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
>>
>>
>>
>>
>