John Kleinbauer's way of making organ pipes reminds me of the
experiments I did about 30 years ago.  I made some pipes in almost
the same way, using 5/8" electric conduit pipe and corresponding
thicker wooden dowel material (beech wood).  I also made a bass pipe
out of 45 millimetre [1.77"] PVC rain pipe.

I have to admit that they worked fine for some time, but after a few
months it turned out that the wood inside the PVC pipes had shrunk to
an extent that both the fipple and the stopper had come loose again!

When you want to make pipes in the way John and I did, be sure to

1. Use wood that won't shrink too much (maple is fine, beech wood
is notorious for its shrinking properties);

2. Glue the block (fipple) firmly inside the pipe;

3. Leather the stopper.

I don't know which sizes of PVC piping is for sale in the USA, but here
in Europe it might be difficult to obtain PVC piping in sufficient
sizes to make a proper register.  Still, making flutes in this way is
great fun (mitering, for instance, can be done by using standard elbows),
and it's cheap!

Cheers from the Netherlands,

Hans van Oost