Dampp Chaser and Grand Action

[Don]

Hi David,

Do try a bottom cover and caution the owner to keep the "hood" (as one of
my clients calls it) fully shut. If that doesn't help enough then consider
a rod of 8 watts below the key bed. Increase that as necessary up to 50
watts before moving an 8 watt with a separate humidistat (high setting {50%
not 42%}) to the action cavity. 

At 10:39 AM 8/26/2003 -0700, you wrote:
>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)
>>
>>
>>
>>
>> _______________________________________________
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>
>
>
>_______________________________________________
>pianotech list info: https://www.moypiano.com/resources/#archives
>
>

Regards,
Don Rose, B.Mus., A.M.U.S., A.MUS., R.P.T.

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