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. > 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
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