Can you tell us how to test pneumatic cloth?  Is there a way to
know for certain that the pneumatic cloth I buy today will last
longer than two or three years?

We all know how much work is involved in restoring a player and the
sickening feeling it is to discover that all the work done will have
to be done over again because of materials that we thought were the
best are failing.

Why is it pneumatic cloth that dates from 1929 is excellent quality,
still in use and not leaking, while pneumatic cloth I purchased in
1994 leaked like a sieve in less than five years?  (Both cloths are
in use, in the same piano, under the same conditions.  The very old
cloth is excellent.  The new cloth deteriorated in a very short time
and had to be replaced)

What happened to the old formulas for making good rubber cloth?
Why can't those old formulas be found and used today?

I paid enormous prices for what I thought was the best pneumatic cloth
available that is now worthless.  When I applied the "new" pneumatic
cloth on various bellows, it tested tight and worked for awhile.  Then
something happened.  The rubber slowly turned hard and crumbled.

How can this phenomenon be predicted by early testing?  Does one have
75 years to test the quality of rubber cloth?

There was no guarantee when I purchased the cloth.  Why not hold the
manufacturers responsible for quality?  Perhaps if we all get together
and insist on a guarantee, or refuse to buy the materials, the
manufacturers would be more careful in producing higher quality.

Bruce Clark