[pianotech] treating bridges with CA

[Jim Busby]

Hi Barbara,

I have, with very good results. It did indeed do all three things you listed below. I even did it on our concert instruments and the false beats immediately disappeared on several problem notes. Never came back. I've done it on dozens of pianos.

But... with a couple practice room pianos the glue got under the string (blame it on old eyes) and made a few strings buzz like nothing I'd ever heard. I had to scrape the stuff out from there. Lesson learned? Don't be sloppy. And, more isn't necessarily better. 

Regards,
Jim

-----Original Message-----
From: pianotech-bounces at ptg.org [mailto:pianotech-bounces at ptg.org] On Behalf Of Barbara Richmond
Sent: Monday, November 30, 2009 4:57 PM
To: pianotech
Subject: [pianotech] treating bridges with CA

Greetings list, 

When I serviced a church's Yamaha C-6 (beyond warranty) for the first time a few years ago, the lower treble section was wildly out of tune. I tuned like crazy and was satisfied with how I left the piano. About six or seven weeks later, I happened to get called to tune the same piano for a music competition. I thought, "Ha, this is going to be a piece of cake." Ahem. Though the same section wasn't as badly out of tune this time, I was disappointed with what I found. Yes, there had been a change in season (late fall to no-doubt-about-it winter), but still, the out-of-tuneness wasn't the usual seasonal pattern. I had a look at the bridge; there were cracks--not huge (yet). The church wasn't a regular account of mine, but I mentioned to the person in charge that there was a problem that could get worse. She was interested in my opinion and asked me to make an estimate. I recommended CAing the bridge and installing a DC system. It's sort of a long story (I won't go into it), but eventually the person in charge started calling me to do the work there and I was asked to do something about the bridge. Unfortunately, they opted out of the DC system. 

So, I arrived to CA the bridge. Even with the right applicator, CAing can be tricky. I was very careful, but still, it's tight quarters working around strings & bridge pins, and it's a challenge to keep CA glue from contacting the strings. When a couple or more drops didn't go where they were intended, I decided if I was going to sin, I'd sin boldly (thank you Martin Luther). I thought about some key buttons that went through big seasonal changes that I had treated with CA when I rebushed them. What an improvement it made in reducing the swelling and shrinking (thank you, Dan Tassin.) I also thought about Ed Foote telling about treating the wood part of old Teflon parts with epoxy and what a difference it made in reducing the clicks caused by seasonal changes. So, I decided to be bold and apply the CA ever so slightly below the top surface of the bridge and have it wick in and up to the bridge pin holes. Then I applied enough CA so the remainder of the notching was all the same color. I was looking forward to the next time I tuned the piano to see if my efforts would improve the tuning stability in the section, but then there was one of those political bru-ha-has at the church (one of the musicians didn't know I was the person who had been working on the pianos, found out, and was angry that he hadn't been consulted)--so I won't be back there on a regular basis. Well, these things happen, but I'm mostly disappointed that I can't track the results of my bet--work--experiment--whatever you want to call it. 

Fast forward to today. I got called to come to another church and another 7 foot piano (this time an 18 year old Kawai) that is developing those little cracks in the treble bridge--not as bad as the Yamaha, but still a concern. Here's my opportunity to give it another try. My aim/goal the first time was to: 

1 Keep further damage from occurring. 
2 Help keep false beats at bay. 
3 See if the treatment helps tuning stability. 

Has anyone else CA'd a bridge this way and had the opportunity to see the results of your work?  Comments?

Thanks,

Barbara Richmond, RPT
near Peoria, Illinois