Shellac vs. lacquer

[Bill Ballard]

At 2:37 PM +0200 7/15/02, Richard Brekne wrote:
>Holy Christmas Bill... you used at least eight 67 cent words
>there... :) gets complicated for this Norwegianized mind of
>mine.

They cost me at least $4.95 apiece. You'll see a noticeable mark-up 
in the invoices I'm sending out. The big challenge to the internet 
economy is creating revenue streams out of all this digital traffic.

>If you want an idea of how Shellack is going to behave over
>time inside the hammer take a thick dense strip of felt (for
>example damper lift felt for the back end of grand keys) and
>soak a short strip of it in Shellack and let dry. The have
>fun playing around with it in as many creative ways as you
>can think of and check out how it reacts.

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.

>As for whether this whole process leaves the elasticity
>decimated or not I dont know.... try stretching the strip
>above and see how snappy it is ! Tho I have to wonder if
>your segmentation would like reaaaly be synomonous with
>chopping the felt fibers into a million short peices with
>one of those Japanese knife thingys. :)

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.)

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.

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.

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?

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.

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. 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 no ready for the opinions of 
others.

Bill Ballard RPT
NH Chapter, P.T.G.

"I gotta go ta woik...."
     ...........Ian Shoales, Duck's Breath Mystery Theater
+++++++++++++++++++++