[ Ref. "Replacement Grid for Ampico B Pump Regulator" ]

There has been much discussion regarding the Ampico Model "B"
and its curtain valves.  I have never seen any reference to what
I discovered when rebuilding my current Knabe Ampico "B", which
is a fairly late model bearing serial number 118178.

For reasons never before mentioned, the back side of both cloth
curtains show that a rather crude application of some coating
material was brushed on the fabric side of the pneumatic cloth.
This was definitely original factory work.

This added coating, over the years, caused a reaction with the
original rubber coating, causing the cloth to stiffen and also
to glue itself to the grid plate, but only where this coating
had been applied.

Was the use of this coating on the back side of the pneumatic
cloth curtain valves normal?  This is what caused the curtain
valves in this piano to fail.

Ken Vinen
Aylmer, Ontario, Canada