People have been using Bondo on nearly all types of surfaces. Therefore, if you have always wondered whether it’s okay to use Bondo on aluminum, here is an article that has been dedicated to answering this question.
As modern cars shift to aluminum from steel, it’s imperative to know whether one can Bondo over this material.
Bondo can be used on aluminum. It can hold up pretty well as long as you get the prep work done to perfection.
However, even though Bondo does a good job at filling holes and dents in aluminum, another product works much better. That product is an Aluminum Filled Auto Body Filler.
For those of you who have been detailing cars for a while now, you can testify to the wonders of using compatible products. In the DIY world, trial and error is often the order of the day.
People mix different products, and sometimes, they work. Other times, it’s a total mess. This is the case with using regular Bondo on aluminum.
Considering that most car bodies are made of steel, people never really had any issues using Bondo.
But now that aluminum is increasingly becoming popular, people need to shift to aluminum body filler which has been strictly formulated to work on such surfaces.
What’s So Different about Aluminum Body Filler?
The first and perhaps most important difference is that it’s reinforced with aluminum. This ensures maximum compatibility. That’s not all.
It is reinforced with aluminum, making it easier to spread and giving it extra strength than regular Bondo. Aluminum body filler features a fast-drying formula that can take at least twenty minutes to dry.
There is one similarity between aluminum body filler and Bondo, which is that they both can accommodate cosmetic repairs. That is, you can anchor or drill into them.
Going back to aluminum body filler, this product is compatible with all types of metal other than aluminum. It can also be used on masonry, fiberglass, and other metals.
As you can see from above, even though it’s safe to use Bondo on aluminum. You will enjoy more convenience and better results if you use a specialized aluminum body filler.
What is the Best Bondo for Aluminum?
When selecting a body filler for aluminum surfaces, it’s essential to choose products specifically formulated for optimal adhesion and durability. Two notable options stand out in the market:
1. Bondo® Extreme Metal Reinforced Filler
Manufactured by 3M, Bondo® Extreme Metal Reinforced Filler is designed for both automotive and home repairs. This two-part filler is reinforced with aluminum, making it suitable for applications on aluminum, metal, fiberglass, masonry, and wood surfaces.
Key Features:
• Aluminum Reinforcement: Provides added strength and durability.
• Versatile Application: Adheres to multiple surfaces, including aluminum.
• Work Time: Offers a working time of approximately 3-4 minutes after mixing.
• Curing Time: Sandable in as little as 20 minutes.
• Paintable: Compatible with most paint systems.
Note: While this product is suitable for aluminum, it’s essential to follow proper surface preparation techniques to ensure optimal adhesion.
✔ Aluminum-Reinforced Strength – Infused with metal for added durability and superior adhesion to tough surfaces.
✔ Drill, Tap, or Anchor – Once cured, this filler can be drilled or tapped—ideal for both structural and cosmetic fixes.
✔ Quick Sanding Time – Ready to sand in just 20 minutes, speeding up repairs and refinishing.
✔ Rust-Proof Performance – Metallic finish won’t rust, unlike traditional body fillers.
✔ Multi-Surface Use – Bonds to metal, wood, masonry, and fiberglass—perfect for auto and household repairs.
2. USC All-Metal® Specialty Body Filler
USC’s All-Metal® is recognized as the original aluminum-filled automotive compound. It’s formulated to repair metal with metal, offering excellent adhesion and workability.
Key Features:
• Aluminum-Filled: Provides a metallic appearance and rustproof finish.
• Versatile Use: Suitable for steel, aluminum, fiberglass, wood, and more.
• Drillable and Tappable: Once cured, it can be drilled or tapped.
• Waterproof: Offers resistance to moisture, making it ideal for various environments.
• Powder Coatable: Can be powder coated after curing.
Note: This product is particularly beneficial for restoration work and classic car repairs due to its strength and finish.
✔ Aluminum-Filled Formula – The original metal-based body filler trusted for decades in professional restorations.
✔ Built to Bond – Delivers outstanding adhesion to bare metal and more—can even be drilled or tapped after curing.
✔ Rustproof & Waterproof – Resists corrosion and moisture, making it ideal for long-term durability.
✔ Restoration-Ready – Perfect for classic car repairs and high-end restoration work where strength and finish matter most.
How to Bondo Aluminum?
You have two choices when it comes to applying Bondo over aluminum. One, you can either use the good old-fashioned Bondo. Or, you can go with an aluminum-filled Bondo.
The latter provides more decent results since it is compatible. Irrespective of the type of Bondo you decide to go with, you have to be keen when it comes to application.
Aluminum isn’t built like steel or other types of metal. It doesn’t have shape memory. That means that once it suffers damage, it will not return to its original shape.
For it to do so, you need to use certain techniques. With that in mind, here is a guide on how you can Bondo aluminum.
✔ Fast and Reliable Repairs – Perfect for filling dents, rust holes, dings, and scratches, this original formula body filler is ideal for DIY and professional restorations.
✔ Quick Curing Time – Mixes easily with the included red cream hardener and dries in just 20 minutes, letting you sand and paint the same day.
✔ Smooth, Non-Shrinking Finish – Lightweight, spreads evenly, and won’t shrink or crack—great for prepping panels before paint.
✔ Versatile Surface Compatibility – Works on steel, aluminum, fiberglass, wood, and even concrete—not just for cars.
✔ Visual Mixing Guide – Salmon color appears when filler and hardener are fully blended for confident application.
Step 1 – Heat the Affected Area
You may be wondering what heat has to do with Bondo. Even though Bondo is a body filler, it should only be applied to scratches or dents that are not more than a ¼ inches deep.
This is where the heat comes in. When you warm the dented area with a heat gun, this causes the aluminum to loosen up. Therefore, if there was a dent, the heat should restore the Bondo to its original shape.
Step 2 – Cool Down the Heated Area
Heating alone isn’t enough to restore dents on an aluminum surface. You need to cool it down. You can use compressed air.
Or if that’s not available, a cold, wet rag always does the trick. But it should take longer. Once the surface is cooled down, the aluminum should be restored to its original shape.
Step 3 – Introduce Stud Pulling
Stud pulling entails the use of metal studs to remove dents from aluminum. This process should be used when the above fails. Before pulling the studs, you should sand the area first.
Step 4 – Apply and Spread Bondo
Once you are done with the above, it is time to apply and spread the Bondo. Using your Bondo of choice, pick a plastic applicator pad and spread it till you get a smooth surface. After spreading the Bondo, it may not be very smooth.
That’s where sanding comes in. You can sand afterward using fine sandpaper. That should leave you with a smoother finish.
Remember always to clean the area you want to Bondo thoroughly before application. Sanding also can help with promoting better adhesion.
Repairing dents and scratches on aluminum using Bondo is slightly different from what most of us are accustomed to. This is because of the properties of aluminum.
You need to try and pull out a dent first before applying Bondo because using too much may cause the Bondo not to stick well. If you don’t feel up for the task, it’s advisable to take your car to a professional detailer.
Does Bondo Cause Aluminum Corrosion?
We all know that Bondo may cause steel to corrode in some cases. This happens when air and moisture find their way through open spaces.
With aluminum, it’s a different story. This material is resistant to corrosion. Therefore, no matter how much moisture or air passes through, you will never have to worry about corrosion.
Does Bondo Stick to Aluminum?
If you are using aluminum-filled Bondo, then you have nothing to worry about. Since it should hold up pretty well. The same also applies to regular Bondo.
We are recommending aluminum-filled Bondo over the regular one because it is formulated for aluminum surfaces. This promotes compatibility.
Another issue that you have to take note of is that Bondo doesn’t stick so well on smooth surfaces. If the aluminum surface you want to spray Bondo on is smooth, sand it first.
This should ensure better adhesion. For body filler to stick, you can use 180-grit sandpaper.
Is Aluminum Repairable?
Even though dents on aluminum tend to be harder to repair, it is still possible. We have already taken you through a quick guide on how to go about that.
Aluminum-filled Bondo plays a crucial role in the repair since it smoothens the surface giving your vehicle a much more appealing finish.
Will Bondo Stick to Painted Aluminum?
It can, but it won’t hold on for very long. Painted aluminum is very smooth, and that will lead to adhesion issues.
However, if you rough it up a little bit, the surface will be much more ideal for Bondo to stick to. Never forget to sand aluminum before spreading Bondo.
Should I Bondo Aluminum or Take It to an Expert?
This depends on your knowledge, skills, and resources. Spreading Bondo over aluminum is a project that shouldn’t take up much of your time. Plus, it’s pretty easy.
The only problem with aluminum is pulling dents. At times, heating and cooling may not work. And it’s not everyone familiar with stud pulling.
If you have no knowledge or skills, we advise you to take the car to a professional auto body shop.
These guys won’t only use aluminum-filled Bondo, but they have all the tools required for such a task. It may cost more, but the result will be appealing and flawless.