humidity level for conditioning new pinblock

[Bob Hull]

Thanks for the feedback about the pinblock mc
conditioning prior to drilling.

With the dehumidifier running full tilt again (rain
here in TN for last several days) the shop humidity
level has come down.  The pinblock in the hot tent is
being basked in 38% rh.  Was 44% yesterday and 54% two
days ago.  I don't think the block was exposed to the
60+ rh for too long, so I don't think I'm too worried.
 I don't have the Hoadley handbook - is that the
Physical Laboratory Handbook?

I think my dehumidifier maybe too small for my shop
(1400 sq. ft.) since it runs constantly in the spring,
summer and fall.  I shoot for about 45% rh.  Does
anyone else's dehumidifier in a similar climate have
to work that hard?  

Bob Hull 


--- Farrell <mfarrel2@tampabay.rr.com> wrote:

> Well, I haven't seen a reply to your post yet, so
> I'll take a stab.
> 
> First of all, if you have a dehumidifier, why is
> your shop up to 63% RH -
> although that's not really terribly excessive? I
> would suppose the best
> humidity level would be whatever RH the piano is
> expected to live in - or
> rather, the middle of the RH range expected.
> 
> I guess if you live in New Mexico, it may be
> worthwhile to let the block sit
> for a month or so to let it come somewhere in the
> range of it's
> surroundings. If you live in coastal Washington
> State, you may want to wait
> a while also while the block absorbs some water. But
> for most climates, your
> shop is probably not so terribly far from some
> midpoint of an expected RH
> range for the piano's future.
> 
> But how long has is been in your shop? Did you just
> get it delivered from a
> supply house? If so, you may not really have much
> idea at all about the MC
> of the wood.
> 
> I like to buy my wood at least six months to a year
> before I intend on using
> it - most of it sits for more than a year or two
> before use. I've got a
> large supply of rough-sawn spruce, maple and a few
> pinblocks residing in my
> constant-humidity shop. Doing that simply eliminates
> this whole
> hard-to-answer question/concern regarding wood MC
> stability. A
> several-inch-thick hunk of hardwood can take months
> for its MC to come into
> equilibrium with its environment, depending on the
> RH/MC contrast.
> 
> Bottom line: It's probably OK. If you are not in a
> rush on this job, let it
> sit for a few weeks or however long you can. A good
> cross-grain-laminated
> pinblock shouldn't be changing all that much is size
> anyway with small
> changes in MC.
> 
> Or maybe I should have just kept it short and said:
> I dunno.     ;-)
> 
> Terry Farrell
> 
> www.farrellpiano.com
> 
> ----- Original Message ----- 
> From: "Bob Hull" <hullfam5@yahoo.com>
> To: <pianotech@ptg.org>
> Sent: Saturday, October 30, 2004 2:10 PM
> Subject: humidity level for conditioning new
> pinblock
> 
> 
> > The humidity in my shop today is 63% and higher
> than I
> > usually try to keep it.  I'm getting a block
> ready,
> > the flange fitting is done; What would be the best
> > level for the humidity to be and for how long to
> > enhance the drilling/pin torque outcome? This
> block
> > (Weber 5' 6") has been a "bear" for me with a
> double
> > flange, plus thicker in the bass, and bow or warp
> > across the block area of the plate.
> >
> > I just put the block under a "tent" with 2 heater
> bars
> > and it has dropped the humidity to 54% over the
> course
> > of . I don't have a MC gauge but I have a
> > dehumidifier.
> >
> > I'll appreciate your comments.
> >
> > Bob Hull
> >
> >
> >
> >
> >
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