Can You Bondo Aluminum? (Explained)

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.

can you bondo aluminum

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?

Out of the many Bondo fillers in the market that have been formulated for aluminum use, only two stand out from the competition. They include;

1. Ease of Bondo® Filler

This is a product made by 3M. It is formulated for both home and auto use. If you are familiar with 3M products, you know that they don’t play around when it comes to quality.

Other than being made especially for aluminum, this body filler features extra strength. Therefore, it is super easy to spread; it doesn’t need a lot of effort and time.

Ease of Bondo Filler is still a 2 part filler that can be used on other surfaces such as wood, fiberglass, metal, and masonry. It is packaged with a hardener that gives you a working time of up to 5 minutes when mixed.

You need to take note of this to avoid disappointment when using the product. This product is sand-able and considering you are not using it on metal. You don’t have to worry about rust causing it to fall off after a while.

2. USC All-Metal Premium Aluminum Filled Auto Body Filler

The other Bondo product that will work exceptionally well on aluminum is USC All-Metal Premium Aluminum Filled Bondo.

This product has been around for a very long now, and over the years, it has helped many car owners with repairs. This product is special because it is formulated to work on galvanized aluminum and steel.

Other than that, it is easy to use and waterproof. You can use USC on all metals and surfaces such as fiberglass, primers, and even topcoats.

Unlike regular filler, USC can be powder-coated. It spreads pretty quickly, offers remarkable adhesive properties, and spreads relatively easily.

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.

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.

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