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Can You Use Oil Paint on Styrofoam?

There are several reasons that you might want to paint on Styrofoam. You might be working on a school project or an art project for yourself. When you are painting Styrofoam, you need to make sure you are using paint that won’t be harmful to the surface and will dry properly. 

So, can you use oil paint on styrofoam? While it might seem like a great idea to use oil paint on Styrofoam because the material is made out of oils and plastic, this type of paint isn’t actually the best. You will have much better luck with water-based paints like acrylic.

Styrofoam can be tricky to work with because it is such a porous surface. With an already tricky surface, you need to make sure you aren’t making it harder to finish your product. You shouldn’t use an oil paint on the surface of Styrofoam because it might unexpectedly increase the length of your project. Let’s read on to find out more!

Will Oil Paint Dry on Styrofoam?

Oil paint is notorious for taking a very long time to dry. Since drying time is an important factor for any type of project, it is important to understand whether the paint will dry on the surface or not. 

In the case of Styrofoam, oil paint will dry, but it will take a very long time. Since Styrofoam is porous, the paint will soak into all the different crevices in the surface. This can extend the drying time of the oil paint, causing the paint to be wet longer. 

Does Paint Melt Styrofoam?

Certain paints will melt Styrofoam when applied. Any paint that has some kind of solvent in it will dissolve and melt the Styrofoam. You should avoid using spray paints or oil paints that need solvents because the surface of the Styrofoam won’t be able to handle the chemicals. The surface will then melt and ruin your hard work. 

Styrofoam dissolves easily because it is basically a plastic pumped with air. This leaves the structure of the product open with pockets of air. The open structure also makes it easier for the Styrofoam to dissolve than regular plastic.

Paints that are water-based and do not have solvents will not melt the Styrofoam. These paints will be the safest to use to protect your Styrofoam from melting. 

My favorite and top pick is always Arteza Acrylic Paints. They have so many different colors, and the quality is amazing! I usually use Arteza Paints for all my projects.

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How Do You Waterproof Painted Styrofoam?

Styrofoam isn’t the sturdiest material, so protecting it and making it waterproof is a fantastic idea. You only need a few simple materials to waterproof the Styrofoam: a bowl, Plaster of Paris, a large paint brush, and a plastic tablecloth. 

Making painted Styrofoam waterproof is an easy process and won’t take long to complete. You need to seal the paint on the Styrofoam to make the whole thing waterproof.

First, you need to cover your workspace with the plastic tablecloth. This will protect your surrounding environment from dust and unwanted product. Protecting the area will also make cleanup a breeze when you are finished with the project.

Next, you will need to grab a large bowl and the Plaster of Paris. Mix together two parts of Plaster of Paris based on the instructions provided with the product. As you are mixing, make sure you are smoothing out any lumps that you are seeing. Any lump in the product can have a negative impact on bonding and create an uneven surface on the Styrofoam.

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As soon as you are sure that there are no lumps, you can start brushing the product onto the surface of the Styrofoam. Using a large paint brush, start evenly applying the Plaster of Paris to the surface of the Styrofoam. Make sure you are covering the entire surface and not missing any spots. 

After you are sure that you covered the entire surface, all you have to do is wait for the Plaster to dry. The container of the Plaster of Paris should tell you how long to expect the drying process to take. When the first coat is completely dry, apply another layer. It is highly recommended to add three coats to the surface of the Styrofoam.

As soon as all of the layers of Plaster of Paris are dry, the Styrofoam will be completely waterproof. You can leave your Styrofoam anywhere close to water and not have to worry about it being ruined by excess moisture.

Best Paints to Use on Styrofoam

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When you are painting Styrofoam, you want to make sure you are using the best paint for the job. There are several different types of paint available, so how can you be sure that you are using the best kind? Luckily, it is pretty easy to find the best paint for Styrofoam.

The best overall paint to use on Styrofoam is acrylic paint. This is because it is water-based, easy to work with, adheres to just about every surface, and is permanent once it is dry. Acrylic dries quickly as well, so you can move your Styrofoam soon after finishing the project.

Model and figurine paints are also a great option for painting Styrofoam. These are also types of acrylic paints, but they are designed to be used on and stick to small, sometimes porous surfaces. Model and figurine paints are easy to use, just like other acrylic paints. In some cases, they might even dry faster than regular acrylic paints. 

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Tempera paint is going to be another safe option to use. It is water-based and completely non-toxic. In fact, it is so safe that tempera paint is what you will see used in preschool and kindergarten classes. If it is safe for kids, it’s definitely safe for Styrofoam!

How to Seal Painted Styrofoam

If you don’t need your Styrofoam to be waterproof, you don’t need to use Plaster of Paris to seal it. You can use an acrylic-based sealant to ensure that your acrylic painting is protected. One of the best options for a sealant on Styrofoam is Mod Podge. Mod Podge is such a versatile product that can be used for several different projects.

The first thing you will need to do is ensure that the paint is completely dry on the Styrofoam. This will prevent any colors from running and ruining your painting. It is best to wait between 24 and 48 hours after you finish painting to add Mod Podge.

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Using thin, even layers apply the Mod Podge to the surface of the Styrofoam. This will allow each layer to fully dry, which is important before you add another layer. You should add a minimum of two layers, but you can add more if you feel it’s necessary.

Final Thoughts

If you are needing to paint Styrofoam, you need to make sure you are choosing the right type of paint to do so. Paints that include solvents, like spray paints and oil paints, are not a great option for Styrofoam because they can cause it to melt. Melting will ruin your project and your confidence. 

To prevent melting your Styrofoam, only use water-based paints when you paint the surface. After you have your painting finished, you will need to seal the surface to protect both your painting and the surface of the Styrofoam from scratches and dents. You can use Plaster of Paris or Mod Podge for the best results. 

Make sure to follow all my tips and recommended products to ensure your styrofoam painted project turns out great! Also, don’t forget to check out my other articles for all your painting Q&A’s. Happy painting! 

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