I have seen many people who have built very nice pipes for calliope
projects from PVC.  These pipes do have a different style block
than an organ pipe, though, and are built on the whistle principal.
The Ragtime Automatic Music Co. makes all of their pipes from plastic
of some kind and paints them with a brass paint.  I have never seen
these pipes so I cannot say how they are made.  Just proves people are
trying all kinds of materials out there; I still would make them from
wood, though.

Thomas Grace
Chino, California