The OP and discussion is focused on acetone/plastic. Ethanol reacts with the hammer and tone differently than acetone, as per Ken Eschete's work on the effect of flashing speeds on where the plastic ends up residing in the hammer. With B-72 (which I do not think is keytop but I think somewhat similar) the acetone, seems to bring the plastic out to the hammer surface as it flashes, leaving the solids on the surface of the hammer. Same B-72 but in ethanol, does not flash the same way, and the plastic remains deeper in the hammer, and more dispersed.
In my own experiments with B-72 in acetone and ethanol, ethanol results in a less harsh, sweeter, easier to control effect. Except in the high treble, I mostly don't need to use it on the crown, except the top half octave. On a well designed treble and good bridge and hammer pinning, hammer shaping, and hammer strike point location, even in the high treble, up to 88, the tone can be excellent with B-72 only at near crown. Most of the rest of the scale, even with the Bacon felt I use exclusively these days and for the last few years, very little 10-to-11/1-to-2 is needed in select parts of the scale.
The amount of doping varies according to the belly etc and the quality of Bacon felt Bacon supplies Ray Negron with. The Bacon felt manufacturing can be somewhat uneven batch to batch, so the requirements, set-to-set, vary according to the felt quality.
I never use the supply house plastic.
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Jim Ialeggio
grandpianosolutions.com
Shirley, MA
978 425-9026
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Original Message:
Sent: 12-28-2019 13:00
From: Susan Kline
Subject: keytop solution
Condolences.
And I can tell you from personal experience that letting CA touch a formica countertop is a bad and irreversible idea.
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Susan Kline
Philomath, Oregon
Original Message:
Sent: 12-28-2019 12:36
From: David Pinnegar
Subject: keytop solution
I was intending to start a thread on an allied subject as some might have experience of ivory keytops and acetone.
At Christmas I got into trouble from my wife as I'd mended a canteen of cutlery case with CA . . . . and unfortunately some of the bone or ivory handles stuck to the cloth with some glue that had seeped from goodness knows where. I tried using acetone to dissolve the CA sticking the cloth to the handles, and unfortunately the acetone started to attack the bone or ivory too. So I've probably got no solution (forgive the pun) other than mechanical removal, finest sandpaper and shellac polish. But anyone with experience of such things might possibly have some helpful knowledge to share . . .
Best wishes
David P
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David Pinnegar, B.Sc., A.R.C.S.
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+44 1342 850594
Original Message------
Eric,
I'm no chemist, but I believe you're trying to dissolve the wrong plastic in acetone. I'll make a guess your making a hammer hardening solution; a solution I've used for years with excellent results when applied in the correct location. The plastic that dissolves in acetone is pyralin sold by Schaff Piano Supply with part numbers beginning with 1380. I cut pieces into quarter inch squares and let is set overnight in the acetone. As for the proportion of acetone/pyralin for hammer hardening, I will leave up to you for experimentation.
Roger