How to Paint Fiberglass Spoiler?

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Ever wondered why fiberglass spoilers are used in cars? Besides giving the car a freaking cool look, it plays with air in a bit “sciency” way so that your car gets enough grips when driving at high speeds. A scratched or chipped fiberglass spoiler might give you the grip, but not the cool look!

how to paint fiberglass spoiler
Photo by Grégory Costa from Pexels

Wait, before you leave your car at the nearest auto paint shop, take a look at our alternative that can save you a pretty penny! In this article, we are going to talk about how to paint fiberglass spoiler so that you can paint the spoiler yourself and save a lot of money. So, let’s crack the knuckles and get the creative hands ready!

Also Read: Acrylic Paint and Hydro Dipping

What Is Fiberglass Spoiler?

Before we start painting the spoiler, let’s understand what kind of stuff we are really dealing with. If you get some clear ideas about the spoiler material, i.e., fiberglass, it will help you understand which type of paint will be suitable for the job or how paints will behave if applied to it, and so on.

Spoilers can be made of different types of materials. Generally, they are made of ABS plastic, fiberglass, silicon, or carbon fiber. Different materials have different advantages. For example, fiberglass spoilers will be durable, carbon fiber spoilers will be lightweight, etc.

Today, our focus is on fiberglass spoilers only. Fiberglass spoilers are made with a combination of fiberglass cloth and thermosetting resins. Since a fiberglass spoiler is made of fiberglass cloth, you need to select the right type of paint so that it adheres to the surface well and lasts long.

How Do You Prepare Fibreglass Spoiler for Paint?

Fiberglass is a nonporous surface, so painting it is quite difficult here. Not all types of paint will adhere to this sleek surface. Spray painting is a better option compared to others. However, you need to make a good preparation so that the surface becomes suitable to hold the paint.

If the preparation is not good, the finish can peel shortly after applying the paint. So, you need to do the following to prepare your fiberglass spoiler for paint.


First, sand the spoiler well with 200-grit sandpaper. To make sanding easy, you can use a little sanding block so that you can reach the crevices. However, the block may not fit into all of them, so you have to rely on your hands here. Sand those areas using sandpaper while keeping your hand level and flat to the best of your ability.

Cleaning the Surface

After you are done sanding, first remove the dust and sanding residue. No need to use water yet. After the dry cleaning is done, you need to use a grease and wax remover to clean the surface deeply. If there are any traces of grease or wax left on the surface, the paint will not adhere to the surface properly.

To make the surface ready for paint, take a lint-free clean rag, apply some grease remover and wipe the spoiler. You should focus on this step because if there are any spots left, you may not notice them until you have completed painting the spoiler.

Next Read: Is Sanding Acrylic Paint a Good Decision?

What Kind of Paint Will Stick Well to Fiberglass?

Fiberglass is a smooth surface, so not all types of paint will work well on it. One of the main obstacles to painting fiberglass is to make the paint adhere to the surface. That’s why, from the wide range of paint types, you can apply only a few to this material.

To paint a fiberglass surface, you can use urethane, acrylic latex, or a blend of urethane resin and acrylic paint. Let’s look at the paints in a bit of detail.


You can use urethane for outdoor projects like painting boats. Urethane is durable and that’s what makes it suitable for outdoor works. So, the paint will not chip or tear easily.

However, to work with urethane, you need to use a chemical solvent and that can be hazardous to health. That’s why if you want to work with urethane, make sure to wear a protective mask.

Acrylic Latex

This type of paint will adhere to the fiberglass surface quite well. Acrylic latex can be easily applied and, unlike harmful paints, it does not have the risk of containing very harsh chemicals. So, you can use this paint on your fiberglass project without worrying about safety issues.

Urethane Resin and Acrylic Blend

This is another great option to paint a fiberglass surface. You will get the goodness of both polyurethane and acrylic paint from this blend. Since water-based polyurethane is used here, you don’t need to worry about hazardous chemicals anymore.

This blend adheres to the surface so well that you don’t even need to clean the old paint because it is capable of adhering to a dirty, old paint surface.

For your fiberglass spoilers, we recommend using spray paint. However, simply spray-painting is not enough. You need to follow a set of steps to make the paint adhere to the surface properly. And that’s the method we are going to teach you next.

How to Paint Fiberglass Spoiler?

After the material and the suitable paint for it is understood, and the surface is prepared well, we can move on to the heart of our article, which is painting the fiberglass spoiler. But before you start, here are the things you need:

  • Sandpaper
  • Paint Adhesion Promoter
  • Tack Cloth
  • Primer
  • Desired Spray Paint

Step 1: Preparing the Surface

We explained it earlier, but let’s give it a quick recap. First, sand the spoiler with 200-grit sandpaper. Make sure you don’t miss any spots. After sanding, remove all the dust and debris. Finally, clean the area with a wax and grease remover.

Step 2: Applying the Paint Adhesion Promoter

Since a fiberglass spoiler has a sleek surface, let’s begin with applying the paint adhesion promoter. It will help the paint stick to the surface well. Spray the adhesion promoter and let it sit on the spoiler properly.

You can follow the drying time stated by the manufacturer of the adhesion promoter. After the promoter is set, use a tack cloth to tack the spoiler off.

Step 3: Applying the Primer

You need to apply 3 coats of primer. Spray the primer in thin coats and try to apply the coats as evenly as possible. Cover the surface well. Make sure you give each coat enough time to dry before applying the next coat.

Step 4: Sanding Again

Once the top coat of primer is dried properly, you need to sand the surface again, but this time with 1200-grit sandpaper. Gently sand the spoiler. This sanding is just to make the surface better for applying the paint, so you don’t need to sand very roughly.

After sanding, you need to use the grease and wax remover again. Use a lint-free cloth to wipe the surface.

Step 5: Painting the Spoiler

After all the preparation and priming, now comes the good stuff! First, shake the spray can well. Now, start painting the underside surface of the spoiler with thin, even coats. You will finish the coats by reaching the topside. In other words, each coat will start from the underside and finish at the topside.

You need to apply four coats of paint. Make sure you keep the coats as even as possible and give each coat enough time to dry before going to the next coat. For drying time, follow the manufacturer’s information.

Step 6: Applying Clear Coat

Finally, after all that hard work, it’s time to preserve the paint. You need to apply an automotive clear coat. It will protect the paint underneath from harmful UV rays and mild scratches. You need to apply 3 to 4 coats of the clear. Make sure you give each coat enough time before applying the next coat.

Here is a guide for you:

What Kind of Paint Do You Use on Fiberglass?

As we said earlier, a fiberglass surface is smooth. So, you need to pick the paint wisely. You can use polyurethane, acrylic latex, or urethane resin and acrylic blend. These paints are capable of adhering to a sleek fiberglass surface. Plus, you can use other paints whose manufacturers clearly state that the paint is suitable for fiberglass.

Can You Paint Directly on Fiberglass?

If you want a color that will last long on fiberglass, you need to make good preparation before painting. This is more suitable for sleek surfaces because paint adhesion is a challenge here. So, if you want the paint to last long, we recommend you prepare the surface well first then apply the paint.

Final Thoughts

A fiberglass spoiler makes a car look cool as well as gives the car more stability while driving at a high speed. If you have a chipped fiberglass spoiler, you don’t need to ask professionals for help and spend a lot of money on it. You can follow our guide and repaint the fiberglass spoiler in your own style.

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