I thought I'd share some general thoughts on things that were raised in this thread, concerning adding hardeners to hammers.
Concerning B72, it is an
acrylic resin, which has various uses including in conservation techniques (as a reversible adhesive, I believe). Ken Eschete was drawn to it because it was soluble in ethanol as well as acetone. His reason for wanting ethanol as a base has to do with speed of evaporation. Faster evaporation, as with acetone, causes a larger portion of the solute to migrate to the surface of the material that has been saturated, as opposed to staying deeper, as demonstrated by some experiments he had read about. When I asked Ken how B72 was different from acrylic (as in ground up plexiglass and the like), he said it wasn't different in any significant way, except for that fact that ethanol would dissolve it.
So that is what led Ken to propose using the material, not some magic difference in its effect, but simply the fact that it could be used in an ethanol solution, thereby leaving more of it deep in the hammer.
Lacquer thinner is formulated to slow evaporation. It is essentially acetone with various other, slower evaporating solvents added, to allow the lacquer to flow better on the surface, and to retard its evaporation so it won't have as much tendency to "blush" (caused by the cold created by the fast evaporation, condensing water from the atmosphere, I believe). So use of lacquer in lacquer thinner will also leave more of the hard material deeper in the hammer. Probably lacquer thinner could be added to "keytop and acetone" to retard its evaporation.
Shellac is soluble in alcohol of various sorts, and this would have the same effect. As to how the stiffening caused by shellac compares to that of nitrocellulose lacquer or acrylic, there are probably various opinions, but probably based on no actual rigorous experiments.
Applying any hardening material in a solvent to the side of the hammer will leave more of it within the hammer, and none on the surface, as long as you control how you apply it.
I guess I'll leave it at that, for now. Just some musings, in the hope of focusing thought on some of the important aspects of the materials and processes involved in hardening hammer felt.
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Fred Sturm
University of New Mexico
fssturm@unm.eduhttp://fredsturm.nethttp://www.artoftuning.com"We either make ourselves happy or miserable. The amount of work is the same." - Carlos Casteneda
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Original Message:
Sent: 10-19-2018 06:54
From: Philip Jamison
Subject: Voicing Up a Steinway M
Here is a link discussing denatured alcohol and solvent fumes. Post #6 is an interesting one. Clear Spring is not available near me, but I'd like to try it (for shellac, that is).
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Philip Jamison
Philip Jamison Pianos
WEST CHESTER PA
610-696-8449
Original Message:
Sent: 10-18-2018 19:13
From: Daniel Petrzelka
Subject: Voicing Up a Steinway M
Susan, agreed on all fronts.
I use the 190 proof I can buy on my regular visits to Portland, as its tougher to find in Washington after the liquor stores went public. The staff at the store I frequent in Woodstock always tell me I shouldn't be drinking this stuff, and nod politely when I ensure them its for high end instrument finishing.
It may be the larger quantities that use (larger bottles, with eventually more air space) that lead to greater moisture absorption by the shellac/alcohol solution. That is a great tip to store in a little glass dropper bottle for use in voicing hammers.
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Daniel Petrzelka
Mount Vernon WA
Original Message:
Sent: 10-18-2018 18:53
From: Susan Kline
Subject: Voicing Up a Steinway M
Hi, Daniel
That toxicity is the very reason I refuse to use denatured alcohol for anything.
The other reason to use 190 proof ethanol to make shellac is that it is so dry. It's water contaminating old shellac that makes it turn gummy. So, to make a voicing solution, I open a brand new bottle of Clear Spring, pour it over the shellac flakes which I've put into a small mason jar, very clean and dry. I immediately capt it with a fresh lid, and I keep the shellac in my kit only in a very tightly capped bottle (inside a ziploc bag.) I've found that old herbal tincture dropper bottles can seal tightly enough to preserve it. I've done tests like you describe on very old shellac (in the dropper bottle), and found that my 8 year old bottle of it was still as good as the day I made it.
YMMV, of course ... it depends on how dry the alcohol you use is, how good the bottles you store the shellac in are, how often you open them to use it, how long you leave them open, and how humid the room is.
One could, I suppose, go to extremes when conditions are humid -- get the action out onto an action cart or table, chalk mark the shanks of the notes you wish to juice, then open the dropper bottle, get some shellac into the dropper in your right hand, and put your left thumb over the bottle while you use the dropper in your right hand.
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Susan Kline
Philomath, Oregon
Original Message:
Sent: 10-18-2018 17:57
From: Daniel Petrzelka
Subject: Voicing Up a Steinway M
*One note with Shellac is that its curing hardness does change with age of the solution. In my guitar finishing I've found it wise to do a shellac test by allowing a small puddle to dry on a piece of glass/mirror and then scraping with your fingernail. After about 6-9 months it will usually start curing to a softer state (not as hard) than freshly mixed shellac.
It may be an immaterial difference for hammer hardening, but in my finishing work its key to test each batch. (unlike nitrocellulose lacquer which seems to have a nearly indefinite shelf life).
The low toxicity of shellac is wonderful if used with everclear - if using denatured alcohol ventilation is still a great idea.
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Daniel Petrzelka
Harrowed Strings
Original Message:
Sent: 10-18-2018 16:10
From: Susan Kline
Subject: Voicing Up a Steinway M
Ultrablonde shellac flakes in 190 proof ethanol is what I have experience with. The 190 proof "Clear Spring" from the liquor store is so dry it makes great shellac. Keep it tightly capped and it has an extremely long shelf life. Plus, both shellac flakes and ethanol from a liquor store are very nontoxic, so I can use it anywhere without worrying about fumes. While ultrablonde is not very colored as shellacs go, it does still have enough that you can see how far it has wicked in. So that is sort of good and sort of not good at the same time.
Mostly I put a few drops in the string grooves in the high treble. Sometimes I've needed to repeat that later on, and sometimes I haven't. I believe I did drip it in from both sides once, which I think worked okay, but I haven't done the side application enough to be able to predict the results.
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Susan Kline
Philomath, Oregon
Original Message:
Sent: 10-18-2018 11:57
From: Fred Sturm
Subject: Voicing Up a Steinway M
As long as we are taking alternative hardeners, you might also consider platinum blonde shellac flakes dissolved in alcohol. They dissolve much faster and more readily than B72. Available from
https://www.shellac.net. I've done some experimentation with it, but not enough to provide a formula for strength. It doesn't take much.
I'll also mention the option of applying hardener to the side of the hammer: set the action on end, swing each hammer individually, apply right at the tip of the molding. Observe how far it penetrates, keeping it below the surface of the crown by at least 2 mm. Apply to the other side as well, as it won't likely penetrate all the way through. This provides the equivalent of foundational felt density, substituting stiffness for density. IOW, it creates that little diamond shape of felt that you avoid disturbing when needling a hard pressed hammer in the traditional way, and leaves the shoulders flexible.
If more zing is needed, a little application directly to the crown will provide that.
Regards,
Fred Sturm
"Since everything is in our heads, we had better not lose them." Coco Chanel
Original Message------
I recently tried B72 for the first time, and was very pleased with the outcome. Don't think I had allowed three days for the pellets to dissolve in solvent, though. Sounds like things might go even better in the future when the pellets have had enough time with the solvent.
Alan
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Alan Eder, RPT
Herb Alpert School of Music
California Institute of the Arts
Valencia, CA
661.904.6483
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