[pianotech] Kawai Lyre affected by humidity swings

Barbara Richmond piano57 at comcast.net
Sun Feb 28 13:03:21 MST 2010


Ugh. 

OK, I was busy and didn't get right to the lyre--here's what happened. The RH at the school 
(where the pianos lives) is low--I'm not sure how low, because my hygrometer went on the fritz, 
but it must be below 20%, probably more like 15% (or worse). I brought the lyre home to my 
comfortable house--~30% main level and ~30-40% on the lower level--walk out basement. 
It didn't take long, the posts got tight again... 

I set up a card table with blankets draped over it, and inside I set a heater, the lyre & wedges-- 
plus my new data logger with LCD display (Al G. I got one, it's nice). It didn't take long for the 
wood to take on the moisture, how long should it take to dry it out? It's not as loose as it was, 
yet. If I don't dry it out, I figure it will just loosen up again. Then I was wondering if I manage to 
dry it out to the level it was, then put it back together with bigger wedges (or whatever), will any 
damage occur in the spring & summer when the humidity skyrockets? 

Could I reduce the swelling & shrinking by painting CA glue or coating everything with some 
sort of epoxy on the open surfaces to seal the wood? If I did this, perhaps I wouldn't have to dry 
out the wood so much? Should I use wedges made out of a particular type of wood for stability? 

Other suggestions? 

Thanks. 

Sigh. 

Barbara Richmond, RPT 
near Peoria, Illinois 

PS--- Al G., I decided on the Thermoworks LCD data logger, (TW-USB-2-LCD) 
http://www.thermoworks.com/products/humidity/index.html because when I was looking to 
replace the unreliable Mannix hygrometer that hasn't worked well for me and now doesn't 
work at all, there didn't seem to be many models out there that would measure really low RH. 
So what the heck, now I stop by my computer on the way out the door, plug in the data logger 
to turn it on and take it with me for the day. It was very helpful setting up the tent for drying out 
this lyre, since my heater doesn't have the type of thermostat that one can read and I can check 
the RH in the tent. The button on the data logger starts it up, so one doesn't have to program a 
time to start it (but you can if you want). 




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