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How do you paint styrofoam without melting it?

Painting styrofoam can help bring your craft projects to life, whether you’re making architectural models, holiday decorations, or props for a school play. However, many paints will dissolve styrofoam if applied directly. The key is choosing the right paint and priming the styrofoam first. With the proper techniques, you can successfully paint styrofoam without any melting.

Why Does Paint Melt Styrofoam?

Styrofoam is made from polystyrene, a type of plastic. Many oil-based paints contain solvents that can dissolve polystyrene. Solvents break down the chemical bonds in the styrofoam, causing it to melt into a sticky, melted mess.

Some common solvents found in paint that can melt styrofoam include:

Mineral spirits Toluene
Xylene Acetone
Turpentine Naphtha

Even some latex paints contain a small amount of solvents that could potentially interact with styrofoam. The safest bet is to use paint specifically designed for styrofoam or to take some precautions when painting.

Choosing the Right Paint

When selecting paint for styrofoam, look for products specifically formulated not to melt polystyrene. Here are some good options:

Acrylic Craft Paint

Acrylic craft paint, sold in craft stores for decorative painting, works very well on styrofoam. It adheres nicely and contains no solvents that will eat away at the foam. Acrylic paint can be thinned with water as needed. It is available in tons of colors and finishes from matte to metallic.

One downside is that acrylic paint tends to be thinner than other model paints, so you may need multiple coats to get good coverage on styrofoam.

Model Paint

Look for polystyrene-safe model paints made for painting plastic scale models or miniatures. Brands like Tamiya, Testors, and Vallejo make acrylic model paints designed not to react with polystyrene.

These paints provide nice coverage on styrofoam. They come in many realistic colors like military greens, greys, browns, and camouflage tones that work well for model terrain.

Spray Paint

Krylon, Rust-Oleum, and other brands make spray paints specifically for plastic and styrofoam. Look for words like “for plastic,” “styrofoam safe,” or “polystyrene foam” on the label. The pigments and propellants are designed not to eat away at the foam.

Spray paint gives an even coat and helps paint get into all the nooks and crannies of irregularly shaped foam. Use light coats, allowing the paint to dry between passes.

Latex Wall Paint

Standard interior latex wall paint is safe for styrofoam as long as it does not contain solvents. Read the label carefully and do a spot test first.

Latex wall paint bonds well to styrofoam and provides good color coverage. It does not require priming first. Use a foam brush or roller to apply.

Priming the Styrofoam

For added protection when using paints not specifically made for styrofoam, it’s a good idea to start by applying a primer:

Acrylic Gesso

Gesso is a thick acrylic medium used to prime canvases for painting. Brush gesso directly onto styrofoam before painting with acrylics. The gesso helps seal the surface so the acrylic paint won’t dissolve the foam.

2-3 coats of gesso provide a nice, smooth surface for painting details. Let each coat fully dry before adding the next.

Spray Primer

After reading the label to make sure the spray primer is safe for plastics, you can use it to prime styrofoam for painting. Spraying creates a thin, even coating. Krylon’s Fusion spray primer works well for this. Let the primer fully cure before painting.

Mod Podge

Decoupage medium like Mod Podge can be brushed onto styrofoam to seal it before painting with oils or other solvent-based paints. Let it dry completely to create a protective barrier between the paint and foam.

Clear Packing Tape

For a quick and easy way to seal styrofoam against melting from paint, press clear packing tape or masking tape onto all exposed surfaces before painting. The tape acts as a barrier to protect the foam.

Painting Techniques

Here are some tips for getting great results painting styrofoam without damage:

Do a Test Patch First

No matter what paint you choose, it’s always smart to test it on a scrap piece of foam first. Brush a little paint in an inconspicuous area and let it dry completely. Check that the foam remains in good condition.

Start with Light Coats

Apply paint, spray primer, or gesso in thin, light coats to build up the coverage slowly. Thick, heavy coats are more likely to compromise or dissolve the foam.

Let Paint Dry Fully Between Coats

It takes paint longer to dry on foam than other surfaces. Be patient and allow each coat to dry completely before adding more paint. Rushing the process risks melting or ruining the foam.

Avoid Painting Directly into Corners

Paint has a harder time drying when flowed heavily into sharp styrofoam corners. Instead, keep paint coats thinner in these areas. Or brush just gesso or Mod Podge into the corners first.

Airbrush for a Smooth Finish

Using an airbrush is a great way to get smooth, even acrylic paint coverage without melting styrofoam. The light spray doesn’t soak the foam. Just be sure to select an acrylic airbrush paint.

Use a Foam Roller or Brush

Apply latex wall paint with a foam paint roller or soft foam brush. This gives the paint a route into the styrofoam other than direct absorption, helping prevent melting issues.

Avoid Solvent-Based Clear Coats

Skip the polyurethane or other solvent-based clear coats. These can interact with painted foam just like paint. Opt for acrylic spray varnish or gesso as a clear top coat instead.

Tips for Painting Styrofoam Terrain

Model railroaders and miniatures gamers often like to create custom styrofoam scenery and terrain. Here are some tips specifically for painting styrofoam for diaramas or gaming tables:

Carve and Shape First

Cut, shape, and glue together the styrofoam base terrain before painting anything. It’s much easier to work with unpainted foam.

Fill Gaps with Spackle

Fill any seams, gaps, or unwanted details with lightweight spackle. Let it dry completely before priming and painting.

Prime with Gesso or Tape

Seal the raw styrofoam with gesso, tape, or styrofoam-safe spray primer before painting details. This prevents later paint coats from melting into the foam.

Drybrush for Realistic Textures

Drybrushing coats lightly colored acrylic paints onto raised areas for simulated textures like stone, dirt, sand, etc.

Use Airbrush for Gradual Colors

Airbrush acrylic paints make it easy to layer colors and create blended effects like shadows or color gradients on styrofoam.

Add Turf, Plants, and Details

Glue on model train turf, plants, rocks, and other details to bring your painted styrofoam to life. These finishes cover any imperfect paint.


With the right paints and some simple precautions, styrofoam can be painted successfully without any melting. Protect the foam with gesso, tape, or styrofoam-safe primers before applying the color. Acrylic craft paints, spray paints, and latex wall paint all work well for coloring styrofoam. Model paints also stick to foam nicely. Avoid pouring paint into corners and work in light coats. Airbrushing and drybrushing create professional looking results. Sealing painted styrofoam with acrylic varnish completes the durable, beautiful paint job. With a little patience and the proper materials, you can paint foam easily.