Dampp Chaser and Grand Action

[Farrell]

Someone (sorry, already deleted) mentioned the tendency  of the heat generated from the bar to flow up, over the pinblock, and out the gap between the pinblock and the belly rail. That's a good point. I think that it might be difficult to place a humidistat in the action cavity where it might be properly influenced buy the heat from the rod. I wonder if a humidistat in the action cavity connected to a rod placed under the keybed, below the action stack, might help? I would think it might keep the keybed warmed gently and then that heat can just gently rise around the stack - maybe the pinblock also, but the H2 should be controlling things so that it doesn't dry it down past 40% RH or so.

Terry Farrell
  
----- Original Message ----- 
From: "David Love" <davidlovepianos@earthlink.net>
To: "Pianotech" <pianotech@ptg.org>; <pianotech@ptg.org>
Sent: Tuesday, August 26, 2003 1:39 PM
Subject: Re: Dampp Chaser and Grand Action


> 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.  What I am trying to treat
> is changes in friction that come with humidity swings.  Addressing the
> action centers won't accomplish that.  The humidity needs to be regulated
> in some manner.  Short of regulating the entire house, I am looking for an
> alternative.  Convection problems could be treated by closing the lid of
> the piano when not in use.  Speculating on the potential problems is easy,
> but I'm wondering if there is any real data on methods of controlling the
> humidity inside the action cavity and effects on the pinblock.  Certainly a
> system of humidification of the soundboard area during a very low RH period
> doesn't help the pinblock.  And my guess is that a low wattage heater bar
> connected to a humidistat would not reduce the RH around the block to a
> lower level than 42%.  So, why, then, would a controlled dehumidification
> system hurt it?  Am I wrong in that a humidistat controlled action cavity
> is likely to reach levels which are too low?  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.  
> 
> David Love
> davidlovepianos@earthlink.net
> 
> 
> > [Original Message]
> > From: <JIMRPT@aol.com>
> > To: <pianotech@ptg.org>
> > Date: 8/26/2003 10:24:17 AM
> > Subject: Re: Dampp Chaser and Grand Action
> >
> >
> > In a message dated 26/08/03 11:35:54 AM, <mfarrel2@tampabay.rr.com>
> writes:
> >
> > << Why is a Dampp-Chaser rod "not compatible ...... period" in a grand
> >
> > action cavity? >> (T.F.)
> >
> >  For two reasons:
> > 1. Heat rises and the first thing it will run into in the action cavity
> is 
> > the pinblock.
> > Heat doing what it does, with or with a humidistat, will over time cause 
> > premature failure of the pinblock.....this ain't rocket science. :-)
> > 2. The DC installed in any area of the action cavity draws outside air
> into 
> > the cavity through convection as we would expect and verrrrry little of
> this 
> > 'warmed' air will actually get to the jacks/balanciers...this makes any
> benefit 
> > from a cavity installed DC problematical at best. Because of the openess
> of 
> > the cavity/block/platewebbing/capo area there is never any sustained
> drying of 
> > anything...well except for the block.......
> >
> >  No amount of "insulation" will stop the pinblock from drying out over
> time. 
> > The answer to this 'sluggishness' problem is to solve the real problem(s)
> and 
> > not treat the symptoms.........period.
> > My Opinion.
> >  Jim Bryant (FL)
> >
> >
> >
> >
> > _______________________________________________
> > pianotech list info: https://www.moypiano.com/resources/#archives
> 
> 
> 
> _______________________________________________
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