[CAUT] RH? Please enlighten me.

[Jim Busby]

Thanks Alan. This is most excellent.

Jim 

-----Original Message-----
From: caut-bounces at ptg.org [mailto:caut-bounces at ptg.org] On Behalf Of Alan McCoy
Sent: Wednesday, December 10, 2008 10:16 AM
To: College and University Technicians <caut at ptg.org>
Subject: Re: [CAUT] RH? Please enlighten me.

Here are an EMC table and excel EMC calculator attached. Maybe they'll get through the filters.

Alan


-- Alan McCoy, RPT
Eastern Washington University
amccoy at mail.ewu.edu
509-359-4627
509-999-9512


> From: Jim Busby <jim_busby at byu.edu>
> Reply-To: "College and University Technicians <caut at ptg.org>" 
> <caut at ptg.org>
> Date: Tue, 09 Dec 2008 17:14:32 -0700
> To: "College and University Technicians <caut at ptg.org>" <caut at ptg.org>
> Subject: Re: [CAUT] RH? Please enlighten me.
> 
> Thanks Don, all. Very enlightening.
> 
> Don, this paragraph from you helps me better understand the "why" of 
> cracked soundboards. We really have been lucky here at BYU to not have more problems.
> 
> Jim
> 
> From: caut-bounces at ptg.org [mailto:caut-bounces at ptg.org] On Behalf Of 
> Don Mannino
> Sent: Tuesday, December 09, 2008 12:41 PM
> To: caut at ptg.org
> Subject: Re: [CAUT] RH? Please enlighten me.
> 
> <<<My little quick rough guideline I try to give piano dealers and 
> schools for soundboard health is the following: if you hold a room at 
> 22ºc and 25%, the Spruce in the soundboard will be dried to about 5% 
> EMC (very roughly - it does vary by species and density).  So when the 
> humidity goes below 20% at comfortable room temperatures, then the 
> soundboard is being dried down farther than the factory did 
> originally, and the chance of cracks opening up is very high.  Some 
> soundboards can handle this better than others, but eventually they 
> will seek relief from the shrinkage and will need to crack.>>>
> 
> Don
>