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Guide To Aluminium Welding: What Is The Best Welding Method?

Arya Ebrahimi
17 Min Read
MIG welding defects can cause downtime and lost productivity due to rework. Use these tips to help you minimize these costs by quickly identifying and resolving MIG welding problems.

As one of the most common types of metal, it may shock you to know that it’s not particularly easy to weld. Aluminium is a softer metal that has a smaller window in which it can be welded, making it more difficult to work with. Because of this, aluminium is more prone to being blown out by the average welder and produces weaker welds. So is there any way to weld this metal?

Tungsten Inert Gas welding, or Gas Tungsten Arc Welding, are the safest and most efficient ways to weld aluminium. It is possible to weld with a MIG welder, but only if the sheet of aluminium is unusually thick, as the MIG welder is designed for thicker metal sheets.

A number of people are not even aware that it is possible to weld aluminium. Hence, we have put together a short guide to brief you about welding aluminium — from the metal’s properties, safety precautions, and welding processes, among others. 

If you’re looking for the most cost-effective way to weld aluminium, consider speaking to an expert aluminium welder about your options. An experienced metal fabrication company can advise you on the best way to achieve the results you need.

Continue reading to learn more about MIG vs TIG welding for aluminium!

Can You Weld Aluminium?

Yes. Aluminium can be welded by using a TIG welder, a GTAW welder, or a specifically low powered MIG welder. It takes specialised welding professionals with the right equipment to safely weld this metal without damaging it.

Aluminium is inherently difficult to weld due to its nature — soft, highly sensitive, and insulated by a tough oxidised layer. This difficulty is exacerbated by the fact that aluminium is very susceptible to impurities when in its molten state, which may result in weak or porous welds.

Aluminium and its related alloys have an affinity for Oxygen. Pure Aluminium melts at 1,200°F (650°C), while the oxide that protects it melts at 3,700°F (2,037°C). Since the oxide’s melting point is much higher than the aluminium itself, the oxidised layer has to be removed prior to welding.

Aluminium’s higher thermal conductivity and low melting point gives it a slim window of workability compared to other metals which are easy to weld, like various types of steel.

Is Welding Aluminium Difficult?

Welding aluminium is difficult because it has a low melting point and is highly thermally conductive. This means that it takes a smaller amount of heat and a shorter time to melt and potentially damage the metal. This is why only professionals should attempt to weld aluminium.

This is also the reason aluminium is difficult to laser engrave correctly. While it can be etched, as well as laser cut and welded, aluminium fabrication requires specialist experience to carry out correctly. 

Although aluminium is an incredibly versatile metal found everywhere in our lives, it’s not as easy to work with as you would think, especially when it comes to welding. It’s incredibly easy for aluminium to be overheated with the average welder, and shouldn’t be attempted at home for not only your own personal safety, but for the safety of the piece you are working on.

Is Aluminium Safe To Weld?

Aluminium is safe to weld for trained professionals provided that individuals in the vicinity of the welding process are wearing Personal Protective Equipment (PPE) and are using fume extraction torches alongside fume extraction systems to reduce the amount of particles that can be inhaled by up to 95%.

Arc welding aluminium produces gas and particles, which in this context, are collectively referred to as welding fumes. When welding this metal, it produces Aluminium Oxide in the form of particles, which range in size — from 10 to 400 nanometers. The size of these particles will determine how far into the system they can go when inhaled, and whether they can penetrate the alveoli in the lungs and accumulate.

Excessive inhalation of Aluminium Oxide may lead to respiratory and lung diseases, usually in the form of Bronchitis. The welding process also produces what is called the gas ozone, which is created when the arc from the welder produces UV radiation. Although MIG and TIG welding produces less fumes, it produces more gas ozone than MAG welding.

What Type of Welder Can Weld Aluminium?

A TIG and GTAW welder can reliably weld aluminium; a MIG welder can also weld aluminium, but it’s far less reliable. Any other type of welder risks damaging the surface of the aluminium you are welding, and the splattering could come in contact with the person welding.

TIG Welding, also known as Gas Tungsten Arc Welding (GTAW) involves a Tungsten electrode that runs a current through the metals you want to join. On the other hand, MIG Welding involves feeding a metal wire connected to an electrode that melds the materials together.

During the welding process, both TIG and MIG torches produce an electric arc between the material and the electrode. The metal is melted this way and allows the filler material to combine with it. Nowadays, it is much more common to see TIG welding for aluminium than MIG welding.

Plasma welding with direct current is another type of welder that can weld aluminium and is considered advantageous with regard to the fact that heat can be directly introduced into the workpiece, but it’s a very challenging process.

MIG Welding for Aluminium

MIG welding is one of the two most common types of welding currently found today, but it’s not ideal for aluminium. MIG welders operate at high temperatures and work very quickly, which makes it a great fabrication tool, but not if you’re working with aluminium.

That being said, a MIG welder modified to work slowly at low temperatures, specialised for aluminium, can be used in a pinch where TIG welders aren’t available. 

Pros of MIG Welding for Aluminium 

Benefits of MIG welding include: 

  1. Less Time to Weld – welds are created in a shorter amount of time.
  2. Lower Cost – Not as expensive as TIG welding, and equipment is much more accessible.
  3. Accuracy – Much easier to get an accurate bond compared to TIG welding.
  4. Clean Process – The process is clean and is therefore good for the environment.

Cons of MIG Welding for Aluminium

Although MIG welding is incredibly common, it’s not a universal answer for welding applications. Some of the negatives of MIG welding include: 

  1. Cools Quickly – MIG welder welds cool much faster than those of other welders. This can be an issue if you are wanting to make correct mistakes.
  2. Weld Orientation – Because of the way a MIG welder works, it’s essentially impossible to weld something upside down or vertical. This makes welding larger structures that cannot easily be rotated difficult. 
  3. Immobile – MIG welders are largely immobile and use a shielding gas that can easily be interfered with by the wind. For this reason, they are only found in metal fabrication workshops.

TIG Welding for Aluminium

Of all the different welding methods used today, TIG welding is often the most used for welding aluminium. Because TIG welders usually operate at a slower speed at lower temperatures, it gives a trained welding specialist time to work with the very thin metal and reduce damage to the surfaces being welded.

Pros of TIG Welding for Aluminium

Benefits of using TIG welding for aluminium include:

  1. Precision – Welds from TIG are much more precise, and generally have a higher quality than MIG welds.
  2. Clean Process – The process is clean and is therefore good for the environment.
  3. No Filler Required – TIG welding does not need filler material.
  4. Greater Control – Allows for foot control to adjust heat input accordingly.
  5. Lower Maintenance – Does not consume the welding electrode unlike TIG welds. In addition, the electrodes do not need much upkeep aside from routine cleaning after every use.

Cons of TIG Welding for Aluminium

TIG welding isn’t perfect for every scenario. Downsides of TIG welding include:

  1. Cleanliness – Although TIG welding is a very clean process, it needs to be clean to work properly. Dirty or smudged materials can significantly affect the quality of the weld. 
  2. Costly – On average, TIG welders and components are more expensive than other types of welders. 
  3. Speed – Although you have greater control with a TIG welder.
  4. Difficulty – TIG welding is harder to perform than other types of welds and requires much more practice to do proficiently.

What Is The Cheapest Way to Weld Aluminium?

MIG welding is the cheaper option to weld aluminium, though the quality and strength of the joint are not as good. TIG welding is slower and therefore costs more, but the results are superior for joining aluminium. 

Stick welding is typically the cheapest way to weld metal, but not recommended for aluminium, since it uses a flux. This can result in the porosity of the final product and compromise metal strength considerably.

Stick welding, also known as Shielded Metal Arc Welding (SMAW) is one of the most cost-efficient types of welding, going back to the late 1880s. Although it is common for beginners and enthusiasts alike due to its affordability, using the process for welding aluminium is known to be extremely messy, which leads to molten splatter.

When getting a quote on aluminium welding from a metal fabrication service, your provider can explain each welding option, as well as how much it will cost. The advice of a professional is critical here, as they can let you know what type of welding will be suitable for your application – the cheapest option may be unsuitable for the results you need.

What Is the Easiest Way to Weld Aluminium?

Because aluminium has a lower melting temperature, MIG welding is the easiest way to weld aluminium. While other types of welders can be used, they risk blowing out or damaging the aluminium during the welding process. 

Every aluminium welding process has its own set of challenges, there is no easy way for it. However, these challenges and difficulties can be managed by knowing the proper way to undertake the welding processes. 

Unlike TIG Welding, MIG Welding does not require any filler materials during welding, which turns it into a one-hand operation. In addition, the process allows for the adjustment of heat intensity through foot control. MIG Welding also allows for a smoother and simpler movement of the welder across the material, unlike TIG welding, which requires a slight and consistent forward and backward movement as the welder moves across the metal. 

One of the primary factors which make TIG welding a lot more difficult is the fact that during the welding process, the filler rod and electrode on each of your hands must never touch as they move along the material.

The pre-welding preparations are also much more straightforward in MIG Welding. Equipment used for the process always requires Direct Current (DC), unlike TIG Welding which can either be Direct or Alternate Current depending on the machines used.

Do I Need To Prepare Aluminium Before I Weld It?

Yes, any piece of metal must be clean before it is welded. Dirt, grease and oils will all affect the quality of the weld and a reputable fabrication company will ensure they clean any piece of aluminium thoroughly before attempting to work on it. 

Before starting any welding process, solves like acetone or mild alkaline solutions are used to remove the oil, dust, dirt and grease on the surface of the metal. It’s also important to remove any traces of water vapour on the metal. 

A stainless steel brush is also used to strip away surface oxides, but some prefer to use strong alkaline or acid to achieve the same results. The cleaning process needs to be done as close to the time of welding as possible. It’s essential to work with welders and fabricators who use an extensive cleaning process to ensure any work they do for you is of the highest quality and strength. 

What’s The Difference Between Welding, Soldering and Brazing?

Soldering uses a tool called a soldering iron that uses copper tips to directly heat a seam between metal, and brazing is a similar process that functions at much hotter temperatures over 450°C. In comparison, welding works at higher temperature, and heats a filler material to act as a ‘glue’ between metal surfaces. 

Can You Join Aluminium Without Welding?

You can join aluminium without welding, although the results won’t be as good as if you were to weld aluminium together. You can use screws or rivets to join pieces of aluminium if you don’t have access to a welder. However, welding is the most advised way of joining aluminium. 

Using a torch to heat and join pieces of aluminium or brazing are other methods of joining aluminium, but function similarly to welding.

Overall, welding is the optimal solution for joining pieces of aluminium together. It can be difficult to get the right angles needed to screw aluminium together in a way that will be sturdy, and riveting aluminium also faces similar structural issues. Welding aluminium is the best way to join aluminium pieces.

Who Can Do Aluminium Welding?

While it’s possible to weld aluminium at home as an amatuer or hobby welder, it’s best to leave it to the professionals. Aluminium is a particularly tricky metal to try and weld because it is so soft and has a relatively low melting temperature, and requires years of training to be able to weld properly.

Trying to weld aluminium at home is never advised, especially since this metal is known for splattering when it’s welded. The metal is also particularly prone to being blown out or damaged by welders that are too forceful, which can permanently damage your work area.

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