help a beginner measure mc in wood with confidence

[Farrell]

----- Original Message ----- 
From: <jimialeggio5 at comcast.net>

> Regarding the accuracy over time...its easy enough to check down the road.
> Just put the gauge and a sample piece in the box or whatever, oven dry the
> sample and check against the gauge...no?

Yes you can. But then you are subject to all the hassles and questionable 
results of oven drying the Betty Crocker way.

> Terry, I have a question for you. I like the simplicity of your approach, 
> and
> will use it or a version of it on a keyboard blank I'll be making in a 
> couple
> months.

Be aware that if you are working with wood that is an inch or so thick, you 
can raise your drying times exponentially - it will take at least four times 
as long.....

But why would you be drying a keyboard blank down past room EMC (a room that 
has desirable RH that is - 40% to 50% or so).

> You have a great mc/width reference before ribbing, but don't you lose 
> your
> reference once the board is ribbed?

Yes.

> There are at least 2 times after ribbing
> when I'll
> want to know when that board is at or near the target mc; just before I 
> glue it
> in the case,
> and then again when I take downbearing measurements...it seems like you no
> longer
> have a reference dimension at these points.

That is correct. However, I don't need the reference after the panel is 
ribbed. I'm building rib crowned and supported soundboards. Even though I 
usually do put a ribbed soundboard in my hot box before gluing into the 
piano, it's more for protection against being broken than to dry down the 
board. The ribs pretty much lock in the panel dimension, so what difference 
does it make whether I dry the panel down to 6.5% MC prior to installation 
or just let it acclimate to my shop and come up to the 8 or 9% EMC? I keep 
my shop right between 40% and 50% RH - so I'm always working in consistent 
conditions for downbearing work - its all very contollable.

If you are building compression crowned soundboards, why would you want to 
dry the soundboard down to 5% or whatever your ribbing MC was for 
downbearing work - what does that do for you?

Terry Farrell