Here are some shots of my failed attempt to make my own hollow forms.  I spent the better part of a day

making a jig and ruining a good piece of plywood before I decided the end product was not going to be

accurate enough.  All in all it was a real pain in the butt.  I wound up ordering 15 and 25 foot radius

hollow forms from Luthiers Merchantile.  They are very nice and I highly recommend them.

This is the jig to hold the round piece of plywood that is supposed to become the hollow form

This shows the jig with the round hollow form and the track I made for the router.

This is the hollow form after I finally decided to give up on it.  I got it about half done.