Randy, the stuff you have described in the 130114 MMD is almost
certainly Bilon, which was marketed exclusively by Durrell Armstrong at
Player Piano Company in the '70s and '80s and was assigned stock #47.
IMHO, it was the greatest stuff ever sold for striker pneumatic
covering.  As I understand it, there were only two production runs of
it ever made.  The first run had a semi-gloss sheen on the plum-colored
side and had a very pronounced, pungent odor, probably from the
plasticizer chemical component.  It also made the surface noticeably
sticky, and I typically would dust the recovered pneumatics with talcum
powder or cornstarch to reduce that stickiness.  Probably because of
this defect, Durrell had the formulation changed for the second
production run.  The surface had more of a matte finish and the odor
was reduced, but still noticeable.  I have no idea how much of either
run was produced, but it was probably in the low thousands of yards.

Functionally, I found that the pneumatics recovered with Bilon would
fairly quickly, say a couple thousand cycles, develop a very tiny
pinhole at the point of the double fold.  However, the hole would never
get any larger, and its extremely small size resulted in negligible
leakage.  I have customers with Bilon-covered pneumatic stacks that are
approaching thirty-five years old that are still going strong.  Storage
conditions can be problematic, as apparently under certain combinations
of temperature, humidity, and the pressure from rolling/folding it, the
cloth (particularly the early production cloth) can stick to itself and
pull away the airtight layer when you unroll it.

I was never able to ascertain the manufacturer of the cloth, and unless
some former employee of PPCo knows, and is willing to share that
knowledge, Durrell might have taken it with him to the grave.

Durrell did write an article that appeared in the 99.06.14 MMD
( http://www.mmdigest.com/Archives/Digests/199906/1999.06.14.08.html )
that is an interesting read about the manufacture of pneumatic cloths.
But it does not shed much light on Bilon itself.  I, for one, would be
willing to go in with other interested restorers to do a third
production run of Bilon, if the original manufacturer can be identified,
is willing to re-open the production line, and wouldn't insist on a
100,000 yard minimum.  Anyone?  Anyone?

John Grant