Ye Olde Inn

I have some white styrofoam - the kind that electronics might be packed in for shipping.

I have heard/read that you can't paint this. Is it true? If so, is there a way to paint it?

I have two pieces that could be PERFECT for creating two long dungeon hallways or a
cavern or narrow mountain pass or something like that.

Thanks.

you can paint it, just not spray paint it as its the chemical compressed gas that melts the foam, the same as super glue.
Best way is with some good old poster paint, maybe with a mix of sand to add texture or even just a dab of washing up liquid to break down the surface tension so it goes on better.
Usually the best thing to do is give it a quick once over with wall filler, this adds texter, is easy to paint over and makes it slightly stronger.
Also don't use super glue, they will react to release cyanide gas, use pva or a hot glue gun.

Oh almost forgot, take pics and show us when you are finished. Also a quick coat of watered down pva will help to protect it after you have finished, like a sealant.

Cool. Thanks a lot. I'm going to try and work on it soon. I've had the pieces sitting by the trash for about a month,
and I KNOW my wife is tired of looking at them.

If you have any questions just ask. This is one thing I do know about!

One question - any tips on cutting the styrofoam?

you can get a styrene cutter, but the easiest and cheapest way is with a wire stretched across a coat hanger connected to d cell batteries, why pay out when that is all it really is. Other than that you can heat up a knife. Make sure you do it outside or in a well ventilated room.

I'd also go with a hot-wire cutter. You'll get the cleanest cut, even if it is a bit jagged from uneven pressure as your hand guides it through like butter. If you think you can get away with a saw, be prepared for big mess of tiny styrofoam cells/balls. This also will likely produce very rough cuts. A sharp hobby knife (X-acto blade) is okay for small sculpting, but again some cells will likely flake off.

yes, wirecutter also melts the surface a bit, making it easier to paint.

also: LATEX paint! basecoat in latex, the stuff you paint on walls, and then you can paint any acrylic paint over it. There is a neat topic about making dungeon tiles with styrofoam somewhere on this forum.

or mix PVA in with your paint, cheap and effective!