A Guide on How to Weld Aluminum: Comprehensive Guide

For this blog, we’ll give you the full rundown on how to weld aluminum – and everything that goes with it!

Not only will you be learning the process of welding aluminum, but we’ll also give you its pros and cons, who should do it, and many more!

Can You Weld Aluminum?

Yes, it’s possible to weld aluminum like any other type of steel. However, it’s treated to be a more unique and less common type of project.

The idea of welding aluminum is quite more challenging compared to other metals and steel, basically because of its general chemistry and composition – also because it is the most susceptible to breaking and cracking.

For us to gain a better understanding of that, let’s go ahead and take a look at welding and aluminum side-by-side.

NOTA: TIG or MIG welding aluminum are the two-bestand most popular welding options. However, other methods like electron beam, laser, and shielded metal arc welding (SMAW) can provide unique results.

Understanding Aluminum Welding

In a nutshell, it’s basically the welding of two aluminum products. Using the combination of heat and pressure, the goal is to join and fuse two aluminum products.

And while it’s a known fact that aluminum welding is difficult and challenging, it produces a strong, solid, high-quality weld that’s more durable and longer lasting than steel.

Is Aluminum Welding Difficult To Do?

Source: Weld Guru

Yes, welding aluminum is difficult. To properly weld aluminum, following the right procedures and steps, as well as using the right tools and resources like aluminum welding rods, shielding gas, brushes, etc.

To help you with it, let’s go ahead and discuss the difficulties in welding aluminum.

Spessore

The first hindrance or problem aluminum material imposes is its thickness. Aluminum often requires welding materials of varying thicknesses, from the thinnest pieces to the thickest and strongest ones.

Thin materials risk burn-through, where the effects can happen on the other side of what you’re welding. On the other hand, thicker sections may not achieve proper penetration.

Understanding the specific aluminum grade and selecting the right welding method are critical as well as adjusting settings like amperage and heat input; they help achieve uniform and consistent results even if thicknesses are different.

Conduttività termica

We know aluminum as one of the best conductors of electricity, in fact, taking the 4th spot after silver, copper, and gold.

Due to this, heat can dissipate and melt away fast, making it difficult for it to penetrate through the surface. To solve this, welders need to adjust their settings for higher heat input.

Additionally, preheating the aluminum can also help by reducing the temperature gap, allowing for the temperature to catch up faster and proceeding to weld joint formation.

Oxidation

When aluminum and air meet, a thin oxide layer develops. The said layer has an extremely higher melting point at 3761.6 °F (2072 °C) than aluminum itself, which is at 1220 °F (660 °C).

This layer acts as a barrier, which can make the welding process more challenging and difficult. Ultimately, it can lead to burn-throughs or weak joints.

Resolving this will require welders to remove the said layer before starting. Removing this layer can be done in different ways, but the most common and effective would be through chemical-induced processes, or by chemically using solvents or acids.

Others lean toward mechanical removal or through abrasives like sandblasting or using dedicated stainless steel brushes.

Impurities and Imperfections

Let’s not forget one of the biggest hindrances – not just of aluminum welding, but welding itself – impurities. These impurities like oil, dirt, air, and debris can compromise the weld zone, affecting both the strength and appearance of the joint.

They come from the environment (naturally), poorly maintained equipment, or improper material storage.

Discoloration, graining, or corrosion in a weld often signals impurity issues.

Hot Cracking

Hot cracking, or solidification cracking, occurs when aluminum welds are subjected to high thermal stress. This problem has historically made aluminum unsuitable for some arc welding applications.

Not to worry, though, because alloy treatments and advancements, as well as combining specific alloying elements have significantly improved aluminum’s mechanical properties.

Porousness

And last but most definitely not least, porousness. Aluminum is porous, meaning it can absorb gases and liquids through its surface quite easily.

This porosity weakens the weld’s structural integrity, leaving it vulnerable to stress and pressure.

Solutions are quite vast for porous substances, but the most famous would be by using shielding gas to keep the weld product from contaminating.

How to Weld Aluminum For Beginners: Top 4 Tips to Focus On

We’re not here to teach you the general process of welding aluminum, we’re here to guide and help you navigate in doing so!

NOTA: Check out Instructables’ guide to the basics of welding.

Chances are, if you’re reading this, you already know how to weld–just not aluminum!

On our end, we’re lucky because The Federal Group USA left us some tips to help us in our aluminum welding journey!

TIP #1: Focus on Hand Positioning

A steady hand is crucial when welding aluminum. Rest your hand on a solid surface, keeping the outside of your hand facing down. This technique helps maintain stability, resulting in a cleaner and more polished weld. Avoid angling the torch too much, as this can create a large, hard-to-control weld pool and lead to overheating in certain areas. Instead, hold the torch nearly straight, with just a slight backward tilt to keep your view unobstructed.

For TIG welding, ensure your hands work independently. One hand should guide the filler rod, while the other moves the torch smoothly. Keeping these motions coordinated will significantly improve weld consistency.

TIP #2: Mind the Temperature

Aluminum conducts heat faster than most metals, making temperature control critical. This high thermal conductivity can cause thin aluminum pieces to overheat quickly, leading to warping or burn-through. To counter this, allow the material to cool between weld passes. If you must revisit a section, be aware of how hot it has become to avoid accidental burns or heat damage.

Frequent pauses during welding can help distribute heat more evenly, preventing unnecessary damage to the workpiece. Remember, aluminum retains heat longer, so it’s essential to work methodically to minimize thermal stress.

TIP #3: Keep a Consistent Distance

Consistency in the distance between the tungsten electrode and the workpiece is key to achieving high-quality welds. Getting too close can overheat the metal and tarnish its surface, compromising the integrity of the weld. On the other hand, being too far away risks breaking the arc, which not only makes the weld uneven but also leads to excessive heat buildup on the workpiece.

The optimal distance can vary depending on the project, so adjust as needed. Practice maintaining a steady gap to keep the weld clean and uniform, and always aim to prevent arc breaks, as they can lead to visible flaws and overheating.

TIP #4: Manage Electrical Conductivity

Aluminum’s excellent electrical conductivity can make it challenging to manage during TIG welding. This property allows it to melt faster than many other metals, requiring precise control over the welding current. Modern welding machines often come with current control settings, enabling you to fine-tune the power output to avoid overheating the material.

If your welder lacks this feature, be extra vigilant about maintaining a steady distance and pace. Moving too close or too far can cause sudden changes in current strength, leading to an inconsistent arc or even damaging the weld. Practicing with current settings and maintaining control will help ensure smooth, even welds.

Can You Weld Aluminum to Steel?

Source: Welding Mastermind

Welding aluminum to steel is one of the most common questions thrown because of how well they can complement each other.

And yes, you can weld aluminum to steel, but in the same way like how you would generally weld aluminum.

There are special techniques and processes that need to be met to successfully be able to weld aluminum to steel and vice versa.

What About Cast Aluminum?

Source: The Fabricator

So, welding steel and aluminum is possible, what about cast aluminum? To answer the question, yes, cast aluminum can be welded.

While cast aluminum is just molten aluminum poured and shaped specifically, it’s not identical to its predecessor.

They have similarities in terms of welding – both of them can be challenging, but with the right technique and resources, you’ll be able to ace it.

Trust HDC For All Metal Fabrications

Aluminum is one of the most common metals used in fabrication, and there are tons of reasons for that. So now that you know how to weld aluminum – and if you think it’s too much for you – don’t hesitate to work with our team.

For more than a decade, we’ve been in the business of providing high-quality metal parts and components to our clients. Whether it’s for manufacturing and production, automotive and aerospace, or even medical applications, you can count on us.

It doesn’t matter how challenging your needs are, if we have the right processes and resources for it, you can bank on us! Our expertise doesn’t just end in aluminum, we work with stainless steels, titanium alloys, leghe di nichel, and more, too!

So, for all your aluminum welding needs, contact us! Send us a message, give us a call! We’ll be more than happy to help! Get a free estimate of the service or product you’re after!