Sculpting Simulated Rock Please Help


Sr Member
At my work, we are going to build a scale model Mars Rover and a Mars Landscape to roll it on. What is a good material to sculpt simulated rock out of? Enough to fill a small office.

I watched that documentary on the Star Wars Revenge of the Sith DVD, "Within a Minute" and at 58:00 into it they show Lorne Peterson sculpting and chiseling some lightweight substance, but he didn't name the material. Anybody know about this?


Well-Known Member
you could use several things for ground work

insulation foam sheet like the pink or blue stuff used to insulate homes it cam be found at most home improvement stores. it carves nicely with a sonz hand saw, or better yet a hot wire foam saw or hot wire knife these can be found at the micro mark website.
another item is urethane expaning foam you can make some quik dirty molds using woodland scenics but you would have to coat the molds with a release agent first.
another idea is to use cardboard strips stapled together in the shaps you want kind of like a lattice work, then cover with newspaper sprayed with diluted pva glue (elmers or similar)

hope this has been informative and of some help


Less than Super Ostrich

Well-Known Member
I use the foam used for planting flowers... you can find it in blocks at your local hobby/craft store. It cuts very easily. They you coat it with some sort of diluted spackle, putty, etc.... I use Durham's water putty. Best stuff in the world.


Well-Known Member
If you need the finest detailing and realism, this is the stuff.

But it's costly- a room full would be outrageously expensive - this is a similar material to what's being used in the SW doc.

Good luck.


Chris Martin

Well-Known Member
The quickest and cheapest for the amount you want is just carve some expanded polystyrene blocks roughly into shape then spray them with water with one of the those plastic hand pump misting sprays. At the same time throw cement powder or plaster powder at them so it sticks to the wet surface (cement powder seems to work better curiously). You can spray more water and throw more powder until you have what you want. Let them dry and then spray them a suitable colour or you could precolour the cement powder with coloured powder designed for colouring cement. We've made huge rock faces in less than half a day this way. It's quick, cheap and easy.
A) Whats your definition of realistic?
B) Whats your time frame?
C) Whats your budget?

There's a million ways to skin this particular cat.

-Gordon (professional spfx prop builder for 15 years)