Personally, I don't actually like referring to CA as "glue". Yes, it says "glue" on the bottle, and is sold as a "glue", but in my mind I prefer to think of it as a liquid that turns to a solid...very quickly (and somewhat controllably). Yes, I know that all "glues" do this, but the speed and other aspects of the transformation seem to set it apart from others (perhaps in my mind only).
This allows me to expand my realm of uses for the stuff. (Remember that when it was first 'discovered' they didn't have a clue as to what to do with it so they shelved it).
Similarly, I do not think of, or refer to, EPOXY as "glue" (even though technically it is, or can be), because it's specific properties put it into a category somewhat different from what is typically called "glue". Those properties allow me to expand its usage beyond the realm of simply "glue".
Okay, so what's you're point, Grey?
In this particular type of instance, I would have no problem using CA in the wood portion of the pinblock, provided of course that the metal area can SAFELY be bypassed. The fact that the wood in the PB would be similarly threaded, this would actually be a very good platform for the CA to accumulate and reduce its diameter. Whether it soaked into the wood or not is somewhat irrelevant. The goal is to make the hole smaller so as to hold the TP reliably.
I would remove the pin, use either a Pro-tip or a pipette to go into the hole and saturate the wood underneath the plate. (Obviously protect the keybed from drips if the holes are drilled through). Chances are I would do it at least twice, testing the tightness in between. Each layer will build on the previous one by about .001"-.002" (effectively .002"-.004" on circumference).
I would consider this to be a conservative and viable repair option...not a band aid. The stuff is very durable.
My .02 only.
Pwg
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Peter Grey
Stratham NH
603-686-2395
pianodoctor57@gmail.com------------------------------
Original Message:
Sent: 07-16-2018 10:59
From: Ed Sutton
Subject: Re-enforcement of 19th.Century Wrest-pin Plank with CA Glue
Traditional pin dope contained glycerin, which attracted moisture from the air to swell the pinblock and increase torque. It also rusted the pins.
CA glue hardens and becomes plexiglas, almost instantly. After that it is completely inert.
My impression is that it does not penetrate deeply into the wood, but that it fills gaps and forms a collar around the pin.
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Ed Sutton
ed440@me.com
(980) 254-7413
Original Message:
Sent: 07-16-2018 10:26
From: Robert Anderson
Subject: Re-enforcement of 19th.Century Wrest-pin Plank with CA Glue
This is really a nomenclature comment, Steven. I was promoting the treatment of loose tuning pins to another technician and he asked me how long it would last. He said he had cut open pinblocks that had been "doped" and the "dope" had only penetrated something like 1/8". I don't think it is accurate to characterize CA glue as "dope" or "juice". CA glue IS glue, after all, and it glues wood cells together as well as filling voids. Pinblock restorers (and any other name they are called be) are, I think, mixtures of water, alcohol and rosin. They swell the wood and create some kind of added friction. I think it may be useful to make the distinction. Does that seem correct?
Bob Anderson
Tucson, AZ
Original Message------
In regard to using CA glue as a bandaid approach. I treated the pin block of an Steinway M 5 years ago; it was near impossible to tune and the owners were not yet ready to invest in a rebuild. 5 years and the piano is still quite tunable and holds well, the pins feel just as they did after I first did the treatment. If someone else tuned the piano I doubt they would sense that the block had been juiced.
While the piano should still be restrung, as long as it can be tuned, it is just fine from my customer's viewpoint. My point is that a CA treatment should be considered more than just a bandaid.
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Steven Rosenthal
Honolulu HI
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