>At 10:45 AM -0700 7/15/02, Susan Kline wrote: >>Now if you want the real gritty about what the stuff does to felt fibers, >>why don't you take a scrap hammer, soak it well in shellac, dry it out, >>vise it to something sturdy with the felt aiming upwards, and whack it >>with a mallet a bunch of times? Then take your knife, cut it open, and >>put thin slices on a microscope slide? > >Sounds like the test for ductility of music wire. I was contemplating >something on the single fiber scale, and which would compare resins. While this would be interesting, I'm not sure it would indicate what actually happens in a hammer as a piano is played. My mental image of a hardener is that while it probably coats the fibers some, it also is filling the gaps between them. The question in my mind is to what extent the various fibers are glued together, and how much force is necessary to free them afterwards. What I have against the keytop is that it probably glues them quite firmly together, and then stands up to playing too well, so that one ends up with a plastic fiber-reinforced block. Anyway, that's what they sound like to me. Spicky-ricky-ticky sound, if you get my meaning, and it only seems to get worse with use. >I should clarify. The elasticity I'd like to witness is that of the resin >by itself. Heck you could make a reinforcer out of watered-down TiteBond. >Its elasticity would be greater than keytop plastic. For me what >distinguishes these resins (lac bug stools, nitro lacquer, shellac and >keytop plastic) in their results is their springiness. (Oh, cure time is >also a major consideration, but in the scheduling of the work, not >necessarily in tone quality.) Springiness -- but also how much sound they absorb? There's that trick of using a drop or two of white glue on wires in the duplex section, to tone down the jangles. People have talked about the white glue changing the pitch of the duplex section, so it ends up away from major overtones; I can't say if this is happening, but I suspect that the smoothing of the tone is due to the rubbery dried white glue absorbing energy. So, while the TiteBond, being rubbery when cured, would be springy, I doubt that that would make the tone springy. >I seriously doubt there is any chemical reaction between the felt fiber >and and the resins which would degrade the fiber (and specifically, its >elasticity). The behavior of the combination i would bet is entirely a >mechanical matter. I suspect that you're right. However, if, for instance, part of a piece of clothing is well impregnated with bubble gum, would it matter whether the individual fibers were degraded? The behavior of the whole fabric is degraded, in a way difficult to reverse. >Under a powerful microscope, coat a single fiber. The fiber's springiness >is a known factor. The resin coating stiffens the fiber, making it slower >to bend under a deforming force (ie. collision with taut music wire). But >there's a big difference in how that fiber will return from the >deformation, based on the elasticity of the resin. I'd like the resin with >the greatest elasticity. Any coating can stiffen the fiber, I'm looking >for one which will contribute some of its own elasticity to the fiber, >after reducing the fiber's elasticity. Interesting. Keep us informed ... >Yes the breakdown is a significant determinant in the long-term prospects >for sound. Thanks to Richard for bringing this up. Imagine the resin >coating as a sheath. Its brittleness/elasticity will determine how its >will survive the flexing which occurs with each hammer strike. (Certainly >that flexing is likely to exceed the elastic limits of the resin mainly at >the strike point.) The segmentation I was exploring happens when the >flexing overcomes the resin's limits. At that point, wouldn't the coating >have fractured into segments. And now, coating the fiber not as a single >sheath but in many short segments, wouldn't it it have lost the original >stiffness it had as an integral whole sheath? Would its effect on the >fiber now mainly be limited to its mass, now clinging on to the fiber i >separate chunks? I think I would prefer a substance which breaks up and doesn't cling tenaciously to the fibers, but shatters loose instead. I'd rather not have the fibers smothered. Also, wouldn't the weight of small segments tend to break the fibers? I'd rather keep the fibers long and closer to their original condition, ready to be reinforced again, if need be. One problem with keytop is that it seals the hammer, so that subsequent applications can't penetrate to the middle anymore. An aging shellac, turning to dust inside the hammer, sounds more likely to allow something to get into the hammer, if need be; and it might just rejuvenate if re-wet with alcohol. >This is what pricked up my ears when Richard talked about the warming of >the sound as resin breaks down. I'm actually looking forward to this >process with shellac, because I haven't noticed it with keytop plastic. I'm looking forward to this, as well. Do keep us informed on how this piano does over time. >At 10:45 AM -0700 7/15/02, Susan Kline wrote: >>P.S. A blow-by-blow of your return visit to voice that set of hammers >>would be very welcome! I've used shellac for voicing, but never for >>building up a new set of hammers from scratch before. > >I will probably do the report tomorrow night. Tuesday is one of three >nights per week during the summer when I have two concert running, 45 >minutes drive apart. > >Briefly, this is a D with the whole nine yards done last year (I did a new >action with complete Stanwood), sitting in a concert shed >(http://www.svac.org/2002_final/wed.html), with a theater stage and >proscenium. You don't do things by halves! >I didn't push the reinforcing too hard last season, as I'm a firm believer >in the "work-hardening" of the strike point. But the time hard come to >make the piano project. So from that standpoint, the shellacing is part of >the initial set-up. I got over there yesterday and found the piano much as >I remembered it from the week before (and anticipated finding it). So 1.5 >hours of loud voicing (with Zen Reinhardt's "racket-ball"), mezzo, then >U.C., and finally quiet voicing. The piano is now ready for the opinions >of others. Sorry, I missed Zen's "racket-ball" ... how does this work? And what is U.C.? And what was your opinion as you worked? How did it respond to your voicing? Have you had a chance to stand out in the hall and hear it played? Are these Steinway hammers? >Bill Ballard RPT >NH Chapter, P.T.G. > >"I gotta go ta woik...." > ...........Ian Shoales, Duck's Breath Mystery Theater >+++++++++++++++++++++ Me too! After four days (blissful, really ...) of tuning a C&A S&S D (142... fantastic piano!!!! and much enjoyed by six or seven really lovely pianists)(L'Isle Joyeuse! Rachmaninoff Preludes, Brahms Rhapsodie, Gottschalk 4-hands, Stravinsky Sonata, Dvorak songs, Dett pieces I hadn't heard before, etc. etc.) I get to give a Betsy Ross a set of elbows. It all is part of the deal, it all is worth doing ... Susan
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