Has anyone tried using this product to make anything? I used it last night to make some tree trunks and branches and it seems to work decently when modeling. The problem I have with it is that on the package it says that it dries and hardens by itself, but I let it sit overnight and while it did dry a little bit, it didn't dry and harden completely. It's still fairly soft and pliable. I don't want to put it in the oven because I already modeled the rest of the foilage onto the tree branches but I'm worried that it may never get fully hardened. Should I possibly put some watered down pva glue to solidify the outside of the clay?