Drying pinblock before stringing

[Ken Jankura]

> Huh? It is my understanding that, for compression set
> to occur, it must have something to compress AGAINST.
> Hence, a pinblock with NO PINS IN IT, when dried, will
> NOT develop compression set in the wood fibers around
> the freshly drilled holes.

But a pinblock dried down with no pins in it does not do the piano much
good, now does it? Take the situation to the extreme to more easily
visualize. Dry the pinblock down to 0% in an oven, take it out, drill, and
pin. Place in real room of 50% RH. Those pins are gonna get mighty tight in
a day or a week or a month, however long it takes to absorb to EMC. The
compression set will start immediately, and be unnaturally severe. I agree
with RicB that your 32% RH is probably just perfect to shoot for EMC in a
block before drilling, etc. So, go and do good work, you have our blessing
:-)


>Furthermore, while I will
> concede that a hole drilled in a block of homogeneous
> wood MIGHT get bigger as the block is soaked (probably
> depends upon species and cut, to some degree)

It WILL get bigger, regardless of species. It will become oblong and of
increased area, which by my definition means bigger. Holes drilled into
endgrain may remain almost unchanged in size, though.
Ken J

>I also
> acceept Ken Jankura's statement that a constrained
> piece such as a glued up and laminated pinblock will
> NOT expand outward exclusively, and some force of
> expansion will therefore be directed INWARD towards
> the pin holes, making them smaller.
>      Which is EXACTLY why compression set opccurs in
> pinblocks over time! Sheesh! I had some trouble
> learning to shave in a mirror when I was 14, but this
> is EASY to conceptualize! Doncha think?
>     Lovingly,
>     Thump
>
> P.S. It does not always take years. Around here, where
> the humidity fluctuates wildy, it may take much less.
>
>
> --- Ken Jankura <kenrpt@earthlink.net> wrote:
> > Which is probably why it usually takes years to be
> > further damaged enough by
> > EMC changes and pin forces to be noticed?
> >
> > ----- Original Message -----
> > From: "Ron Nossaman" <RNossaman@cox.net>
> > To: "Pianotech" <pianotech@ptg.org>
> > Sent: Friday, February 28, 2003 10:01 AM
> > Subject: Re: Drying pinblock before stringing
> >
> >
> > >
> > > >  Drying the block down too much would not be
> > good as it may
> > > >start the process of compression set around the
> > pin faster than it will
> > > >occur normally.
> > >
> > > Hi Ken,
> > > Just installing a pin in any block compresses the
> > wood far beyond it's
> > > fiber stress proportional limit. In other words,
> > the hole won't spring
> > back
> > > to it's original diameter if the pin is removed
> > immediately after driving.
> > >
> > > Ron N
> > >
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