Doug,
I know Micheal's sells 3 or 4 variations of dry hard clay as I checked it out on their website. I am going to buy some tomorrow and try it, therefore I couldn't tell you how well it works or doesn't yet. I got it out of a Scott Hooper post, I believe.
I also know from many posts that folks use that epoxy sculpt, however, if I had a solution with out mixing up epoxy, that would be my preference.
http://www.michaels.com/art/online/s...%20clay&type=5
I'm sure someone more versed than I will chime in...
Regards,
Joe Ram