure tungsten rod as it is the most efficient option for the process.
- Apart from thoroughly cleaning the aluminum workpieces with a brush, you should try preheating the components so that the initial welding does not get affected by the cold surface of the metal.
- If you get a heat sink, you can prevent warping of the aluminum, which is ideal in most cases.
Perfect Welding Surface
You will be able to perform the welding more efficiently and productively if you perform it on the right surface. The primary requirements are to develop a clean, dry, and flat surface that does not allow vibrations and keeps the workpiece at an appropriate height.
Also, make sure your welding zone has proper grounding so that you can properly ground your machine before starting it. Having additional clamps, jigs and fixtures also help a lot to hold your workpiece firmly in a place.
TIG Welding (Butt Joints)
If you are performing butt joints on aluminum, you need to take additional care as aluminum can buckle and ruin the weld. Thus, you need a few tricks to perform the optimum butt joints on aluminum components.
For example, you can enhance the welding tacks by providing a slight angle to the torch. This will give you a clean joint surface to carry out the butt joint easily.
Also, this gives you some margin of error as the tack will hold the workpiece in place firmly while you follow the joint surface. Even if you miss a spot or a segment, you can simply stop and resume without any problem.
Using Foot Pedal or Hand Control For Manual Current Control
A TIG welding setup does not necessarily include a dedicated manual amperage control unit as it can be set digitally on the machine itself. But, it is inefficient to change the amperage every time you start the process. Also, it does not allow constant changes while the process is active.
To solve that, you should get a separate hand control or foot-controlled pedal. If you are not sitting at a table with your legs free on the ground, you can also go with a torch-mounted amperage-controlled unit. This will give you precise control over the welding performance as you can adjust the intensity of the welding torch on the go.
Also, it allows you to simultaneously manage the welding current intensity while you are performing the weld. Thus, you can reduce the intensity at a thinner part and increase where needed without losing focus on the torch.
How To Clean Aluminum
The first step of aluminum TIG welding is to get the aluminum components as clean as possible. Even slight debris or impurity on the surface can damage the weld and create a weak point on the joint which might result in an early failure.
Another important reason to get the component cleaned is the residue oxidized surface on the aluminum. This surface has a higher melting point as compared to the base aluminum metal surface. Thus, it generates a brittle welding joint which needs to be avoided.
Here’s how you can clean the aluminum components before welding:
- You should start by cleaning off the paint, grease, and oil present on the surface. This can be done by rubbing the surface with a solvent wipe. Any decent degreaser will remove the oil and grease whereas you might need paint thinner to remove the paint. You can also use acetone if the above solutions did not work.
- For the oxide layer, you will require a stainless steel brush. But, make sure that it has fine bristles. Instead of trying to remove the layer, coarse bristles might scratch the surface, giving you an uneven surface to work with.
- In the case of large workpieces, you will have to use chemical cleaning solutions as it is not possible to scrub the whole unit with a brush. You can use the acid bath or industry-standard aluminum cleaners to remove the oxide layer quickly.
When Should You Use AC Current
AC current in aluminum TIG welding should only be preferred if your workpiece is dirty and contains a large area of the oxidized surface. AC welding technique also introduces a little bit of cleaning on the workpiece, which cannot be obtained with the DC input. Hence, AC input is recommended if you are working with carbon-coated parts like engine parts or old and heavily oxidized scrap material.
AC current is also an ideal choice for joining two pieces of cast aluminum. As the casting process introduces a large amount of oxidation on the surface, the surface is harder to melt, especially by DC input. So, if you are preferring appearance and a good finish on your weld, you should use AC current.
Combination of AC and DC Welding
You can either use AC current or DC current while performing aluminum TIG welding. But, in some cases, it is preferable to use both to generate the best results. In most cases, it is needed for welding thicker jobs. Here’s how you can combine AC and DC welding:
- First, create a bevel between the edges of two components, so you get a V-shaped cavity.
- Now, carry out the DC welding to create a root bead in this area. This completely fills up the bottom portion of the V-shaped cavity.
- Now, clean the welded area to remove any excess oxidized surface.
- Lastly, you can make a cap weld using AC current. The AC current helps to scrub the contaminants from the root weld and the edges. Also, AC current weld gives a comparatively better finishing to the welded portion.
Today, we have discussed a handful of tips and techniques that are good to know if you indulge in aluminum TIG welding frequently. If your day-to-day professional job includes aluminum TIG welding, these tips are helpful for you.
Once you go through all of the techniques and safety precautions mentioned here, you will be able to carry out a safer and more precise TIG welding on aluminum. If you have any doubts regarding the steps mentioned here, you can reach us via the comment section.