Different question about heater bars

[Richard Brekne]

Farrell wrote:

> > Moisture is not exactly "drawn out" of
> > the piano... rather the relative humidity is reduced.
>
> No and yes. Assuming that the air inside the piano is at some elevated
> reletive humidity and the soundboard is in equalibrium with those
> environmental conditions. Now turn on the Dampp-Chaser heat rod.The relative
> humididy in the interior of the piano is indeed reduced. That sets up a
> non-equilibrium condition between the reletive humidity in the piano
> interior and the moisture content of the soundboard wood. Because the air
> has less reletive humidity and can now hold more humidity, there will be a
> net movement of water from the soundboard to the air. So, it is reasonable
> to say that "moisture is drawn out of the piano and into the air.

Grin... How fun it is to watch language at work. I'll buy your interpretation of
the words "moisture is drawn out of the piano and into the air" in this
connection. Its actually what I was saying. Still, from the other standpoint..
absolute humidity remains the same within the wood as it does within the air..
expanding the air surrounding air, and thereby decreasing Relative humidity does
indeed create the non-equilibrium you describe, but as to whether or not one
describes the equalizing of this in terms of "drawing out humidity" or rather
that the soundboards air content also expands, retaining the same volume of
absolute humidity is ...grin.. up for discussion... I would choose the
latter.... for ..... clarity...hehe..

Keith.... sorry to be so picky...:)

>
>
> Terry Farrell
> Piano Tuning & Service
> Tampa, Florida
> mfarrel2@tampabay.rr.com

--
Richard Brekne
RPT, N.P.T.F.
Bergen, Norway