How to Weld Cast Aluminum With MIG

Do you need to weld cast aluminum but don’t know how? Then you’ve come to the right place – read on to learn all about how to weld cast aluminum with MIG.

How to Weld Cast Aluminum With MIG

If you’re looking for a way to weld cast aluminum items, MIG welding is the tool of choice. It’s cost-effective and user-friendly, making it an ideal choice for home DIYers or professional welders alike. Whether it’s decorative pieces that are used as accents in your projects or quality aluminum products with extensive lifespans, knowing how to work with cast aluminum successfully can open up a whole world of possibilities.

In this blog post, we’ll cover everything from safety tips choosing the right supplies, and preparing your project before starting – all the way through different techniques you could use to finish off this exciting project. Let’s get started!

What are the Benefits of MIG Welding?

MIG welding is preferred for welding cast aluminum because it’s easy to learn, cost-effective and fast. It also has less spatter than other types of welding methods, making it ideal for home projects.

Additionally, you can use it with a wide range of metals, including steel, aluminum, and stainless steel. Another advantage is that MIG welding produces less smoke and fumes than other methods, making it a safer option for your workspace.

Now that you know the benefits of using MIG welding to weld cast aluminum, let’s look at some preparation tips before you start working on this project.

What Will You Need?

Before you start to weld cast aluminum, make sure you have the proper safety gear and supplies. This includes a welding helmet, heavy-duty gloves, and protective clothing. Be sure also to get a welding machine designed for MIG welding with an appropriate amperage rating.

You’ll also need the followings:

  1. A spool of aluminum wire
  2. Gas cylinder (for shielding)
  3. A grounding clamp and lead
  4. An adjustable regulator
  5. An appropriate tip size for your project
  6. A locking line clamps
  7. Flux-core welding rods (optional)
  8. And finally, your cast aluminum project

Now that you have all the necessary supplies, let’s get into the actual welding process.

10 Easy Steps on How to Weld Cast Aluminum With MIG

Step 1. Choosing the Right Supplies

The supplies you need for this project will depend on the type of metal you’re using and the complexity of what you’re trying to create. Generally speaking, however, most welders use a MIG gun with aluminum wire, an argon-based shielding gas bottle, flux-cored wires, and clean metal plates for practice welding.

welders use a MIG gun

Step 2. Setting up the MIG Machine

Once you’ve chosen your supplies, it’s time to set up your MIG welding machine and adjust the settings according to the type of metal you’re working with. Make sure that your voltage is appropriate based on the thickness of the metal you are using as well as the amperage level. This will ensure that you get a good weld without any issues.

Step 3. Preparing Your Project

Before you start welding, make sure that your project is clean and free from dirt or debris, which can interfere with the welding process. Also, use sandpaper or steel wool to remove any oxidation or rust from surfaces before starting. If your project has multiple pieces, make sure that they fit snugly together to avoid any gaps during the welding process.

Step 4. Connecting the Ground Clamp

The ground clamp is an essential part of the welding process as it provides a secure connection between your work and the metal you are welding. Once this has been connected, make sure that it’s firmly secured to the piece before beginning. It’s important to ensure that your ground clamp is securely connected in order to avoid any issues.

Step 5. Preparing Your Welder

Now it’s time to get your welder ready for use – set up your gas bottle and regulator, then attach the MIG gun to the machine using locking line clamps. When this is done, connect your spool of aluminum wire to the MIG gun and adjust the drive roll tension until it is snug but not too tight against the wire spool.

Set Up Your Gas Bottle and Regulator

Step 6. Setting the Voltage and Wire Speed

The voltage and wire speed are two of the most important settings when welding cast aluminum, so make sure you have them set at the right levels before beginning. A good starting point is usually between 20-25 volts for thin materials and 25-30 volts for thicker pieces. The wire speed should be set slightly faster than the arc strike rate to allow for a smooth weld bead.

Step 7. Testing your Welds

Before you start welding your project, it’s always a good idea to test out some practice welds on scrap metal or plates that are similar in size and shape to what you’ll be working on. This will help you get comfortable with the process and give you an idea of what to expect when welding your project.

Step 8. Starting Your Project

Now that you’ve practiced and tested out your welds, it’s time to begin working on your project. Make sure that your holding angle is consistent throughout the entire process. this will ensure a clean, even weld bead without any inconsistencies or gaps in the finished product.

Step 9. Finishing Up

Once you’re done welding, carefully inspect the weld for imperfections such as porosity or cold lapping – these can indicate a lack of penetration which could compromise the strength of your final product. If everything looks good, then you can move on to the next step.

Step 10. Cleaning Up

Once you’ve inspected your welds, it’s time to clean up the area and remove any slag or debris that may have been created during the process. Be careful not to scratch or damage the finished product when doing so. This step is important as it ensures a safe and professional finish to your project.

You’ve Inspected Your Welds

And that’s all there is to it! With these steps, you should now know how to weld cast aluminum with MIG and be able to complete projects in no time at all successfully.

5 Additional Tips and Tricks

1. Use a push technique with your wire feed to allow for better control and reduced spatter.

2. Make sure that your work area is clean and free of debris, as aluminum oxide can compromise the integrity of your weld and cause porosity.

3. Keep a steady and consistent welding speed to reduce heat input in order to avoid warping and distortion.

4. Use a backing strip or bar around your weld zone to provide additional support for forming a strong joint.

5. Before starting your weld, use a wire brush to remove any aluminum oxide on the cast aluminum’s surface. This will ensure that you get a clean and even weld.

Following these tips and tricks can help you create strong and reliable welds when welding cast aluminum with MIG. With careful attention to your welding speed, technique, and work area, you can always create a successful weld. Good luck and happy welding!

5 Things You Should Avoid

1. Using a wire brush on your weld area during welding. This can cause sparks to fly, which could compromise the integrity of your weld.

Using a Wire Brush on Your Weld

2. Adding too much heat to your weld zone, as this can lead to warping and distortion of the cast aluminum.

3. Do Not inspect your work area for debris and aluminum oxide before beginning your weld.

4. Welding too slowly can reduce penetration and weaken the joint.

5. Skipping any pre-cleaning steps, such as brushing away aluminum oxide from the surface prior to welding.

By avoiding these pitfalls when welding with MIG on cast aluminum, you will be able to create strong and reliable welds each time you use them on your projects.

What is MIG Wire for Cast Aluminum?

When looking for the right MIG wire to use when welding cast aluminum, look for a wire that is designed specifically for this purpose. An ER4043 or ER5356 aluminum alloy wire is a good option, as both offer excellent corrosion resistance and are easy to weld with.

Additionally, these wires can handle higher amperage settings than other types of aluminum wire, making them ideal for thicker sections of cast aluminum. Make sure to select the right diameter size for your application and consider buying a spool gun, as this will help ensure proper feeding of the wire in order to get a clean weld every time.

By selecting the right MIG wire, you can make sure that your welds are strong and reliable every time.


In conclusion, welding cast aluminum with MIG is both a challenging and rewarding experience. It requires knowledge of the correct welding parameters, consistency in the application of those parameters, and attention to detail to be successful.

Knowing how to weld cast aluminum with MIG can open up many doors for you as far as metalwork goes. You could end up customizing classic vehicles for fun projects or landing a job offer in an automotive or restoration shop.

With practice and patience, you could successfully weld cast aluminum with MIG and reap the rewards that come along with it. So don’t delay—give it a try today!

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Enrique Howard

Hi, I am Enrique. I started my professional life as a handyman and did a lot of external and internal repair of home and office with a little bit of electric and plumbing support. I have extensive experience in tools testing such as drilling, turning, milling, and non-conventional machining like EDM. So let me help you on your journey towards becoming an enlightened DIYer with amazing tools that you can use on your project.

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