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Experienced MIG welders often spend a lot of hours mastering steel. They fire up the MIG torch and set their arcs on steel surfaces of varying types, chasing the beautiful and strong weld finish. As a result, they know how MIG welding machines behave, and they know how to tame them before they come into contact with the workpiece.
Metal Inert Gas (MIG) welding for aluminum is a different challenge, however. So for amateur and seasoned welders who are new to this idea of aluminum welding, it's best to start with knowing where you can use it in your personal or professional welding gigs.
Aluminum is an outstanding material to work with within many fabrication projects that normally use steel. Professionals and hobbyists who haven't used it before but are open to challenging themselves can start playing with aluminum for their projects first. As a welder new to dealing with this shiny metal, you can start working on small-scale house projects. Welding simple modular components such as window frames or small side tables for areas in your home are both good starting points. Then you can move on to more complex fabrication projects such as aluminum ceiling fixtures, stairs, and patios.
Another use for aluminum is for large-scale industrial or commercial projects like automotive manufacturing, aeronautics, and construction. These industries require processing large volumes of aluminum sheets that vary in thickness. These aluminum sheets are cut, bent, and welded and are installed or attached as a component of a larger product.
Cars in the automotive industry are now processing aluminum for their cars' bodies because it makes the car lighter and more fuel-efficient, compliant with the CAFÉ (Corporate Average Fuel Economy) rules. This opens opportunities for welders looking to get their hands on welding aluminum professionally or even personally.
Aluminum is a difficult material to work with compared to carbon or stainless steel. But this challenge can also be fun to conquer once you learn the benefits it brings to your worktable.
The primary factor that makes aluminum challenging is the oxide layer. The surface of aluminum is covered with a tough oxide that makes it hard to fuse or weld together.
High thermal conductivity is another hurdle for welders trying out aluminum. This metal heats up fast, making it hard to gauge just how slow a pass should be. Too slow, and you can punch a hole through to the opposite side of the aluminum.
As you MIG weld aluminum, it also increases temperature and brings water molecules into the liquid pool. The problem occurs when it starts to cool down. It spits the hydrogen back out to the surface, making the welded surface porous.
The process of heating up aluminum by welding it also makes it susceptible to elements in the surrounding air. This is a recipe for weak and low-quality welds due to impurities.
Oxidation not only poses a challenge to welders, but it also brings them benefits. The oxidized layer of aluminum makes it resistant to corrosion. Successfully integrating aluminum into your projects will make it rust-free and maintain its quality for a long time.
Aluminum can also be bent, welded, or molded without losing its intrinsic toughness. Couple this with its lightness, and you get a durable and lightweight material that looks pretty and doesn't rust out.
We know that the difficulties and the benefits of aluminum have got you excited to tackle this new challenge. However, before you tame the aluminum to your desired results, there are some bits of wisdom you must keep in mind before firing up the torch.
Aluminum poses a challenge just as it is. If you factor in the thickness of the metal piece you're working on, it will add an undue burden on you. So start first with mastering the baseline thickness and work your way up the gauge grade.
On the other hand, your MIG machine has a ceiling capacity in the thickness it can weld. If you take into account the standard configuration range, a typical arc MIG welder can handle a baseline of at least 14 gauge. The beefier the aluminum, the harder your MIG will work to melt it. So check the chart first and see if your MIG rig can handle it.
As an additional tip, working on thinner aluminum will require a more delicate touch. You'll need to switch from MIG welding to Tungsten Inert Gas (TIG) welding to successfully do so.
Aluminum comes with a lot of variations. To make welding more interesting, hunt for the most suitable type for MIG welding.
The 1000 series is a good workpiece for your MIG welding equipment for fabrication and sheet work. This type of aluminum is close to its pure form and is a fun material to play around with. Couple this with an 1100 filler metal, and you're set for a wonderful welding session.
Your shielding gas must be 100% argon when dealing with aluminum. This gas setup helps you handle the complexities of welding resilient metal. In addition, it enables your torch to fire the arc steadily and gives you clean passes on aluminum pieces.
Using a MIG torch for producing high-quality aluminum weld takes some effort to master. Nevertheless, it's an excellent way to hone a skill. On the other hand, a spool wire gun burns the filler wire better and produces a clean weld finish easier than your traditional torch. That's because it "sprays" the filler metal. And if you find the sweet spot of your MIG machine settings, the spool wire will deliver without short-circuiting.
Help the welding arc penetrate the surface by cleaning your aluminum workpiece before starting. The purpose of cleaning is to remove the oxide layer that prevents your machine from effectively welding the aluminum. Cleaning also removes any substances that may cause impurities to your final weld result. This increases your chances of getting a good result the first time.
Scrub the surface with a steel brush, remove any surface moisture with acetone, and strip the surface of oxide and hydrogen.
Expanding your expertise to welding aluminum can be a challenging task at first. It will feel like starting over with a handicap. But the tips and tricks provided in this article will help you discover your route to aluminum mastery. Once you get to a desired level of experience, you'll reap the rewards that aluminum can bring to your welding projects and your career.