In Defense of Bilon
By John Grant
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
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(Message sent Thu 1 Aug 1996, 02:28:17 GMT, from time zone GMT-0700.) |
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