I redid the stack on my 1912 Heinzman 88-note upright in 1995 using
rubberized cloth advertised for that purpose by PPCo. The job of
cleaning the old hide glue was not a simple one. I decided right
then and there that I would make fresh new boards from alder wood
should I ever have to do the stack again.
The finished job turned out to be quite a bit short of what I would
call a success. There was leakage all over and to play a roll I had
to pump like the dickens. Leaking valves were suspected, and there
were some, but the biggest problem turned out to be the striker cloth.
So apart it went again, and besides the few leaky valves I discovered
that the pneumatic cloth had stiffened quite a bit, and checking a
remnant left from the job and holding it against the light there were
pin size flaws all over. (I should have... why did I not... etc. etc.)
I decided right away to make new boards; I sealed them and, on the
advice of Craig Brougher, I used polyurethane coated nylon cloth,
gluing it down with PVC glue. With a table saw and a 12" planer one
can do wonders.
He stressed that I should glue the _shiny_ side of the cloth to the
wood. Had he not said that, I would probably have glued the buff side
to the wood. Checking the resulting peel and shear strength of the
joint after a couple of days, it does make a difference which side of
the cloth was glued down.
Having completed all striker pneumatics they are ready to be installed
(if I ever find the time). Obviously I tested the cloth for pin holes
and glue strength.
I am very impressed with the result so far and would rather make new
pneumatic boards than go through the dusty mess of getting whatever
glue removed. Besides that, when the boards are cut to size _after_
both sides have been sealed, there is no question of left over glue
on all (straight) sides. Before applying shellac I placed some tape
in the area where the hinge would be glued.
One learns all the time.
Albert de Boer