Thanks, the model for the front glass works. I am not getting any more problems with the balls leaving the board.

However, I still can't use sprites for balls. It's hard to explain. They work, but they don't move as well, and they get stuck in the funnels. Models look natural and go through the funnels without a hitch. For both models and sprites I have the bounding box set to sphere. How do I make sprites perform like the models?