I believe Sandy is right. It takes a while for the wood to completely dry. Not unless you kiln dry it. Still, even if you dry it, you may need some chemicals in the process, I am not sure though. I believe you will have to spend a lot of money for that matter, especially if you looking for a one piece, not a ply shell.
I heard that Peeves was able to make a shell before. That is out of multiple plies, if I am not mistaken.