Welding is an awesome skill to have. But even the most skilled welder will have many challenges when trying to weld aluminum. Posing the question: can you weld aluminum?
Steel is a common material to weld and it is extremely malleable. Aluminum is a whole different kettle of fish. It involves different techniques and processes and without them, the entire process would fail.
In this article, we discuss if aluminum can even be welded. We also discuss what knowledge you need to get the job done correctly and the different types of welding there are to help.
Let’s get into it!
What Is Aluminum?
Aluminum is more than the aluminum foil you use to come leftovers in the fridge. This material is light, durable, and functional making it extremely valuable in our society.
The thirteenth element in the periodic table, aluminum, is a silvery-white metal. A shocking fact about aluminum is that it makes up more than 8% of the mass of the Earth’s core and is the most common metal on the planet.
Aluminum is not a natural material that cannot be produced from the Earth in a pure form. It binds with other elements. It is most commonly found as aluminum sulfates. These are combined and used to clean water, cooking, and even in medicine.
Why Is It Difficult To Weld Aluminum?
A frequent kind of metal used in manufacturing is aluminum. It’s non-corrosive, portable, and attractive, making it the perfect material for a range of welding. The qualities that make aluminum desirable can, however, make it challenging to deal with.
Aluminum is a soft material that is covered by a tough oxidized layer. When it is in it’s molten state, the material is at its most vulnerable state and is highly susceptible to impurities. This can lead to issues when welding later on.
Oxygen and aluminum have a strong affinity for one another. The oxide that covers aluminum melts at 3,700°F (2,037°C), while pure aluminum melts at 1,200°F (650°C).
Before welding can start, the oxide must be removed from the metal since it melts at a temperature that is almost 2,500°F (1,370°C) higher than the aluminum itself.
The features of having a higher thermal conductivity and low melting point mean that there is a smaller window to work with aluminum and it quickly burns through. Other factors to consider are:
Porousness: Aluminum absorbs hydrogen more quickly as it warms up when it is molten. As the metal solidifies again, the hydrogen separates, which might create bubbles in the substance and make the metal porous and weak.
Thickness: When welding aluminum, various material thicknesses must be taken into consideration. Welders need to be able to penetrate thick materials sufficiently to produce a strong weld without burning through thinner materials.
Oxidation: Aluminum has an oxide layer on top and this layer melts at a much higher temperature than aluminum. You need high heat in order to melt this layer without burning any hole into the aluminum underneath. Possible but extremely difficult.
Impurities: Due to its high sensitivity, aluminum can be contaminated by water, air, and soil in a variety of ways during the welding process. Due to inadequate shielding or too lengthy arcs, aluminum can become polluted by air that enters the weld.
Oxygen can decrease aluminum strength and cause oxide to form on the aluminum welds which will alter the appearance of the material and make welding more difficult. Aluminum must be stored and cleaned properly before you begin welding.
How To Weld Aluminum
Now, that we know what to watch out for when welding aluminum, we can finally get into the correct process!
The metal must be carefully cleaned by the welder before even starting the welding process. As was already noted, one of the problems with aluminum is that contaminants tend to stick to it more easily. So it’s important to prepare the content properly.
1. To clean the material use an acetone or milk alkaline solution. Remove any oil, grease, or water from the surface and make sure it is dry.
2. The metal must be carefully cleaned by the welder before even starting the welding process. As was already noted, one of the problems with aluminum is that contaminants tend to stick to it more easily. So it’s important to prepare the content properly.
3. Set up the joint and cover it if you are not welding straight away. This will keep the area clean from dirt or grit.
Always ensure the aluminum is stored at room temperature and is welded within a couple of days. It is crucial that your safety comes first. This means wearing the correct safety gear such as goggles, gloves, welding helmets, and leather.
You may also wear fume ventilation to protect your lungs from welding fumes.
Types Of Welding
There are different types of welding that can work for aluminum such as:
GTAW/TIG
One of the most often used welding methods for aluminum is gas tungsten arc welding (GTAW), sometimes referred to as tungsten inert gas (TIG) welding. Welders for professional racing teams and auto enthusiasts both frequently employ this welding technique.
GMAW/MIG
Compared to TIG welding, this form of welding frequently has faster travel speeds and higher deposition rates, which affects the weld quality. But because it uses a mechanical wire feeding system, the welder might need to use a spool gun or a push-pull gun to enable wire feeding.
Final Thoughts
Welding aluminum is possible with the correct process and skills. Aluminum is an extremely sensitive material that has to be treated with care in order to mold and form.
If you are impatient or aggressive, you will burn through the oxide layer and cause damage.
Whether you use GMAW or GTAW methods, be sure to keep your aluminum clean and dry before and during the welding process. If there is any dirt in the joint, you will run into some serious problems.
Now, get your safety gear on and get to welding aluminum!
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