From Ty,
Hello,
Basically it was built using sheets of this stuff:
http://www.corkstore.com/Products/Cork- ... ts-2x12x36It's a large initial investment, but if you split it amongst a group it works out ok. The benefit is that you will end up with more craggy rock terrain than you know what to do with. Several 6x4 tables worth easily.
It may also be possible to get individual sheets at a Grainger, other specialist outlets, or if you are friendly with a contractor - you'd have to do some legwork to find out.
Anyways, we used 2" and 3" sheets. 2" being quite flexible as you can use it as is, or glue 2 pieces together for a 4" chunk and go from there. 3" is a nice midpoint as well.
First you cut out rectangles of cork to the approximate size/height you want the rocks to be.
Then you just attack it with a screwdriver or knife and whittle away the shape, careful not to make any areas too thin. it is cork and it is fragile.
when the shape is to your liking, mix up a vat of 60/40 wood glue/water and brush it liberally over the rocks - get it everywhere. Let it dry. This helps reinforce the semi-crumbly structures a good deal. You can then glue some sand in place for more texture.
Lastly, add a base of some sort. Then you simply spray layers of color as you see fit form the top down, you really don't even need to pick up a brush.
When you are all done, you will have lots and lots of unused smaller cork pieces laying around. These can be made into smaller rock outcroppings by hot gluing them to a base and treating them as above. Let nothing go to waste.
Hope this helps.
-Ty