I used the 2 parts sawdust, 1 part flour, add water, recipe. Did this about a week ago. Just made up a little. Used too much water, so took about 3 day to properly. Turned out pretty good. Mix up a bunch (without the water), it'll get rid of a lot of sawdust for you, and if you give it to someone that thinks they can sculpture, it's a really cheap gift.
Or, you can mix up a bunch (no water again), and give it to a child care center, kindergarten, or similar, and it's a nice warm fuzzy gift, give the kids some fun, and a good way to get rid of sawdust. I'd screen it, for splinters, just-in-case.
I only mixed up about a small handful, just to try it. Seems like it would be pretty durable, one it's dried out well, and maybe painted. Not sure how it would sand, I'm thinking use finer sawdust, and it might be OK. I think too, with real fine sawdust, it might make a decent wood filler - but, I'd want to test it first.
JOAT Sarchasm: The gulf between the author of sarcastic wit and the person who doesn't get it.