How To Fix a Cracked Aluminum Weld – An Expert Advice

Aluminum is a great material to work with when you need a metal that is lightweight, easy to cast and form, resistant to corrosion, and non-toxic. We use aluminum alloy in a lot of things, from kitchen utensils to automobiles, even in our electronics. It’s incredibly useful, and it is extremely rare for you to find a welder that doesn’t know how to work with them. However, it’s certainly not without its flaws either. Even as an alloy, aluminum is one of the most malleable metals in the world. It is prone to bending or warping under certain conditions like improper distribution of weight, intense heat, or any powerful outside force. For aluminum fabrications in Leeton, this is quite troublesome because it could cause the welds in the joints to crack and, in the worst cases, break altogether. When this happens, what exactly can you do?

We have good news for you. Repairing damages on aluminum welds is much easier than most people think, given that you have the materials to do it. Although it certainly helps to have an experienced aluminum fabricator do it, any person with basic welding training can pull it off without any issues. In this article, we’ll explore the most common methods of repairing a cracked aluminum weld.

What you’ll need:

First of all, make sure you have all the proper safety equipment before you start welding. This includes gloves, protective goggles, and a welding helmet. A welding apron can also come in handy if you don’t want splatter ruining your getup.

Although it is possible to make repairs using a multitude of welding methods in Hillston, we’ll keep this guide simple and focus on TIG welding. It is arguably the best option for making repairs because you have better control over the application of the filler metal. It’s also great for making small, precise welds that you’ll often encounter when repairing small cracks. Prepare all the materials you normally would have when you’re doing TIG welding. We recommend using a serrated tungsten electrode and a 4043 aluminum filler rod. Set the TIG welder to AC at around 200–300 amps output, going for higher amperage as the thickness of the weld increases.

You will also need a drill and a grinder for when you have to smoothen out the crack before you weld. As for the steel brush, we recommend using one that is used specifically for aluminum, to avoid contaminating the joint as you clean it. Last but not least, you should have a clean welding rag and acetone.

Step 1: Prepare the weld

Identify the correct length of the crack by marking the areas where it starts and where it ends. You should also take note of its depth, especially if it extends to the base metal. Drill a hole at both ends of the crack, then grind out the crack so it becomes a V-shaped indentation or groove. Make sure you grind as deep as the root of the crack to prevent it from reappearing. Next, cleanse the area with a clean rag soaked in acetone, then scrub it with a steel brush, making sure to reach deep into the crack so the acetone can clean it as well.

Step 2: Welding the Crack

Begin welding where the crack starts, ideally in one of the holes you drilled earlier. Heat the base metal first before you add the filler metal. Start filling in the groove with the filler metal, following the usual steps in welding you’d normally do with TIG welding. Be careful when you apply the filler metal, because applying it when the base metal has not yet been properly penetrated might cause the filler metal to accumulate at the top instead of merging with the base metal. Slowly make your way to the other end of the crack. Leave no gaps in the groove, as these may turn into new cracks in the future.

Step 3: Finishing Up

Get your wire brush once more and clean the weld area. When done correctly, you should see an even row of beads where the crack had once been. 


That should be enough to ease your worries the next time you see cracks in your aluminum fabrications. Note that when you’re working with other materials, like stainless steel fabrication, the process might be slightly different, but the core concepts remain. If you’re not too confident with your TIG welding skills yet, practice on a small plate of aluminum first. Work on applying the filler metal evenly to get the right amount consistently. There are several references online you can look at to tell if your weld was done correctly, but don’t sweat it if you don’t get it the first time. 

Looking for professional metal repair, modification, and welding services in New South Wales, Australia? Give Topweld General Engineering a call today, and we’ll set you up with our finest welders right away.

Learn more about aluminum fabrication using this guide: ALUMINUM FABRICATION: BASIC GUIDE 2023


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