My first Ampico piano rebuild (Marshall and Wendell Upright "A") was
done in the 70's with Polylon which I bought from Nelson Barden, of
Barden and Clark, who were doing mechanical music restorations in the
Boston area at that time.  I glued it with a latex(?)-based material
from them called "Thunder Over Paradise" or TOP, very similar to the
PVCE we use today.  (How the name Thunder Over Paradise was picked is a
story in itself.)

I believe that the Polylon material is actually polyurethane-covered
nylon cloth (thus the name poly-lon), derived from the raincoat
industry.   I have an old army officer's raincoat that seems like a
similar fabric.  I agree that my Polylon material has developed
pinholes in the corners, and I even had to replace the play/reroll
fabric because it flexed with a lot more wrinkles than the striker
pneumatics, causing the polyurethane to flake off.  However the striker
pneumatics are still playing as well as they did when new, in spite of
corner pinholes.

I believe that PPCo got on the bandwagon, so to speak, and developed
Bilon.  Polylon has a urethane coating on just one side, while I
believe that Bilon, as the name implies, has the urethane coating on
both sides of the nylon fabric.

Later in my hobby, about the early 90's, I did another Ampico piano
with the PPCo material, and it was not as good as the original Polylon.
So, being educated by good AMICA friends and by MMD, my Mason Ampico
"A" and my Steinway Duo-Art are both done with the (hopefully) best
traditional materials from Australia, which I bought from Mike Madeira.
I believe that Schaff now sells the Australian material also.  Bring a
well-equipped wallet when you go to buy it!

Pat DeWitt
Fort Wayne, IN