These are the small rocky outcrops that I made the other day for a game I'm playing tonight in D&D. They are made from Luke's Modelling Compound and took around half an hour to model, then a bit of drying time and then half an hour to paint over with washes, 2 browns and a black.
The larger pieces like the 2 above I put the compound over the top of some polystyrene scraps to save on materials.
I painted straight onto the plaster mix there was no undercoat at all.
Will do a step by step when I get the chance, but too busy at the moment, sorry. Probably next week now. I used mainly my hands and finished them off with only one tool, so not complicated at all.
What I like about then is that with only a few bits I can create a whole series of different looking caverns and tunnels without too much hassle.
Below are a whole series of slightly different looks to the basic cavern set up
Will let you know how they work out in actual game play.
And yes I am a friend of Luke's and work with him on projects just to be open and clear.