How to Weld Aluminium: A Comprehensive Guide to Speciality Metals’ Aluminium Products

Challenges of Welding Aluminium

Aluminium is a unique material with properties that make it both attractive and challenging to weld. Here are three critical challenges fabricators face:

• High Thermal Conductivity: Aluminium dissipates heat quickly, meaning it absorbs and spreads heat away from the weld zone faster than steel. While this reduces the risk of overheating, it also makes achieving consistent weld penetration more difficult.
• Low Melting Point: Compared to steel, aluminium melts at a lower temperature, increasing the risk of burn-through, especially on thin sheets or woven mesh.
• Oxidation: Aluminium forms an oxide layer on its surface, which melts at a much higher temperature than the base metal itself. If this layer isn’t removed before welding, it can result in contamination, weakening the weld and leading to imperfections.

Understanding and addressing these challenges is crucial to achieving high-quality welds on aluminium.

Welding Processes for Aluminium

Each welding process has its strengths and is suited to specific aluminium products. Below are the most common methods:

TIG Welding (Tungsten Inert Gas):

• TIG welding is renowned for precision and is ideal for thinner materials like sheet metal or woven mesh, where heat control is critical.
• The process provides clean, aesthetically pleasing welds with minimal spatter, making it perfect for applications where appearance matters, such as decorative pieces or visible joints.
• TIG welding requires more skill and patience but delivers professional-grade results.

MIG Welding (Metal Inert Gas):

• MIG welding is the go-to method for thicker aluminium pieces, such as round tubes and flat bars. It’s faster than TIG welding and more suited to structural or industrial applications where speed and strength are priorities.
• A spool gun or push-pull system is often used for feeding aluminium wire to prevent tangling.
• The process is relatively easy to learn, making it ideal for DIY projects as well as professional fabrication.

Stick Welding:

• Stick welding is rarely used for aluminium due to its limitations in achieving smooth, precise welds. However, it may be an option for repairs or low-budget projects.
• It’s primarily used for thicker aluminium sections but is not recommended for professional-grade finishes or intricate work.

Preparing Aluminium for Welding

Preparation is key to successful aluminium welding. Here’s how to get started:

Cleaning the Surface:

• Aluminium’s oxide layer must be removed before welding. Use a stainless steel brush (dedicated to aluminium use only) or chemical cleaners designed for metal preparation.
• For thicker sections like flat bars or U channels, ensure both edges to be joined are thoroughly cleaned to improve weld penetration.

Degreasing:

• Remove any oils, dirt, or contaminants using acetone or a similar solvent. This step is especially important for woven mesh and sheet metal, where contaminants can disrupt the welding process.

Material Quality:

• At Speciality Metals, we pride ourselves on offering high-grade aluminium products that are ready for welding. Our materials, whether round tube or T section, are designed to provide consistent performance, reducing prep time and ensuring a smoother welding process.

By addressing these challenges and following proper preparation steps, you’ll set the stage for clean, reliable welds every time.