Wood

[Delwin D Fandrich]

----- Original Message -----
From: "Don" <pianotuna@accesscomm.ca>
To: "Pianotech" <pianotech@ptg.org>
Sent: February 15, 2003 10:46 PM
Subject: Re: Wood


>
> Can someone suggest a better protocol for such an experiment?
>

Yes.

Put a piece of wood--since we're interested in piano tuning stability, let's
make it a Sitka spruce panel about 8 mm thick by, say 250 x 250 mm--in a
hermetically sealed environment stabilized at 70º F (or 90º F, or whatever,
just so the temperature remains stable throughout the experiment) and 50%
RH. With the wood sample placed on a very precise and accurate scale,
monitor its weight until it has stabilized. Rapidly raise the RH to 70% and
periodically monitor and record the weight change over time until the weight
of the sample has again stabilized. Rapidly take the RH back down to 50%,
again monitoring the weight change at the same time intervals. Following the
same procedure take the RH further down to 30% and then back up to 50%.

If you take weight readings frequently enough this should give you a pretty
good idea of the rate at which the sample absorbs and desorbs moisture. In
the end I expect you'll find it's about the same both ways.

Del