I stumbled upon this great website the other day,
http://www.pacificcoastairlinerr.com/volcanic_rocks/
They have a great tutorial for using ceiling tiles to create volcanic rocks / rockwalls.
I’m thinking about using this material for creating larger cliff faces on one of our sectional modules.
As you may have read we have used aluminium flyscreen and plaster of paris to create mountains and cliff faces. It was a very quick process and looks pretty good, but I have concerns that it may be a bit fragile for transport or knocks taken during general setup and storage.
Apparently the ceiling tiles are easy to shape as well as being light weight. So this could be a fairly low stress way to create a feature cliff face that can handle a bit of flex during transportation and setup.
Stay tuned!
Edit.
After a bit more looking around the site, I found this article about larger cliff faces / rock walls.
http://www.pacificcoastairlinerr.com/more_rocks/
Great advanced techniques for finishing off the scene too!