On Sep 17, 2009, at 8:45 PM, Wimblees at aol.com wrote: > Ideally that needs to be the case. But unfortunately I have found > too many felt covers touching the strings. They were either put > there by another tuner, or by the customer, who put on his/her own > hand made cover, that is nothing more than a square piece of felt > bought at the fabric store. The same kind of argument can be made against full Dampp-Chaser systems. Install the tank too close to the board, especially without the baffle or with it badly placed, and it will cause water damage to the board. Or let it go dry, and it may help cause the soundboard crack it was intended to prevent. If a customer is willing to pay for a system, or for a custom string cover, some education and proper installation should go along with it. Bad results from bad installations are not a reason to recommend against. > > However, as Paul indicated, felt absorbs moisture. But this is where > I think he and I would disagree. I think the felt then releases the > moisture onto the strings. Wool does absorb moisture. If it is in contact with a solid surface, some of the moisture will be transferred directly, more than through air. If it is not in contact, the transfer will be very slow through the air, and will be less than if there were no baffle between moist air outside the system (above the cover) and the soundboard, because the cover will create a dead air space - no air movement. Coupled with a humidity control system installed below, it will help that system maintain a constant moisture content in the wood. > I have observed many grand with felt string covers where the strings > are still rusty. But then I have seen grands in homes right next to > the ocean, with a ranch hide string cover, two damp chaser rods > under the piano, and a full length piano cover over the piano, and > the strings still got rusty. > Wim I don't have that much experience with high humidity, except with pianos arriving from other climates. I have found, in limited cases I have seen, that a string cover can keep strings meticulously rust free, in a couple cases from very wet coastal areas. People who have day to day experience will know a lot more about how effective they are - but the key is to know the whole history of the piano: when was the cover installed? Before or after the strings and pins became rusty? I think that the salt air of real coastal situations is probably going to make it through and cause rust, though the cover(s) will no doubt help slow it down. My sister lives in Kaneohe, HI, and has to replace refrigerators after a few years because they rust out. She gave up having a piano because strings rusted out and broke so often. Regards, Fred Sturm University of New Mexico fssturm at unm.edu
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