more board question

[Gene Nelson]

see below
----- Original Message ----- 
From: "Farrell" <mfarrel2 at tampabay.rr.com>
To: "Pianotech List" <pianotech at ptg.org>
Sent: Saturday, July 21, 2007 1:32 AM
Subject: Re: more board question


> Hi Gene,
>
> I keep my shop right between 45% and 50% RH. My soundboards have 
> equilibrated with shop conditions when I set my bearing. I see no reason 
> to dry things down to glue-up MC.
I call it my shop - my wife calls it her garage. MC is more in the range of 
30% to 65%.
>
>
> Setting bearing on rib crowned soundboard assemblies will be less affected 
> by small changes in RH/MC. I would presume stable, repeatable environment 
> RH would be rather critical in setting downbearing on a compression 
> crowned soundboard system. I presume you are working with a rib crowned 
> soundboard here - my guess from your relatively high MC at rib/panel 
> glue-up. If yours is rib crowned, who designed it?
You are correct - Dale Fox tutored me on previous projects but this board is 
my design.
>
> Where are you doing this work? In your shop? What kind of climate control 
> systems do you have? What kind of RH monitoring system do you have? What 
> range of RH does your shop experience?
Climate control is nothing but a humidifier (swamp box) to keep things from 
drying out too much.
Monitoring is the cheep hygrometer that also goes with me to clients homes.
30% to 65% rh range
>
> I have simply never observed bearing conditions in the new board change 
> over time because I keep my shop environmental conditions very stable. I 
> find that helps keep things predictable and keeps me from pulling my hair 
> out. I find my shop RH range to be ideal, because I install Damp-Chaser 
> systems on all pianos that I put soundboards in, and thus, presumably 
> soundboard MC will stay close to my shop conditions - that way, wherever I 
> set bearing, bearing should remain constant.
Very helpful - I probably will not be able to control rh in a 5% range in 
the forseable future but it is a goal.
Thanks
Gene
>
> Hope this helps.
>
> Terry Farrell
>
> ----- Original Message ----- 
>> Getting ready to set bearing tomorrow and am very curious how many people
>> try to get the board/rib/bridge assembly close to or at the % moisture
>> content that was in the board when the ribs were glued on as a 
>> preparatory
>> step.
>> When taking the bearing measurements that will determine how high the
>> bridge will be, it would appear to be important to do this?
>> The reason I ask is that I have observed the available bearing in the new
>> board change over time depending on the relative humidity.
>> The mc was about 6.5% when ribs were glued on.
>> Any thoughts would be appreciated.
>> Gene Nelson
>
>
>
>