Polystyrene is a great material for making different projects. Indeed, it is very light and comes in many different sizes and shapes. To paint polystyrene, acrylic paint is the most suitable, because it will adhere best to the material. Since this is porous, you will probably need to apply several coats of paint to cover it. Work with a foam applicator and wait for one coat to dry before applying the next.
Part 1 of 2: select the paint
Step 1. Purchase an acrylic paint in the desired shade
Acrylic paint will be the most suitable for painting polystyrene, because it will not damage it and will adhere well to the material. Take a trip to the hobby store or search the Internet for an acrylic painting in the shade of your choice.
Step 2. Allow enough paint to completely cover the object
If you are only going to paint a few balls or a styrofoam cube, you will probably only need a small bottle, about 50g. For a larger work, buy a large pot, so that you have enough product to apply several layers.
If you're not sure how much paint you'll need, pick one that you can easily buy a larger amount, if needed
Step 3. Avoid spray paints
Conventional spray paint, such as latex or enamel, will eat away at the polystyrene. To keep your surface its shape and texture, avoid spray paints.
The chemicals in these products will damage the polystyrene
Step 4. Apply a filler if you are using a paint that does not adhere well
You can use a classic glue varnish or look for a product specifically designed to be applied to this type of material. Apply the polish with a foam applicator or a classic brush and let it dry completely before painting the polystyrene.
- Styrofoam varnish will fill in cracks and form a solid base on which to paint.
- Follow the instructions for the product you purchased so you know how long to let it dry and if you need to apply multiple coats.
Part 2 of 2: apply the paint
Step 1. Dip the applicator into the paint
Pour the paint onto a paper plate or scrap piece of paper, so you can easily coat your foam applicator with it. Immerse it in the paint, so as to take a small amount.
- Start by pouring a small amount of paint on the plate: you can always add more if necessary.
- If you don't have a foam applicator, a rectangular brush with soft bristles will also do.
Step 2. Paint the styrofoam
With the foam applicator, apply the paint in even brush strokes to the surface. You may need to dab the paint on the cracks and white areas of the polystyrene, so that the result is even.
Step 3. Let dry 10 to 20 minutes
Paints that you can use on styrofoam, such as acrylic paint, dry very quickly and will be ready for the second coat about 10 minutes later. Styrofoam is very porous: inspect it carefully after the paint is dry and see if you will need to apply a second coat to cover all the white spots.
Touch the object with your fingertips to see if the paint is dry
Step 4. Apply more coats until you are satisfied with the result
With the foam applicator, continue to apply even coats of paint, allowing each to dry before applying the next. Once you see no more white dots and the color is bright and even, let the object dry one last time.
- If your polystyrene surface is uneven, smooth it out with sandpaper before painting.
- To be able to easily hold your object when painting it, stick it on a skewer. Just know that this will leave a small hole in the material.