Tips You Need to Know for Welding Aluminum
Welding can be a challenging task even for the most experienced welders. Not only does welding aluminum require different techniques and tricks than welding steels, it's a skill needed to complete a variety of different projects.
Despite it's difficulty, there are tips and tricks you can keep in mind to develop your skills with aluminum welding. With the right knowledge and enough practice, anyone can weld aluminum.
Keep reading to learn about how you can weld aluminum- from tips and tricks for success to the different techniques you can try out for yourself.
What Makes Aluminum Welding Difficult
Aluminum is an extremely common metal in the fabrication industry. It doesn't corrode over time, it shines in the lights, and it's lightweight.
Despite these things making aluminum desirable, these same things make it very difficult to weld. Aluminum is very soft and sensitive to outside factors. When it's molten, it can be susceptible to various forms of impurities.
For you, that means a porous and weak weld that won't stand up to the test of time.
In addition, aluminum has a layer of aluminum oxide on the outside of it, which melts at a much higher temperature than the rest of the aluminum inside of it. It requires high heat to burn through it, but control over that heat. If you burn too hot too quickly, it'll burn holes into the pure aluminum layer underneath.
Aluminum can be contaminated by the air itself due to poor shielding or excessively long arcs. Oxygen can reduce how strong the aluminum is and its ductility.
Finally, if you're working in a humid area, hydrogen can be introduced to the environment and create air bubbles throughout the cooled aluminum. This can happen if the weld joints are damp as well.
All of these issues aside, there are ways you, as an experienced welder, can avoid these common pitfalls.
Benefits of Using Aluminum
Despite the difficulties that come with using aluminum, it is extremely beneficial in many applications. It's lightweight and has a great strength-to-weight ratio in comparison to many other metals. That means it gets stronger instead of brittle when the temperature goes down. On projects that need to be strong yet light, aluminum is a great choice.
Aluminum also is recyclable and absorbs paint and sealant, so it's often chosen for its global footprint and its aesthetic appearance.
Finally, aluminum is able to conduct electricity and heat almost as well as other more commonly-used metals like copper and is completely non-corrosive.
Wear The Right Protection
When you weld any kind of material, you're exposing yourself to high heat and plenty of danger. You need to always wear the correct personal protective equipment (PPE) when working and educate yourself in every safety procedure possible.
This means understanding the nearest fire escapes, understanding where to go in case of equipment malfunction, and understanding your efforts in preserving your safety means a long and successful career in the industry.
Avoiding Impurities and Hydrogen Bubbles
This may be one of the easier things to solve when working with aluminum. Impurities are introduced to aluminum through messy work environments and unclean aluminum.
Use a solvent like acetone to remove oil, grease, and water vapor from the aluminum's surface before working with it to ensure it's clean.
Ensure your aluminum is fully dry before working with it, and ensure that it's free of any and all moisture particles. Once you've done that, you've reduced the likelihood of weakening your weld and have decreased your chances of seeing hydrogen bubbles in your final weld.
Breaking The Alloy Layer
Ensuring an even melt might be the trickiest thing to do. You have to be in complete control of the temperature at all times to ensure you get the perfect finished product. Hot enough to go through the alloy later but cool enough not to burn the pure aluminum beneath.
This will take practice, but there's a few things you can do to help. Before working with your aluminum, use a stainless steel wire brush that you only ever use on aluminum to remove oxides from the surface. Then, wash and dry the part thoroughly.
Doing this will provide you with an easier time in handling the aluminum and help it heat more evenly, giving you a neater final product.
What Methods Work?
Theoretically, you can use stick welding methods, GTAW/TIG methods, and GMAW/MIG methods when working with aluminum. It is, however, not very common to use stick welding techniques.
This is because stick welding can be extremely messy when working with aluminum.
However, it could be advantageous to use this method when working with rusted or painted metal pieces because it can allow you to work without a shielding gas.
Gas Tungsten Arc Welding (GTAW)
This method is also known as tungsten inert gas (TIG) welding, and it's the most common method chosen by professionals when working with aluminum. It's common in the automotive industry and is often seen as a welding technique for professional racing teams.
This method requires a consistent current with alternating current capabilities. It uses 100% argon as a shielding gas. It doesn't use any mechanical wire feeding; instead, you, as the welder, feed filler material into a puddle.
It's much cleaner than the stick welding method because the alternating current cleans the oxidized layer off the aluminum as it welds it together.
It also aids in preventing contamination, which, as we've gone over, is an extremely common problem when working with aluminum.
Gas Metal Arc Welding (GMAW)
GMAW, commonly called metal inert gas (MIG) welding, is another method commonly used when welding aluminum.
This technique can often be completed much quicker than other methods and has higher deposition rates than TIG welding.
However, it does have a mechanical wire feeding system, which means you have to use a push-pull gun or a spool gun to make wire feeding possible. This means more tools and items for you to keep track of when welding.
To combat the aluminum from experiencing problems with porousness, you must make sure the base material and filler rod are clean, moisture-free, and have excellent shielding gas coverage.
What If I Want Something Different?
There are a variety of different techniques you can use instead of TIG, MIG, and Stick Welding techniques when working with aluminum.
You could try laser beam and electron beam techniques, which use precise heat zones that are easily controlled by the welder to make a clean and fast weld. It's great for materials that crack easy like aluminum, but it requires specialized machinery you may not have access to.
You could try resistance welding, but you must keep in mind the high thermal and electoral conductivity of aluminum while you work. While it can work, it's not an advised or common method.
You could try shielded metal arc welding (SMAW) methods, but it's not recommended by our team. You might be able to repair cast aluminum with this method, but it oftentimes produces lackluster results.
What To Avoid
Understand that when you're working with aluminum, you must always be flexible. There is never one perfect solution when working on a project that requires aluminum welding. You need to use your knowledge and skills to find the best solution for that project and trust in your own ability to do it right.
You shouldn't base your technique and experience on your previous work with other materials, either. Working with aluminum is very different than working with any other metal, and it requires its own unique skillset.
You must always be prepared for the worst with aluminum as well. Ensure you have the proper tools and solvents to clean and store aluminum without worrying about water vapor, and ensure you are beginning your weld by minimizing as many negative factors as possible.
Finally, details are everything. The smallest mistake can mean you ruin an entire aluminum welding project. Double-check your work to ensure you haven't forgotten any preventative measures to ensure the best weld possible.If you want to learn more about metalworking and manufacturing, sign up for our newsletter to learn all about the ever-changing world of manufacturing.