Thanks for sharing your protocol, Mark. Sounds promising. Think I'll try it out on the set of keys currently in the shop for rebushing.
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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Original Message:
Sent: 05-20-2023 06:04
From: Mark Dierauf
Subject: dampp-chaser liquid treatment for balance key hole ?
I've had very good luck glue sizing over the years, including some that I would have thought lost causes, with noticeable side-to-side play as well as back and forth.
Using a balance hole sized brush, I start by painting with boiling water to swell the holes then immediately follow up with very thin glue while the wood is still warm. I've used both titebond and hide glue with the same results. After drying a day or two I fit the keys individually with the tapered burnishing tool leaving them just a tad tight. Lastly I paint the inside of the holes with McLube and lightly burnish in a little teflon powder. This, plus more McLube on the pins gets me the fit I want while still leaving the hole as snug as possible. All this represents a fair amount of labor, so I usually do it as part of key bushing (and sometimes key pin) replacement jobs.
Original Message:
Sent: 5/19/2023 11:18:00 AM
From: Bruce SATO
Subject: dampp-chaser liquid treatment for balance key hole ?
Hello everyone,
I'm used to use the glue-sizing method (cardinal points needling inside the hole and water-wood-glue mix 70/30) but it doesn't work everytime (wood swells then retracts overnight). So I was searching for an alternative to the more invasive fixes. I read somewhere recently the dampp-chaser liquid treatment can be used to swell the wood around the balance key hole and I've just tried it. I would say it seems to work but is it better than to glue-size the wood ? Maybe... As a matter of fact, It seems that the dampp-chaser liquid applied at the room temperature (a thin paint brush of the liquid inside the bal. rail hole) makes the wood swell enough to a better pin fit and the correct friction is preserved (the key falls in a smooth but easy way during test). Perhaps the liquid pad treatment can be more efficient at hot temperatures. I just got to make tests about it.
What's your best way to fix a moderate reamed key hole ? I often see pianos with no ''pulley'' key here but when I do the test (lift up the key back 1 – 2mm and release) often I have many keys that fall too easily with no friction at all and I can hear (but not see) a very tiny knock when I push-pull some keys.
Thank you,
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Bruce SATO
QC
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