What’s the best paint for expanded Polystyrene / Styrofoam

So you’ve created your landscape with expanded Polystyrene. Now to paint it. Don’t ruin your would be lush landscape by using the wrong paint. Here’s the best type of paint to use.

I typically build the landscapes around my dioramas and model railways with expanded Polystyrene (EPS), the white foam boards used in all manner of packaging, especially furniture and electrical goods. My wife now knows never to throw it away when unboxing and I’ve now amassed quite a little store of the stuff for future builds. In face, one of my sheds – in the above photo – is now filled with the stuff!

It’s easy to cut and shape, simple to glue – assuming you use the right glue for it – and very forgiving.

But once you’ve created your hills, fields, tunnels and other terrain with it, how do you cover it?

Where you’re covering up gaps or smoothing vertical surfaces, such as rock faces, plaster cloth or even straight plaster works well. For flat surfaces, such as fields and farm land, static grass or scatter can be just applied directly to it.

But sprinkling over scatter or static grass to the raw packaging foam can be problematic. For starters, the ghastly white often shows through the grass or lightening the tone of the greens and browns.

Instead, it’s recommended that you paint the Polystyrene sheet first to cover up the white.

And the best paint to use is good old acrylic or water based paints.

What not to use

Whatever you do, don’t use oil based, enamel type, and aerosol – spay – paints.

These are likely to contain or be based on solvents that will melt the foam.

I learnt this to my immense frustration a while back while making a river. I had a painstakingly carved and painted a foam river bed that looked perfect. I then added a few finishing touches  on a river bed using some enamel browns and left it to dry only to find, when I returned a day, later my river bed had turned into a geologically fascinating cave system, with dozens of holes and tunnels melted into it where the solvent had eaten away the expanded foam.

Instead, if I’d stuck to acrylic paints it would have been fine.

Which Acrylic paint to use?

Here the simple answer is any will do.

From the model paints of Vellejo, Army Painter and Citadel and artistic paints from Windsor and Newton to the bargain store kids paints, any acrylic will work.

Personally, for large landscape areas — which consume a lot of paint — I stick to the cheaper paints and water them down.

For small detail areas, I sometimes use Windsor and Newton as these have more variety and the colour descriptions are what you get. Cheap children’s paints can be particularly hit and mix in regards the colour shade you get. Artists paints also more economical than dedicated model paints.  The river bank scene here, was painted using these.

In summary, stick with acrylic paints and you won’t go far wrong but avoid enamels and aerosols unless you want a melted river bed look 🙂

> A final, personal, note: I spend a huge amount of time testing, photographing, writing and researching techniques for these articles and pay for all the running costs of MRE out of my own pocket. If you found this article useful you can support me by making a donation on my fund-raising page. Thanks and happy modelling, Andy.