Hello List,

   Recently, Pat Mularky mentioned a bad experience with some old Bilon
material.  This was followed by Craig Brougher with a general
skepticism of synthetic materials (which I share) but which would up
actually paying Bilon a effective compliment for its apparent
longevity.  Having been burned, as many of you were, by the disaster of
Perflex, I distrust synthetics in general, but I have a different take
on Bilon.

   If my understanding and information are correct, Player Piano
Company (PPC) only bought two lots of Bilon from its manufacturer.  The
two lots, which I will refer to as Lot A and Lot B are slightly
different, both in appearance and performanc e.  As near as I can
measure, both lots are 0.005" +/- 0.0005" in thickness.  (The catalog
gives its thickness as 0.0045".  Lot A has a very shiny appearance on
both surfaces and exhibits quite a bit of "stiction" or surface
stickiness.  In fact, when rolled or folded upon itself, it would
self-adhere with remarkable peel resistance.  In certain applications,
such as recovering Duo-Art accordion pneumatics, this lead to "noisy"
operation as the material flexed.  (I found that by pouring a bit of
talcum powder into the individual accordion chambers through the
nipples, shaking it around, and also dusting the outside surfaces, this
noisy operation could be eliminated.)  It is perhaps this surface
characteristic that caused a slight change in the specification for Lot
B, w hich has a much duller appearing surface, with a corresponding
reduction in "stiction".  The performance difference I have noticed
between the two is that Lot B, when used for striker pneumatics, will
develop a MINUTE pinhole right where the material folds in its double
"peak".  This happens fairly quickly, perhaps in as few as 1000 cycles
or so, BUT, once these few threads have fractured, the hole DOES NOT
enlarge and the leakage from so small a hole is absolutely negligible
from the system performance standpoint.  One of my oldest restorations
using Bilon from Lot A is now approaching the 20 year mark.  I still
see this instrument from time to time and the material looks to be in
perfect shape.

   It seems to me that scratching this or similar materials with a
fingernail is not really a relevant test as abrasion resistance is not
what is really needed in this application.  Long-term air-tightness,
flexibility, and resistance to deterioration from airborne pollution is
VERY important, and on these counts my experience is that Bilon
performs remarkably.

   After my initial experience with a small quantity of the Lot A
material, I purchased a fairly large quantity of Bilon from PPC.  By
that time, the Lot B material was being distributed.  When I heard that
Bilon was no longer available, I began to "hoard" what I had left of
it, reserving it for use on my own personal instruments.  At this point
however, I only have enough left for one standard sized stack, and so I
make the following open offer to Pat and anyone else who has any
sizeable quantity of the material they want to get rid of:  I will pay
$5.00 per square yard for Bilon from Lot B and $10.00 per square yard
(twice the catalog price) for Bilon from Lot A, minimum piece size of
one square yard (plus shipping).  Please let me know how much you have
that you want to get rid of.  Thanks.

-John Grant