Written by Marloes

Welding aluminum

Out of all the materials that can be welded, aluminum is one of the most difficult kinds of metals to work. For example, you'll need to weld at varying levels of current, to avoid damaging the fragile aluminum. If you're prepared, have the right tools, and a healthy dose of intellect, though, even aluminum can be welded together in a neat and sturdy way. In this article, we'll illustrate the basic principles of aluminum welding


Examples of aluminum welding

Because of its light weight, aluminum is often used to make, for example, scaffolds and ladders. Aluminum is also a much appreciated material in the car and modeling industries, and for making frames, furniture, or works of art. The pulse function also comes in a double pulse version. In that case, not only the current will be provided in pulses, but the material to be added as well. This ensures very neat welded connections, think of the neat rows of 'crescent moons'. For that reason, this way of welding aluminum is often seen in decorative work. The double pulse function is only possible on MIG/MAG welding machines.

What do you need?

What you'll need to weld aluminum

In order to weld aluminum, a TIG or MIG/MAG welding machine with a pulse function is indispensable. The pulse function makes the current pulse between base current and peak current. You'll need the peak current to burn through the top layer, the oxide skin, since it has a higher melting point than the aluminum itself. Once you've gotten through it, peak current would make holes in the material beneath, so you'll need to be able to continue welding at a lower power. That means you'll need a welding machine that can switch up and down over a large capacity range. A welding station's product name will already tell you a lot: the abbreviation AC indicates the appliance is suitable for welding aluminum.


Tips for welding aluminum
  • A common problem when welding aluminum is the welding connection becoming porous and therefore unreliable. In order to prevent this, it's important to get the material clean and free of grease beforehand using a brush. If you don't, your molten bath will be polluted by escaping hydrogen, making the connection porous. For the same reason, make sure the humidity in your welding space is low.
  • The stability of the welding arc and the gas flow matters too. If either of these get disturbed, hydrogen may still end up in the molten bath and you'll no longer be assured of a sturdy and neat weld.
  • Finally, your welding wire. There's a reason these are packaged and delivered according to a prescribed method. Make sure, then, that your wire is clean, before turning on the welding machine and holding the welding arc against the aluminum.

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