Will Bondo Stick To Plastic? (Solved)

When you look at Bondo’s description on the official 3M page, they say that it should be used on metal, masonry, drywall, painted wood, and concrete. Plastic is not included on this list.

Considering how popular plastic is in the environment if Bondo were to be used on plastic, the manufacturers would have mentioned that in the description.

Bondo shouldn’t be used on plastic. Even though a couple of DIY enthusiasts use it to cover imperfections on plastic, it’s not the right product for such a job.

If you have a dent or scratch on a plastic surface like your car’s bumper, it can be tempting to use Bondo. After all, it works perfectly on metal. Why shouldn’t I use it on plastic? Well, the main problem is with adhesion.

will bondo stick to plastic

Does Bondo Stick to Plastic?

Bondo doesn’t stick very well to plastic. On metal, Bondo can stick for years without any issues. However, plastic surfaces can’t adhere well to Bondo.

Immediately when you apply Bondo over plastic, it will stick for a few weeks or even months. However, after a while, the Bondo will start to peel off. Using Bondo to repair plastic is only a temporary fix because it will not adhere properly for very long.

Eventually, you will need to use the appropriate techniques for repairing plastic bumpers. Even if you are using Bondo on plastic bumpers, the chances of it sticking properly are very slim.

Plastic bumpers are made using thermoplastic which doesn’t adhere easily to substances such as Bondo. You, therefore, have to look for other methods on how you can repair plastic other than using Bondo.

Why Shouldn’t I Bondo over Plastic?

Without a doubt, Bondo works perfectly when you use it to correct imperfections on metal. However, on plastic, it’s a different case. There are a couple of reasons why you shouldn’t Bondo over plastic. They include;

• Bondo Won’t Stick to Plastic

We have already explained that Bondo doesn’t stick very well to plastic. Unlike metal, plastic tends to have a very smooth surface.

When Bondo is applied on top of it, it has trouble holding on. For Bondo to stick, it must be applied on a rough surface.

That’s why when you are applying Bondo over metal. You are advised to scuff or sand it first. If you Bondo over plastic, it will peel off with time, and the damage you were trying to hide will be left naked.

• Plastic is Vulnerable to Temperature Changes

Other than Bondo not being able to stick to plastic, this material is quite susceptible to temperature changes. Plastic expands and contracts when exposed to high and low temperatures, respectively.

When Bondo is applied to plastic, it will cure and dry. When the plastic is expanding or contracting, the Bondo will eventually crack and become weak, causing it to fall off.

Because of these two main reasons, you should avoid applying Bondo on plastic. No matter how desperate you are to fix a dent on a plastic surface, there are better solutions out there.

We can only advise you to use Bondo as a short-term solution.

But when you consider the amount of work needed to apply the Bondo and cover it in paint. It’s better if you can invest that effort in a solution that works and offers long-term benefits.

Does Bondo Have Some Adhesive Properties?

Yes, Bondo is both a filler and an adhesive. However, it isn’t glue. Many people mistake Bondo for glue, and that’s why they assume it can be used on plastic.

When you apply Bondo on a surface such as metal, the polyester resin sticks to the metal. This is why it doesn’t come off easily. However, Bondo’s adhesiveness wasn’t meant to be used on plastic. This is why it doesn’t stick to it.

Because plastic isn’t a material Bondo was designed to adhere to, its adhesive properties are inapplicable in this scenario. To avoid issues in the future, avoid using Bondo on plastic.

Does Application Matter?

For Bondo to stick on a surface, it must be applied correctly. But in this scenario, Bondo shouldn’t be used on plastic. Therefore, how good or bad you apply it won’t cause it to stick. These are just one of those things that are incompatible.

But Some People Have Used Bondo on Plastic?

If you are the kind of person who enjoys research, you have probably come across posts that praise how Bondo works so well on plastic.

If you have been reading this review keenly, you will see that we have said Bondo doesn’t hold up very well on plastic.

When you apply it to plastic, it will stick, and you can paint over it. However, a couple of days or weeks after, you are going to notice peeling or cracks on the Bondo. Those who claim that Bondo works fine on plastic probably haven’t seen its long-term results.

Secondly, if Bondo were meant to work on plastic, wouldn’t the manufacturers have mentioned that in the description?

DIY enthusiasts are a creative lot. They are known to make the impossible possible. However, there are scenarios where no matter what you do, the outcome remains the same.

What Should I Use on Plastic?

Now that we have seen Bondo isn’t the best filler to use on plastic, what other alternative do you have? Plastic fillers are the best answer for repairing scratches and dents on the plastic. Unlike Bondo, these are specifically made of plastic.

Bondo has created a name for itself over the years in the auto industry. Whenever a person wants to hide a scratch, the first thing they think about is Bondo.

If you intend to use it on metal, there is no problem. However, if you plan to use Bondo on plastic, you won’t be satisfied with the results.

Most plastic fillers contain calcium, talc, silica, clay, wollastonite, and carbonate. These ingredients are formulated to work exceptionally well on plastic.

They stick very well on the plastic surface. They also don’t crack when the plastic expands. It lacks the drawbacks of using Bondo.

But, it is very similar to Bondo. The application process is the same. It will cover dents and scratches. Plus, it conforms easily to plastic.

Bondo may be considered an all-purpose putty, but if your objective is to conceal dents or scratches on plastic, you are better off using plastic filler.

There are many plastic fillers in the market, a popular example being the Isopon Plastic Bumper Filler. You must engage in thorough research when shopping for fillers. Reviews can help you identify plastic fillers that will withstand the test of time.

What about Body Filler?

Bondo won’t stick for very long on plastic. What about regular body filler? This, too, shouldn’t be used on plastic. Body filler is meant to be used on metal.

The problem with many people these days is that they perceive the instructions and labels on product packaging as decorations.

When you read the cans of most body fillers, they indicate the surfaces this product can be used on. There, you won’t find any recommendation that the filler can be used on plastic.

If you have somebody filler at home and your plastic bumper has been scratched, don’t be tempted to use it. Instead, head to the nearest store and get some quality plastic filler. This will stick just fine and will last for long.

Can Plastic Fillers Be Used to Fill Deep Scratches?

Yes, you can use plastic fillers on deep scratches. We would advise you not to use Bondo or regular body filler on deep scratches. These two are because they won’t stick to plastic. When used in large amounts, it will peel easily.

Before performing any repair on your car, it is vital to conduct a thorough assessment.

If the dents and scratches on the plastic are deep, you should evaluate between filling them and replacing the entire part.

In cars, for example, a plastic bumper with many deep scratches, it’s better if replaced than repaired with filler.

What Do Detailers Use? Bondo or Plastic Filler?

A reputable detailer would choose plastic filler over Bondo when working on plastic parts. However, not all detailers are created equally. Some will go with the quicker and easier option, which is to use Bondo.

If you are taking your car for repair, ask the detailer or mechanic what they use to repair dents on the plastic. This will ease your mind knowing that the product used is effective and lasts long.

Depending on how damaged the plastic is, your mechanic or detailer may convince you to replace the part.

How Can I Remove Bondo from Plastic?

Because Bondo doesn’t stick firmly to plastic, removing it shouldn’t be very hard. You can use sandpaper.

Alternatively, you can pry it off with the help of a screwdriver. If you have used Bondo on plastic in the past, take time to remove and replace it with plastic filler.

Was this article helpful?
YesNo

Leave a Comment