As some may already know, CA viscosities can be mixed to achieve a "custom" viscosity. I do this routinely when I need something a little more substantive than the water thin, or a little less than the medium (or whatever).
The only rule is that you must remain in the same "family" of chemicals. There are at least two families of CA. If you cross over the family line it will cure almost instantly. Probably not what you want.
I have also found the flexible formula to be more to my liking in most wood work (although NOT for bridge pins). In the pinblock it gives a more normal feel in tuning.
Original Message:
Sent: 11-19-2017 06:52
From: Tim Coates
Subject: CA on bridge pins…a follow-up…ughh
So, perhaps there is an argument for NOT using thin CA on bridge pins. I've had success using one drop of medium CA on the back side of bridge pins. It seems to be drawn in around the pin, but doesn't travel easily to the string, etc. It is labeled "gap filling".
Also, I've commented before about the video the PTG has posted demonstrating CA application to bridge pins. It is an over the top application and in my estimation WAAAY TOO MUCH CA.
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Tim Coates
Sioux Falls SD
Original Message:
Sent: 11-18-2017 21:43
From: Jim Ialeggio
Subject: CA on bridge pins…a follow-up…ughh
Grand - August Foerester 170, 1996 manufacture. Regularly serviced by me, tunings twice a year, 2 day regulation a couple of years ago, original hammers, heavily played, hammers to be replaced next time shaping is required, if not before, Renner hammers - dense.
Excellent condition all around except for the bridge which was constructed very poorly. Solid european hardwood bridge root, no cap in the agrafffes sections, flat sawn, scarf jointed, scarfed in the capo area. Capo area of bridge capped in a very odd fashion that I still can't quite figure out. As I mentioned in the OP 1.5" pieces of some quarted stock, the 1'5" pieces edge glued perpendicular to the center line of the bridge. These cap glue joints are opening, but not cracking away from the root, just opening.
Condition of cap and pins – actually looks okay. No obvious visual distortions of the holes in the tenor, and very slight widening of the holes in the capo. Only one pin at the capo strut with a visually widened hole. However, despite reasonable visual condition, every string from C4-C8 was false and responded to the screwdriver test.
Tenor agraffe area slow moaning beats in the attack made for a noisy attack, with an indistinct pitch. Capo, classic fast shimmering beats.
Board still good with sustain, but is showing signs of a lowering of impedance. The lower impedance of the board is asking for a softer hammer at this point, as given the filed hard Renner hammers, it is a bit too easy to drive the notes to break up earlier than one would like, despite voicing.
No dag on the cap, as is common on European pianos.
CA, dryburgh red (water viscosity), fresh…just bought it from dryburgh this past week.
Application, strings on, up to tension. Pipette application. Since the pin holes, as I said, were not seriously elongated, at least visually, application of CA went under the strings on the cap and into the hole at about an equal rate, adhering the strings to the bridge cap. This as opposed to more elongated holes in really beat caps, which allow the CA to be drawn first and exclusively into the holes. Because of this pin/string equal capillary action the strings adhered to the flat of the bridge cap, and built up some CA at the pin termination, mostly on the right string. There was a small CA build up at the pins in general.
Application rate may have been a bit generous, but on the other hand, I did have to repeat apply a fair number of pins to kill the beats. All CA applied in the same 1.5hr initial session. Left it overnight and came back the next day to work on it.
When I came back the next day, there were some isolated string termination noises. I cleaned the obvious termination noises with a dental pick, and tuned. Came back the next day, to see the fresh tuning was history. The adhered strings on the cap flat let go helter skelter. When I heard the failed tuning is when I let the tension down and got further into it.
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Jim Ialeggio
grandpianosolutions.com
Shirley, MA
978 425-9026
Original Message:
Sent: 11-18-2017 16:40
From: Ed Sutton
Subject: CA on bridge pins…a follow-up…ughh
Jim and Fred-
It might help to get comparative details from you both.
What brand and conditions of pianos?
Vertical or grand?
What kind of coating on the bridge tops?
Brand of CA and method of application?
Thanks!
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Ed Sutton
ed440@me.com
(980) 254-7413
Original Message:
Sent: 11-18-2017 16:10
From: Jim Ialeggio
Subject: CA on bridge pins…a follow-up…ughh
Fred,
Have you done full compass CA jobs, or single/several note applications, or both?
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Jim Ialeggio
grandpianosolutions.com
Shirley, MA
978 425-9026
Original Message:
Sent: 11-18-2017 15:42
From: Fred Sturm
Subject: CA on bridge pins…a follow-up…ughh
It is always interesting to read other experiences that are sharply at odds with one's own. FWIW, I have CA'd bridge pins with strings in place many, many times. Have not yet experienced any tone dulling phenomenon.
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Fred Sturm
University of New Mexico
fssturm@unm.edu
http://fredsturm.net
http://www.artoftuning.com
"We either make ourselves happy or miserable. The amount of work is the same." - Carlos Casteneda
Original Message:
Sent: 11-17-2017 00:41
From: Chris Chernobieff
Subject: CA on bridge pins…a follow-up…ughh
What I got out of this tragedy avoided story, is the bad idea of experimenting on a customer's piano. IMHO, before offering a procedure as part as one's services, it should be worked out (along with any potential problems) in advance. On the second part (again easy to prove in the shop)- the idea of epoxy wicking onto the speaking length and having a dulling effect. Seems as obvious as a mouse attracted to peanut butter on a spinning bottle trap to me.
But that's another story.
-chris
#caveman
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I have a piano in my Nuclear Fallout Shelter, and my competitors don't. How silly is that?
chernobieffpiano.com
865-986-7720
Original Message:
Sent: 11-14-2017 22:10
From: Jim Ialeggio
Subject: CA on bridge pins…a follow-up…ughh
So I decided to CA an on-site cap.
The patient: August Forester 15yr old 190cm grand. Nice piano. I've been working on this piano for about 6 years. Excellent customer, regular full service appointments. Customer serious classical chops. Customer has serious ears, and performs. All the piano's systems in excellent condition, with the exception of the bridge.
Bridge is not up to the rest of the instrument…long bridge from D5 (or so) down is solid flat sawn European something like maple-ish, no cap. Scarf jointed in the fifth octave, where it incorporates a very weird cap, glued up edge to edge pieces 1.5" wide perpendicular to the center line of the bridge. All these edge glued pieces have very fine hairline cracks forming. Its not falling apart, and pins are not visually looking compromised, but boy what a racket.
False beats from #36-88. Tenor notes, the entire flat sawn part, where I don't usually hear false beating, exhibited a slow moan…each string having a slightly different speed, slow moan in the attack. Screwdriver test proved the pins as culprit. Doesn't look bad, but the moan was there and defining the tone of the instrument in that area as quite nasty in the attack. Hard to tune. This section was tonally suffering from the untuneable attacks, and is the section that drove my decision to do this treatment.
False beats on every string in the treble. Faster classic treble beating giving the treble a shimmering poorly defined pitch – Responded to the screwdriver test also. I could have lived with this section, as I could tune it, and it has a shimmery, though slightly harsh tone. But the tenor needed fixing.
Since I don't usually do triage CA work, I read up on various CA treatment protocols; Ron's article, numerous posts to lists. Decided on the strings in place, at tension, water thin CA approach. All noted the quick nature of the "fix"…Priced it as such.
There have been some reports of "tone dulling" in this treatment. Responses mostly finger Ca creeping onto the speaking parts of the termination. I did ask, during one of these threads whether the apparently "dulled tone" was caused by the false-ness going away, but never got any traction on that idea. Still suspected this was a serious potential problem, ie completely changing the tonal profile of the piano, by significantly changing the attack.
Though somewhat hesitant to try the treatment, especially given a client with serious ears and a hard to tune and stabilize piano, I did the treatment. Piano lost its voice big time, dull, lifeless, short sustain…customers very worried…I knew how to get it back, as I realized, after this happened, that the hammers and all the tone regulating prior to this had been based on the attack profile defined by the falseness.
I knew how to fix it, but had not factored that amount of time it would take to let down tension, remove and clean strings from the pins, clean cap, bring up pitch, lift coils, chip 3 times, fine tune twice, shape hammers, re-voice, and assure my client that is everything would be fine, into my bid.
The piano is sounding quite nice now. The falseness is completely gone, but it is definitely a different piano. This different-ness may or may not drive my customer nuts…we shall see.
If I ever do this again ("if" factors highly here), it will be a $2500 job, to get the falseness corrected, voiced and tuning stabilized. It ain't no quick fix, as a compass wide application, at least in my experience. If this is undertaken on a decent piano, serious tone regulating chops will be required.
Glue did stabilize the pins nicely, as advertised. However, applied at tension, glue crept under the strings on top of the bridge cap. CA under the strings, adheres the strings to cap, such that after it is tuned in this condition, the string/cap bond will let go, with the tuning failing over-night. Also CA at the termination had to be scraped away, as there were weird string noises from the imprecise terminations.
Removing the strings from the pins and cap is the only way I would ever do this again.
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Jim Ialeggio
grandpianosolutions.com
Shirley, MA
978 425-9026
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