I have been reading this forum for several years and have had particular
interest in those articles addressing the quality of materials used for
restoration.  I have learned a lot from the professional automatic
musical instrument rebuilders who post on this forum.  In my professional
life I am a textile chemist with over 40 years of experience.  Because
of this background, I have been particularly interested to read about
the coated textile materials used for pneumatic motor applications.

I am currently employed by (but soon to be retired from) a company that
supplies specialty textile laminates to the outdoor apparel industry.
These products are designed for garments used in activities such as
mountaineering, backpacking, skiing, etc., and also military applications.

My company's policy is that the materials we sell must be thoroughly
tested to determine their "fitness for use".  This means that before
a product is sold it must undergo a series of tests to determine if it
will meet the end-users' performance expectations.  Often this requires
actual field tests to correlate actual performance to test results.

This brings me to my basic question: how do we as end-users of pneumatic
cloth know if the material we buy will perform for the expected 30+ years
in our instruments?  We can certainly visually inspect the cloth for
pin-holes and uniformity of the coating.  We can flex it by hand to make
sure it is supple enough.  We can possibly even measure air-tightness.

These simple tests, although indicative of some quality aspects, are
still no guarantee that the material will perform as expected.  Factors
such as adhesion of the coating to the textile substrate and its
resistance of the coating to the effects of atmospheric contaminants
such as ozone and oxides of nitrogen are well beyond the capability of
the average rebuilder to measure, but are important factors that could
result in premature failure.  So the responsibility of determining
"fitness for use" should, therefore, lie with the manufacturer and
suppliers of these materials.

Does anyone know what testing manufacturers of pneumatic cloth actually
do, or what testing suppliers demand of manufacturers before accepting
delivery?  I suspect that when demand for pneumatic cloth was high in
the heyday of player piano production, some sort of performance
criteria were demanded by the action manufacturers.

Does anyone know what they might have tested?  Should we ask for test
results from suppliers before we buy?  When one considers the amount of
work required to rebuild pneumatic instruments, some data to give some
assurance of the quality of materials and their fitness for use should
be made available.

Best Regards from Delaware, "The First State"
Paul W. Harris

 [ Paul, please describe how your firm would test a laminate cloth for
 [ its 'fitness for use' in a player piano.  One important requirement
 [ is that it should survive 20 to 30 years!  -- Robbie