I recall reading about TMTerrain's successful experience with making realistic-looking boulders and rock outcroppings using a type of foam used by yoga and work-out enthusiasts. By scissoring or tearing chunks out of the foam you can create a very realistic rock type surface or texture and shape as needed.
Well, I have found a type of molding playdoh-type material called Molding Magic by Crayola (yes, the crayon company) that works just as well and is not very expensive (between and 3 and 4 bucks at Michaels for enough material to make a many moderate to small-size boulders). Basically, you can just tear away at the stuff, let it air dry OR you can let it air dry first then tear. I found the latter sequence to work better. Then you can use a combination of light and dark grey primer paints (like Krylon satin, interior/exterior) to produce the granite look. I even used the spray paint called Stone, to produce a mottled grey, black, white rock. It looks great and when air dried, it's super light weight (becomes rubbery when dry). Better than real rocks when it comes to storage.
Well, I have found a type of molding playdoh-type material called Molding Magic by Crayola (yes, the crayon company) that works just as well and is not very expensive (between and 3 and 4 bucks at Michaels for enough material to make a many moderate to small-size boulders). Basically, you can just tear away at the stuff, let it air dry OR you can let it air dry first then tear. I found the latter sequence to work better. Then you can use a combination of light and dark grey primer paints (like Krylon satin, interior/exterior) to produce the granite look. I even used the spray paint called Stone, to produce a mottled grey, black, white rock. It looks great and when air dried, it's super light weight (becomes rubbery when dry). Better than real rocks when it comes to storage.
