Dampp-Chaser threads

[Susan Kline]

At 11:28 AM 3/9/98 -0600, Don wrote:
>Hi Greg and Mary et al,
>
>One very useful comment was made about 2 years ago on the listserv.
>Cigarette smoke travels in a room at 44 feet per second. I see *no* reason
>why water vapour should *not* do likewise.

Hi, Don!

At the risk of sounding pretentious, this seems a _very good_ time to 
point out that just because something shows up on a list, it doesn't 
mean you should chuck your common sense into the closet and lock it away.

Picture: You are in a large room, such as a concert hall, 44 feet long.
Someone lights a cigarette on stage (heaven forbid) and you are sitting
in the back row. _One second_ later you smell it ... he hasn't even 
blown the match out yet, you can see the initial puff of smoke as he exhales,
about 1.5 feet across (if you have binoculars), yet you can smell it?

(and I know a bridge you may be interested in buying.)

_Picture_ the smoke curling off a cigarette ... it goes mostly upwards,
in slow and lazy curls, visibly still in strands, not instantly dispersed
to every corner of the room.

Of course, this doesn't mean that the humidifying aspect of a Dampp-Chaser 
doesn't spread water vapor through the house. The part that I tested was
the dehumidifier. I have no experience with the tanks of water. Purely as
a thought experiment, I could picture the water vapor, quite warm, coming
off the pad, and travelling upwards to the soundboard, displacing cooler
drier air, which would escape from around the bottom of the sides (by
convection). The board would absorb some water (some vapor would condense
since the board was cooler), a little would go through the holes for
nosebolts, (and possibly try to rust the strings!?) most would nestle there
under the board until it cooled, then it would fall and disperse through the
room.

The question that we seemed to be talking about was whether the Dampp-Chaser
system in a grand would affect the action, lurking behind the belly rail and 
above the keybed. I believe that if we were talking about the heat
of the dehumidifiers, in the soundboard area, it probably would hardly
affect the action at all. Wood is a pretty good insulator.

If we were talking about water vapor, I think it would concentrate under the
board, and then cool and disperse fairly evenly through the room, which we
assume would breathe at least a little. (Even a tightly weatherized house
breathes once or twice an hour, doesn't it? Or does it? In the mild
Northwest our houses are probably a lot more leaky.) My feeling is that by
the time the water was evenly spread in the room, it would be at a small
enough concentration not to affect the action _much_ ... maybe a little. I
see no reason it would
affect the action more than it would affect everything else in the room. It has
a fairly long path to follow to get into the action cavity.

Open to correction ... (if you don't ask you don't learn.)

Susan





Susan Kline
P.O. Box 1651
Philomath, OR 97370
skline@proaxis.com

"I don't want to go hunting for knowledge: I want it to come and grab me."
			-- Ashleigh Brilliant