In the past I have usually used plaster or celluclay on wood boards for a base with a diorama. I've heard that extruded foam insulation board is light, carveable, and good for use as a base. I've had no luck finding it though. I've tried Lowes, and several craft stores, but no luck. Where can one find this stuff?

You can use the pink foam boards used for insulation or for a really dense foam use the blue marine foam found at most boat supply shops. Hope this helps.
cheers,
Bryan

Sometimes hardware stores dont carry the blue marine foam,, but seems Lowes should have had the pink foam.. ask for Polystyrene extruded foam insulation ( owens corning). McClendons Hardware carrys it.
I use the 1" thick. Cheaper than the thicker pieces and you'll prob have to buy a sheet anyway. If you need higher elevations than the 1" pick up some 1 1/4" drywall screws. Great for securing the pieces together in conjuction with white glue.. Good luck

Bryan and Kankali,
Guys, thanks for the heads up and suggestions. I drove right by McClendons and didn't try there. I will now.

Thanks again.

Kancali,
Sorry about the misspelling.

I use the Pink Foam Board all the time... so here are a couple of tips...

1) The stuff is waterproofed on the surface, so if you are going to be attaching plaster to it, first you should scuff up the surface... I usually gouge a few spots with a screwdriver, or my thumbnail. This will allow the water-based plaster something to "grab". Don't want your terrain to seperate a year down the road!

2) This is a great product for diorama builders. A 4ft x 8ft. sheet weighs about 3 lbs so it can be easily handled and stored. It sells for around $10 per sheet here in Dallas at Home Depot.

3) The product is easily cut and shaped with a razor blade or box cutter

Another option is to use the DARK green styrofoam from the floral section of your craft shop. NOT the lighter green "water-absorbant" soft foam, which crumbles to the touch. i buy a 2x4 foot section for about three dollars at Michaels, and as it is more honeycombed than the pink stuff, plaster and celluclay hold to it perfectly as is. It is also easily shaped (troughs, ditches, hills, holes and depressions, etc.) with your thumb and a little pressure.

Good luck!

After reading your post about difficuly in finding this product I did a web search for Owens-Corning, they have the ability to give you pink board dealers in your geographic area on the company web-site. Provived you want to go the pinkboard route. HTH

Gadzooks!!!!!!!!!!!!!!!!!!!! I was not aware of this. I've used the pink foam board for my last couple dio's and plopped drywall mud or plaster directly to it without roughing up the surface. I will certainly follow the above advice in the future, but for now I'm holding my breath.

Steve

Wow, thanks for all the tips and info. Much more than I had expected. I really appreciate it.

The pink stuff has a thin plastic film on the surface. Just peel it off and gouge a few anchoring holes to help the ground material stick.

Sealhead

There was a post of someone from Europe that carved a beautiful building with a building foam material. I've been waiting for his "how to" article with no luck. Any ideas?