Dampp Chaser and Grand Action

[Richard Strang]

I am not a rebuilder, but I have repinned an entire action and I have
repinned an entire pinblock. Both are big jobs, but I think the pinblock job
was easier.  A grand piano that needs a DC on the action to keep it playable
is going to need either an action repinning job if the heater is removed, or
the next sized tuning pins in 10 years. The customer should take his pick.
Even a low wattage heater is going to dry out the pin block and loosen the
pins, so which job do you want to do?

Richard

-----Original Message-----
From: pianotech-bounces@ptg.org [mailto:pianotech-bounces@ptg.org]On
Behalf Of David Love
Sent: Tuesday, August 26, 2003 7:06 PM
To: JIMRPT@aol.com; pianotech@ptg.org
Subject: Re: Dampp Chaser and Grand Action


I don't know what's so complicated about this.  If you treat the centers
when the humidity is high, then when the humidity drops they will be too
loose, if you treat the centers when the humidity is low, then when the
humidity is high they will be too tight.  If you address the centers when
the humidity is medium, then when the humidity is high they will be tight
and when it is low, they will be too loose.  This is know as the Goldilocks
theory in physics.  IMO it would be better to treat the humidity so that
anything done to the centers will not be subjected to further swings in
humidity.  The question being posed, is whether or not that can be done in
such a manner as to not harm the block.

David Love
davidlovepianos@earthlink.net


> [Original Message]
> From: <JIMRPT@aol.com>
> To: <davidlovepianos@earthlink.net>; <pianotech@ptg.org>
> Date: 8/26/2003 2:45:09 PM
> Subject: Re: Dampp Chaser and Grand Action
>
>
> In a message dated 26/08/03 1:40:25 PM, davidlovepianos@earthlink.net
writes:
>
> << If sluggishness were the only problem then it could be treated, but
since
> the problems come from changes in humidity, then treating sluggishness is
> only as good a fix as the humidity is constant. >>
>
> I am lost here...care to expand a little?
>
>
>  <<What I am trying to treat
> is changes in friction that come with humidity swings.  Addressing the
> action centers won't accomplish that. >>
>
>  Gonna defy the laws of physics? :-)
> Addressing the action centers is the best way to address "changes in
> friction" as this is where most of the friction changes happen during
humidity swings.
> There are other, lesser, causes of friction change but the centers are
the
> most amenable to correction.
>
>
> <<" The humidity needs to be regulated
> in some manner. >>
>  Or as an alternative the piano needs to be made to work across the full
> spectrum of humidity swings.
>
> << Convection problems could be treated by closing the lid of
> the piano when not in use.>>
>  Not really. A string cover would help more.
>
> <<  Speculating on the potential problems is easy,>>
>
> Well I make a pretty good living by replacing pinblocks and restringing
> pianos where a piano tuner installed a DC to "solve sluggishness
problems" and that
> ain't speculation.
>
> << I would guess that the low
> conductivity of wood would render a low wattage heater bar relatively safe
> if located below the level of the flanges on the action bracket. >>
>  OK........ go for it! :-)
>
>  Terry's thought about putting a DC under the keybed and placed under the
> action has some merit. At least the convection would happen in the
correct area.
> Jim Bryant (FL)



_______________________________________________
pianotech list info: https://www.moypiano.com/resources/#archives