Dampp Chaser and Grand Action

[David Love]

This sounds like the most reasonable suggestion which I will try.  The
piano is a new NY S&S B.  The piano, when moved from the showroom (air
conditioned) to its new residence (high humidity at present, but showing a
wide range of fluctuation on the hygrometer over the past year), became
quite stiff.  Sample measurements of up and down weight show friction
readings ranging as high as 20 grams on some notes.  Most of the problems
on the measured notes seem to be in the hammer flanges.  Jacks are also
sticking and a precise adjustment of the repetition spring is impossible
with these types of humidity swings.  At present, as you can imagine, the
piano also has repetition problems.  While treating all the flanges is an
option and may be necesssary, if only to provide even resistance, I prefer
to try and stabilize the humidity and create some kind of baseline before
doing that.   While I understand the downside potential of putting a heater
bar in the action cavity, it seems that the problems reported have occurred
mostly with high wattage bars without humidistat control.  If we set too
much downbearing and the piano sounded like crap, you wouldn't choose to
avoid using any downbearing in the future.  Many of the things we do
operate on the edge of disaster if not regulated properly.  That doesn't
mean we shouldn't do them.  It's unfortunate that there isn't more research
on regulating humidity within the action cavity itself.  Perhaps the
manufacturer will see fit to conduct that kind of research.  It's beyond me
to do it at the present time.  However, it's certainly an important area to
control.  Since this seems to be an area of uncertaintly, I will opt for
the under-the-keybed position and hope for the best.  

BTW for you touchweight enthusiasts, FWs = 85% max on average with BWs
between 45 and 50 grams.  Add a little high friction and DWs were near 70
grams on some notes.  Nice....  

David Love
davidlovepianos@earthlink.net


> [Original Message]
> From: Tony Caught <caute@bigpond.com.au>
> To: Pianotech <pianotech@ptg.org>
> Date: 8/27/2003 11:32:09 PM
> Subject: Re: Dampp Chaser and Grand Action
>
> Thank you Robin,
>
> I was about to suggest the same about fitting a rod under the keyboard, I
> have done the same in Darwin Australia and have never had further problems
> with sticky actions.
>
> Some one once said that you don't fit Dampp-Chasers to fix sticky actions,
> only to keep the pitch constant but believe me, the customers just want to
> play their pianos knowing that the piano is out of tune a little (or a
lot)
> is natural in this humid weather.
>
> It Works
>
> Tony Caught
> Adelaide Australia
> caute@bigpond.com.au
>
> ----- Original Message -----
> From: <DCrpt@comcast.net>
> To: <davidlovepianos@earthlink.net>; "Pianotech" <pianotech@ptg.org>
> Sent: Wednesday, August 27, 2003 10:04 AM
> Subject: Re: Dampp Chaser and Grand Action
>
>
> >       I was trained in Dampp Chaser installation by Wendall Eaton.(Well
> known
> > consultant and Dampp Chaser distributer back in the 80's).He taught me
to
> cure
> > sluggish keys and action centers in a grand by mounting a 7-F (15
watt)on
> the
> > underside of the keybed just in front of the top of the pedal lyre and
of
> > course connected to a humidistat.I have done this on many
> installations(most
> > all with complete systems)and have not seen any problems in over twenty
> > years.The principle of heat rising through the key bed helps keep the
keys
> and
> > action dry with out heating the pinblock.I have found it also stabilizes
> > Stienway key frames so the glides stay regulated.
> >        I will add that it is an absolute no no to put a rod of any
wattage
> > inside the action cavity.                          Robin Olson  RPT 
Wash
> DC
> >         P.S. for some reason my e-mail server does not include my return
> > adress on replies to the ptg list.Sorry if that bothers any of you.
>
>
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