Aluminum is a strong, lightweight metal with an oxidized surface that prevents corrosion and wear. However, the same qualities that make this metal ideal for auto parts, furniture, and art pieces also make it difficult to weld. If you’re TIG welding this material, here are a few tips for creating a strong joint without impurities or weak spots.

How to Weld Aluminum

1. Choose the Right Gas Blend

Argon is typically used to protect the weld pool from atmospheric gases, and provides enough current to melt thinner aluminum pieces. However, thicker parts may require a hotter arc than your equipment can deliver. 

If you’re working with larger aluminum pieces, switch to a mixture of helium and argon. The blend increases the heat of the torch, helping you achieve maximum penetration.

2. Remove the Oxide Layer

The layer of oxidation that protects aluminum from the elements melts at a higher temperature than the metal underneath. To ensure the part you’re working with melts consistently, remove this thin coating before welding.

Denatured alcohol or industrial degreasers can usually remove the layer. Use brass brushes if you’d rather treat the metal mechanically, as their bristles are soft enough to prevent scarring. 

3. Use the Right Currents

Using the alternating current (AC) technique rapidly switches the metal's polarity, sending the electrical current back and forth through the material. This creates a sandblasting effect that removes oxidation as you work. Using AC is usually best for TIG welding, but it's also possible to use direct current (DC), which sends electricity from the electrode directly into the work surface. 

As you work, AC power will cause the electrode to get hotter. This may not be an issue for shorter projects, but the equipment may overheat if you’re working on a long bead or an especially deep weld. Switching to DC welding can correct any imperfections, such as gouges and porosity.

Whether you’re a professional metalworker or hobbyist, Wayne Oxygen & Welding Supply Co. has all the tools you need to make your TIG and MIG welds successful. They have locations in Waynesboro, Charlottesville, and Harrisonburg, VA. Their inventory includes supplies from some of the industry’s top manufacturers, including Lincoln Electric Company® and Miller Electric Manufacturing®. Visit their website for a closer look at their welding equipment. To ask about their stock, call (540) 942-4145 to reach their shop in Waynesboro, or (434) 295-2334 to speak with someone in Charlottesville.