Interesting idea.

Here is a link that may be of interest too.

http://www.dendroboard.com/forum/par...ake-rocks.html

It is 25 pages long so be ready to read but the best info is by the member HX starting about page 3. I think theis method could probably be modified to make hides in a similar manner, by casting over a bowl or the like. And you do not need to worry about water proofing afterwards...

Anyways, just a reference if others are interested.