The Ultimate Guide to Aluminum Welding Machines: How to Choose the Right One
Welding aluminum is not as simple as other metals. It is because of its distinct properties. Welders need to overcome several challenges to achieve a perfect weld.
That’s the reason a normal welding machine is not suitable for welding aluminum. It needs a dedicated aluminum welding machine. And that’s what we will be discussing in this article.
We will explain the challenges of welding aluminum, different types of aluminum welding processes, and how to select the right aluminum welding machine.
Introduction: Why Aluminum Welding is Unique
The first challenge in welding aluminum is its high thermal conductivity. Its thermal conductivity is 237 W/(m·K), which is five times more than that of Iron. That said, it can conduct heat five times quicker and creates the biggest challenge for welders.
Due to high conductivity, the heat travels away from the area to be welded. It brings the surrounding area under heat stress. Which could result in the deformation of the whole material, warping, and cracks. It also affects the properties of the metal.
The second challenge for welding aluminum is the low melting point. Which means it could melt easily compared to other metals. If you give excessive heat, it will melt more area than the required one and even pass through the metal.
Thus, controlling heat is extremely difficult in aluminum welding, and if you don’t do it, it will badly affect the weld quality.
Aluminum is also known for developing an oxide layer over time. It is thin but extremely hard and durable. It has a higher melting point than aluminum itself. Before welding aluminum, it is necessary to get rid of this layer. Otherwise, it will mix in the weld pool and create weak joints and inclusions.
Last but not least is the porosity. When aluminum is in the molten form, it is capable of absorbing hydrogen and other gases. And when it cools down, the solubility of these gases decreases, and they tend to leave the metal. Due to this process, the gases come out and create pores in the metal, which translates to weak joints and leads to weld failure.
Because of all the above reasons, standard welding isn’t sufficient for aluminum welding. It requires something special, a dedicated aluminum welding machine that can overcome these challenges and ensure perfect welds.
Types of Aluminum Welding Machines: TIG vs. MIG vs. Multi-Process
When welders need to weld aluminum, they have three common choices: TIG, MIG, and Multi-process welders. All these welding methods can work on metal, but the results they offer are different. That said, welders need to choose the right welding process according to the application.
TIG (GTAW) Machines
TIG (Tungsten Inert Gas) is one of the most preferred processes for welding aluminum. The primary reason is that it offers exceptional weld quality that not only looks aesthetically pleasing but is also strong enough. Secondly, it can overcome certain aluminum welding challenges.
The welding process is capable of dealing with the oxide layer, which is great. Even if you have pre-treated aluminum and removed the layer, there are still chances of the oxide remaining. But if you are using TIG welding, you don’t have to worry whether the oxide layer is removed or not.
When a TIG welder is used for welding aluminum, it must be AC (Alternating Current). AC TIG welding can break down the oxide layer. When it changes the polarity multiple times in a short interval, it goes through the oxide layers and welds aluminum without any issues.
Welders need to maintain the AC balance, something which ensures cleaning action and penetration. It represents the ratio of Electrode Positive (EP) and Electrode Negative (EN) half cycles.
The Electrode Positive (EP) is the cleaning cycle. In which the current flows from the aluminum metal or workpiece to the tungsten electrode. Due to heavy bombardment of electrons, the oxide layer is physically removed.
The second half cycle, Electrode Negative (EN), is responsible for penetration. In this cycle, the current flows from the electrode to the material. It concentrates the heat on the working piece and creates the weld pool without any hassle.
For excellent results, a welder needs to create a balance between the EN and EP cycles. If you want more cleaning action, you need a lower balance setting, which means a higher EP half-cycle. And for better penetration, a more EN half-cycle is required.
Secondly, welders need to pay attention to the arc initiation. For excellent weld quality, the welder should have a high-frequency arc start. It allows the welder to initiate the arc without physically touching the metal.The arc is started before the electrode reaches the metal surface. That said, the chances of contamination are greatly reduced.
High frequency also helps with creating arc stability. It gives more control to the welder and ensures better weld quality.
TIG is definitely a good option for aluminum welding. Because of extreme precision and incredible weld quality, it works pretty well. It is ideal for applications where aesthetics and weld quality matter, such as the aerospace and automotive industries.
However, mastering TIG welding is not easy. It requires years of expertise and experience because the welder needs to use both hands. Exceptional skills and practice are required to achieve immaculate welds.
Moreover, the AC TIG welding machine is more expensive than other options. And the welding speed is also slower. It is great for thin materials, but not suited for thick aluminum pieces.
MIG (GMAW) with Spool Gun
MIG (Metal Inert Gas) is another welding process used for welding aluminum. It is preferred for welding aluminum at high speed. It works exceptionally well for thick materials.
Often, welders pick MIG for welding aluminum, and it’s a go-to process for many applications. The reason behind this is the ease. MIG welding is known for hassle-free welding. Because of its automatic wire feeding and one-hand welding, it is preferred. Even beginner welders can achieve perfection with this welding process.
MIG is suitable for thick aluminum pieces. It’s because it can offer more heat input to melt thick materials quickly. Now, you might think that the high heat could ruin the material because aluminum has high thermal conductivity. The material could bend, distort, or crack, and the surrounding area could be affected.
But the truth is that even though it offers high heat, it’s also a fast process, so the torch moves faster and does not allow the heat to travel far and wide. Thus, the fast speed balances high heat input, making it suitable to weld thick aluminum sheets or pieces. Welders need high amperage and high speed to control heat.
MIG can weld aluminum, but there are some considerations. The biggest problem with MIG is the wire feeding delays because of the long path. It’s not an issue if you are welding other materials. But with aluminum, the wire feeding must be fast.
To solve wire feeding issues, welders can go with a spool gun. It’s a special MIG welding gun that has a spool mounted on it. It shortens the wire feeding paths, eliminates any delays, and ensures smooth feeding. However, it also increases the weight of the welding gun.
MIG welding also uses a shielding gas. Normally, it’s a mixture of gases. But for aluminum, you need 100% Argon. Even though it’s expensive, it is required for optimal weld quality. When you use pure Argon, it protects the weld pool from the contaminants in the air. It reduces the chances of porosity. Thus, the final joint is strong.
You can use MIG for welding aluminum in mass manufacturing. It offers excellent speed and productivity. But do not expect exceptional weld quality from TIG.
Multi-Process Welders
Multi-process welders can be used for more than one welding process. They are meant to be used for a wide variety of applications. Some people opt for multi-process welders because they are versatile.
You can do aluminum welding with a multi-process welder, but only if it can do the required welding process and features.
To work on aluminum, the multi-process welder should be capable of doing AC TIG welding. It is necessary for excellent weld quality, and we have already discussed the reasons. The problem is that most multi-process welders have only DC TIG welding. For AC TIG welding, you need to go for a separate TIG welder. But if your multi-process welder can do AC TIG, it can work on aluminum.
Secondly, the high-frequency feature is also important to start the arc without touching the metal. It is necessary to prevent contamination.
And if you are going for MIG in the multi-process welder, just make sure it has the spool gun. The second option could be a push-pull gun. It is an extra motor in the gun to pull the wire. It makes wire feeding faster and hassle-free without putting extra weight on the welder’s hand.
Keep in mind that most multi-process welders are not as good as separate welders. There could be a compromise in the performance or quality. And if you go with a very high-end multi-process welder, it will be extremely expensive compared to buying a separate specialized aluminum welding machine.
Multi-process welders are suitable for normal aluminum welding jobs, DIY, repairs, etc. For exceptional quality, it is recommended to go with a MIG or TIG welder.
Key Features to Look for in an Aluminum Welding Machine
While buying an aluminum welding machine, you need to look at several important factors and features to ensure it is the right welder for the purpose.
Here’s what to consider.
Power & Output
A lower-power welding machine is suitable for thin materials, and a high-power machine is made for thick materials. Thus, the power output defines the capability of a welding machine and what materials it can work with.
When looking at the voltage, 230V is something suitable for both thin and thick materials and most jobs. It can generate enough power. A 120V machine can work in thin materials because of the power limitations.
The next important thing to consider is the amperage. For aluminum welding, the minimum is 200A. If you want to cater to a wider range of jobs, go with 250A welders. It gives you the power to work on small to large-scale projects.
The second important thing is the duty cycle. It is the percentage that a welder can weld at their maximum amperage for a 10-minute period. That said, if the duty cycle of a 250A welder is 40%, it means you can weld at 250A for four minutes straight out of 10 minutes. Which means if you want to work on large-scale projects, the duty cycle must be higher so that you can work without any interruption.
AC/DC Capability
If you are using a TIG welder, then AC/DC matters. You need AC TIG welding to weld aluminum. It is necessary to break through the oxide layer and penetrate into the aluminum to create a weld pool. It is the best option for aluminum welding.
Even if you have a multi-process welder, make sure it has AC TIG. Otherwise, you will have to use MIG.
Spool Gun Compatibility & Included
For MIG welders, a spool gun is an essential component. You can’t weld aluminum with a normal MIG gun. It will feed the wire too slowly because of the long path. Eventually, you will have poor-quality welds.
A spool gun offers better speed of the wire. It is pretty smooth and reliable, perfect for aluminum welding. If the spool gun is already included with the machine, that’s great. If not, make sure the machine is compatible with it so that you can buy it separately.
Pulse Functionality
For aluminum welding, pulse functionality is a good option. It allows the welder to control heat and reduce the heat-affected zone.
The pulse function offers high peak current but only for a short period. This high current creates enough heat to melt the material. However, it is for a short instance, so the heat does not travel to a wider area.
In pulse MIG welders, this function quickly melts the wire with high current. Moreover, there is a background current, which always remains there to keep the arc. It offers the welder better heat control and weld quality. It can even weld thin materials.
When it comes to pulse TIG, the function is equally beneficial. It helps welders precisely control the heat and get better weld quality.
Controls & User Interface
In general, the machine should have simple controls and a user interface. It makes it beginner-friendly.
Beginners can opt for machines with basic controls, displays, and beginner-friendly features, such as the Synergic mode in MIG. It automatically controls the wire feed and voltage according to the material, thickness, and other factors.
As a professional, you should look for advanced options. You need more control for excellent results. You can look for AC balance, pulse mode, high-frequency arc start, etc. The more options you have, the better it is.
Top Applications: Matching the Machine to Your Project
When you want to weld aluminum, it is important to select the right welding process according to the use case or application. Let’s give a quick idea of where to use what.
Auto Repair & Restoration
In the automotive industry, TIG welding is the preferred option. It offers exceptionally clean welds. It can precisely weld delicate objects and ensure an excellent aesthetic finish.
For auto repairs or restorations, AC TIG welding is used. It not only offers high-quality welds but also incredible strength.
Marine & Boat Fabrication
Both MIG and TIG are useful for marine and boat fabrication.
If you want exceptional strength while keeping the aesthetic appeal, TIG welding is the right choice. It is great for intricate components and thin materials.
For thicker materials, MIG is better. It can join thick aluminum sheets and pieces with excellent strength. The constant wire feed fills the weld pool and covers gaps.
DIY & Home Projects
DIY and home projects do not require an extraordinary machine. For ease of use, the MIG welder is perfect. It is easier to handle and offers excellent weld quality.
You can also go with multi-process welding machines. They are suitable for working on different kinds of small projects.
Industrial Manufacturing
For mass production, the best welding method is MIG. Because it is fast and offers excellent weld quality and strength.
High-amperage MIG welding machines allow for working on large-scale projects. They can even weld extremely thick materials.
Companies also opt for automated systems. There are now MIG welding robots that weld on their own, saving the time of human work and offering better and consistent results.
How to Choose: A Step-by-Step Decision Guide
Here is a quick and concise guide to help you pick the right aluminum welding machine according to your needs.
Skill Level: If you are a beginner, there is nothing better than a MIG machine. It is beginner-friendly and quite easy to learn and master. For professional welders who need top-notch results, TIG is the right choice.
Primary Use: For welders who need speed over precision, MIG welding goes well. And if precision matters a lot, TIG offers high precision.
Material Thinness: For welding thin materials, TIG is the right choice. And if you want to weld thick materials, go with MIG.
Budget: If your budget is low, MIG is an affordable option. In case the budget is not an issue and you need to invest in a professional welder, buy a high-end TIG welder.
MIG and TIG are the traditional welding processes used for aluminum welding. For high-tech applications, exceptional precision, and incredible speed, Laser welding is the latest technology.
It is even faster than MIG and offers up to 8-10X speed. Its focused laser beam ensures high precision, which is not possible through any other welding process. It is ideal for intricate jobs. It also ensures minimal distortion of the metal due to minimal HAZ (heat-affected zone). And most importantly, it offers clean and strong welds with aesthetic appeal.
xTool Metalfab is a compact laser machine for metalworking. It can weld, cut, and clean a wide range of metals with a laser. It is compatible with aluminum and a wide range of other metals like steel, titanium, nickel alloys, magnesium, galvanized sheet, etc.
You can achieve incredible results because of its immense power, high speed, unmatched precision, and top-notch weld quality. It’s your all-in-one metal workshop with AI-powered optimization, user-friendly software, and the latest technology. You can use it for a wide variety of projects and applications.
Conclusion
Welding aluminum is difficult. But if you have the right welding machine and know the right technique, it will be as easy as with other metals. We have explained why welding aluminum is difficult and what type of welding processes are suitable. If you are looking for an aluminum welding machine, consider the important factors we have shared and select a suitable machine according to the use cases and applications.
