best techniques for joining aluminium

Have you ever wondered why joining aluminium isn't as straightforward as other metals? Aluminium is light, resistant to corrosion, and very versatile. However, its unique properties can make standard joining methods less effective. Choosing the best method for your project relies on factors like strength, durability, and cost. This includes welding challenges and adhesive innovations.

As industry experts in precision-cut aluminium, we understand that one size does not fit all. Some applications need strong welds. Others work better with clean, seamless adhesives or modular fastening systems. No matter whether you are in construction, aerospace, transport, or DIY, using the best techniques is vital for strength and efficiency. This guide will help you understand the best methods for joining aluminium.

Discover their benefits and drawbacks, and see which method fits your needs.

Understanding the Challenges of Joining Aluminium

Before choosing a joining technique, it's worth knowing the key challenges of working with aluminium. Certain traits set it apart from materials like steel and brass and influence the method used for secure, long-lasting joins.

Aluminium Forms an Oxide Layer That Affects Bonding

Aluminium naturally reacts with oxygen to form a thin but highly stable oxide layer. This layer can prevent adequate adhesion in welding and bonding applications. Therefore, thorough preparation and cleaning are essential before joining. Oxide removal is often needed to secure strong joins. You can use abrasive cleaning, etching, or chemical treatments to achieve this.

High Thermal Conductivity Creates Welding Difficulties

Aluminium conducts heat significantly faster than steel, making temperature control a challenge. During welding, heat dissipates quickly. This increases the risk of distortion, burn-through, or inconsistent penetration. However, specialised techniques, such as pulse welding or controlled preheating, counteract this effect.

Galvanic Corrosion Can Weaken Joints

When aluminium is joined to dissimilar metals, such as steel or copper, it can experience galvanic corrosion. This occurs due to an electrochemical reaction between the different metals. Such side effects are widespread in moist or marine environments. However, it can be prevented with protective coatings, insulation layers, or compatible fasteners.

Five Best Techniques for Joining Aluminium

Choosing the best way to join aluminium depends on several factors. These include material thickness, the type of application, and how durable it needs to be. Welding provides high structural strength but demands technical expertise and heat control. It's, therefore, more suitable for industrial applications like automotive manufacturing and aerospace engineering. Alternatively, adhesive bonding is a low-heat solution that ensures seamless, corrosion-resistant joins. It's ideal for lightweight construction and modular assembly. For projects requiring disassembly, bolting and riveting provide secure fastening. The best part about this is that it does so without altering the aluminium's metallic integrity.

Learning these methods helps ensure your approach suits functional, structural, and environmental needs.

1. Welding

Strong but requires precision.

Welding is a popular method for joining aluminium. It is widely used in industries like automotive, construction, and aerospace. However, due to aluminium's heat sensitivity, not all welding techniques are suitable.

  • Gas Tungsten Arc Welding (GTAW) AKA Tungsten Inert Gas (TIG) Welding: Uses a tungsten electrode and inert gas shielding to create clean, high-precision welds. It is best suited for thin sheets but requires extensive skill and control.
  • Metal Inert Gas (MIG) Welding AKA Gas Metal Arc Welding (GMAW): Uses a continuous wire feed for faster welding, making it ideal for thicker sections. However, improper technique can lead to porosity and weak welds.

Welding is strong, but it's not always the best choice. According to HSE Welding Guidelines, it may not work well for thin materials, joining different metals, or projects that need to save money. For further reading, check out our blog on Differences Between Brazing and Welding.

2. Riveting

Durable and common in aerospace and automotive applications.

Riveting is a mechanical fastening method. It involves inserting metal rivets through pre-drilled holes to secure aluminium sheets together. This method is widely used in aerospace, shipbuilding, and structural projects where strong joins are needed.

  • No heat is involved, which makes it ideal for thin aluminium sheets that might warp under heat.
  • It's long-lasting and reliable, particularly for high-stress environments like aircraft fuselages.
  • It's lightweight yet strong and maintains its structural integrity without adding excess material.

Riveting isn't great for waterproof or airtight uses, but it's still one of the most dependable ways to join aluminium.

3. Adhesive Bonding

A modern alternative to welding.

Adhesive bonding is becoming an increasingly viable option for aluminium joining. It is particularly effective in the automotive, aerospace, and construction sectors. This method offers seamless, lightweight, and vibration-resistant joins without the need for heat.

  • Epoxy Resins: Provides high-strength bonds suitable for structural applications.
  • Polyurethane Adhesives: Offer flexibility and vibration resistance and are ideal for automotive panelling.
  • Acrylic Adhesives: They are fast-setting and high strength and are used in marine and outdoor applications.

Contrary to popular belief, modern adhesives can be as strong as welding when applied correctly. Leading manufacturers now use structural adhesives in high-performance applications. For further reading, check out our blog on How to Join Aluminium Without Welding.

4. Bolting & Screwing

Simple, versatile, and reversible.

Bolting and screwing are straightforward, cost-effective, and ideal for DIY or modular projects. Unlike welding, these methods allow for easy disassembly and reassembly.

  • It does not require specialist equipment, making it ideal for home and workshop applications.
  • It can be used with dissimilar metals, avoiding galvanic corrosion issues.
  • Best for temporary or adjustable structures, such as frame assemblies and repairs.

While weaker than welding or adhesives, high-grade fasteners can provide strong, long-lasting connections.

5. Friction Stir Welding (FSW)

A high-strength advanced method.

Friction stir welding is an advanced solid-state welding process. It's used in aerospace, marine, and high-performance transport sectors.

  • It is stronger than traditional welding and eliminates defects like porosity and cracking.
  • Produces minimal heat distortion, maintaining aluminium's structural integrity.
  • It is environmentally friendly, as it does not produce harmful emissions.

FSW offers benefits but requires specialised machinery, making it far more costly for smaller projects.

Get Aluminium Cut to Fit – No Extra Work, No Waste

Stronger joins start with perfectly cut aluminium – no trimming, no hassle.

A secure aluminium join is only as good as the material behind it. So, are you using welding, adhesives, riveting, or bolting? If so, a poorly sized aluminium section can compromise strength, create more waste, and delay your project. The correct aluminium sizes will help make smooth connections. This reduces the risk of structural failure and saves you time and money.

Clickmetal makes aluminium joining effortless by providing cut-to-size aluminium for flawless assembly. We offer top-quality aluminium sheets, plates, bars, and extrusions, all customised to your exact needs. There is no need for extra trimming or modifications – just reliable, high-quality aluminium ready to fit. Order your precision-cut aluminium now and get it delivered fast across the UK.

Have a specific requirement? Speak to our experts now at 01794 526090 or get in touch.