Damp Chaser in old upright

[Farrell]

What's with all this "fuzzy math"? I thought only American Presidents knew
how to use that? A piano is made of wood (admittedly with a small percentage
of water) and metal, and felt and glue, etc. It isn't made of water. So how
do you come to your conclusion based on a 400 lb. weight of a typical piano?

I have measured temperatures inside a studio piano up to about 95 F (35 C),
when equipped with a 50 W rod and a standard calibration humidistat. The
temperature that the piano achieves will be dependant on two things: 1) the
maximum rod temperature - let's just assume it gets way hotter than we want
any piano, and 2) the rate at which heat energy escapes the interior of the
piano - either through direct transfer of air between the piano interior and
the room atmosphere (I would guess this is the primary route) and/or thermal
transmission through the case/soundboard/etc. It will not depend much on the
weight of the piano. The weight (wood weight, that is) will only affect the
total time required for the piano to come into equilibrium with the DC
system and room atmospheric conditions, when you have a properly sized DC
system. The weight of the piano could however affect the ultimate
temperature only in the case where you have an improperly sized DC system.

I think.  :-)

Terry Farrell

----- Original Message -----
From: "Don" <drose@dlcwest.com>
To: <pianotech@ptg.org>
Sent: Sunday, July 08, 2001 11:16 PM
Subject: Re: Damp Chaser in old upright


> Hi Tony,
>
> A little point 50 watts is about 180 btu's. A British Thermal Unit is
> defined as the energy it takes to raise one pound of water one degree f.
> Assuming an upright piano weighs 400 lbs 180 btu's is *never* going to get
> the piano to 50 degrees C. (unless the room is 48 C already *grin*)
>
> Use the 50 watt rod with a humidistat. Things will be just fine.
>
> Regards,
> Don Rose, B.Mus., A.M.U.S., A.MUS., R.M.T., R.P.T.
>
> Tuner for the Saskatchewan Centre of the Arts
>
> mailto:drose@dlcwest.com
> http://donrose.xoasis.com/
>
> 3004 Grant Rd.
> REGINA, SK
> S4S 5G7
> 306-352-3620 or 1-888-29t-uner