How to weld aluminium: some easy DIY tips

If you follow this blog and us at helviLITE, you also know that our aim is to help you approach the world of welding without fear. That’s why we have decided to explain to you how to weld aluminium, a material that requires special treatment.

Before starting to weld aluminium, let’s get to know it better.

Aluminium is an alloy. There are about 8,000 types and some of them cannot be welded, so you need to pay attention. Where do you see what all these alloys are made of? In the famous ‘production standards’ that we might tell you about later.
What is important for you to understand now is which of these alloys you can weld. Here is our advice. If you are working with a tube, sheet metal or parts with an ‘L’ or ‘T’ profile, these materials can usually be welded. If, instead, you have a ‘casting’, a part that is cast in a mould, it may not be possible to weld it. That said, we’ll let you in on another precious piece of information.

What is important for you to know about DIY aluminium welding

Aluminium always has a shiny and attractive appearance. Its surface layer is composed of aluminium oxide (called alumina) of varying thickness: from a few microns to millimetres.
The valuable information is that aluminium alloys melt from 500° C to just under 700° C, but alumina melts over 2500° C! Does this mean that to weld you would have to bring everything up to 2500° C? Not at all, because there are welding processes that manage to ‘clean’ (the technical word is deoxidise) aluminium. Now, let’s make it clear: welding machines cannot work miracles (yes, we at helviLITE are getting ready, but for now we are ‘settling’ for easy-to-use welding machines). That’s why you need to give your welding machine a hand.

What you need to weld aluminium

To clean aluminium, you need:

  • brush with stainless steel wires;
  • grinding wheel with flap discs;
  • acetone or pure alcohol;
  • patience (but if you’re a DIY enthusiast, you’ve got some to spare, right?).

First, you remove the oxide with a brush or flap disc. Then degrease the workpieces to be welded with acetone or alcohol. We recommend for you NOT to use paint thinner because it leaves an oily residue. This way you will get a better weld.

Be careful, however: aluminium oxidises in just a quarter of an hour, so clean it immediately before welding: clean, spot-weld and weld immediately.

How to weld aluminium at home: the trick is heating the workpiece

Before welding, here’s one last tip. Aluminium is a very good conductor of heat, so if the workpiece to be welded is nice and big, you have to heat it up to 70° C (at least). To do this, use a propane flame and avoid makeshift methods, such as putting the workpiece in the oven. You could start a war with who does the cooking at home!

Good. Now that you have all the information, you’re ready to understand how to weld aluminium.

TIG and stick welding on aluminium: difficult but not impossible

We recommend that you choose these types of welding only if you are already familiar with welding. You need a great deal of manual skill for both.

To stick-weld this material, you need special electrodes. They are difficult to use and you have to be good at it: in short, it is for welding masters.

With TIG, things change very little. You need a welding machine specifically designed to weld aluminium, that is an AC TIG. The acronym AC stands for ‘alternating current’: it is the current that cleans and heats aluminium, allowing you to weld it. Our DIY TIG welding machines use ‘direct current’ and therefore you CANNOT use them to weld aluminium.

How to wire-weld aluminium: it’s simple even if you’re a beginner

If you have just learnt how to weld or are welding for do-it-yourself projects, we recommend you use a wire welding machine.

First of all, you need to get the right accessories for wire welding: torch liner, contact tips and special rolls for aluminium. Argon is the gas to weld aluminium. It is a completely inert gas, that is it does not react with the metal. That’s why the process is called MIG: Metal Inert Gas. It’s an old acronym but you can use it to show your friends that you know your stuff. The wire for welding aluminium, instead, varies depending on the type of alloy you need to weld. To buy the right one, get advice from your dealer.

All wire welding machines can weld aluminium. You just need to get the right equipment and set it up correctly. But watch out: aluminium is, and always will be, a complicated material to weld, and so we recommend that you go to a professional with a pulse wire welding or an AC TIG welding machine to get better results.

However, if you want to give it a try and you are ‘satisfied’ with the aesthetic result of the welded workpiece, you can use our multiMAKER 192, which has a dedicated aluminium programme and is designed specifically for hobbyists and those who want to weld at home. Basically, setting it up is quick and easy: you only have to worry about getting to grips with it and making WOW projects.