Here is a link to a how-to article on another website:
http://dansresincasting.com/Ground%20foam.htm

Luke, thanks for sharing that article with us. Its ingenious, great stuff. Kevin

your welcome I found and the first thing I thought was post it on armorama.

here is another one:
http://www.2guyzandsumtrains.com/Content/pa=showpage/pid=10.html

Luke those are very interesting articles, but tempted as I am if my wife caught me using her blender for modelling purposes, I wonder what else she would be likely to want to place in the blender? A clue.......It would really brings tears to the eyes

John

garage sales
and to quote danpik (the guy who did the first one it's his model railroader forum name)
"Rmember!!!!!!! DO NOT USE A GOOD BLENDER. It won't be a good one when you are done. "

Open cell is like what a kitchen chair pad would have in it. (soft and spongey with visable little cells in it.) This will make good "coarse" ground foam.
Then there's closed cell-This is the stuff florists use to stick artificial plants in. When ground up, turns into a finner "powder" like texture for a finer grade of foam.
There is a medium grade of foam that is like GREAT STUFF foam insulation spray after it has dried.(some parts of car seats have this kind of foam) This is good for a medium grade foam.
NOW! If you followed that.....Your ready for the next step....GRINDING!!!
You need a heavy duty food processor with semi fine blades. Feed the foam into the FP and experiment with the differant textures you get from the differant foams and differant FP blades.(This takes a little practice and WATCH YOUR FINGERES!!!!!!!!!!!!)
Use cheap craft paint from a craft store to color the foam as it is turning in the FP.(again, somthing that takes practice.) Spread the colored foam onto a peice of newspaper to dry when finished. If the dried foam is still too coarse, you can run it back through the FP and grind it up finner.

Great links luke!