Pianotech

  • 1.  Acceleration of rust on strings in a heated church - is a quilted plastic cover to blame?

    Posted 04-05-2025 07:37

    A Yamaha C3 is in a small church and kept covered by a standard quilted cover.

    The church is well used and heated modestly, but doesn't have openable windows and the doors are always kept shut, so no ventilation. The priest swears that there is humidity control although I've never seen it.

    People coming in for services will be introducing humidity into the atmosphere and I don't see how it can escape. A candle burns continuously about 10ft away from the piano.

    15 years or so ago the strings were in perfect condition. Rust started appearing and seems to be accelerating. 

    If there is (invisible) humidity control, I'm wondering if the non-breathable cover is to blame. The instrument is opened for services and concerts, with people raising the humidity, and then closed and covered. I'm wondering about recommending that the instrument should be left with the lid down but open, and covered merely with a dust-sheet or other such cloth?

    Best wishes

    David P



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    David Pinnegar BSc ARCS
    Hammerwood Park, East Grinstead, Sussex, UK
    +44 1342 850594
    "High Definition" Tuning
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  • 2.  RE: Acceleration of rust on strings in a heated church - is a quilted plastic cover to blame?

    Registered Piano Technician
    Posted 04-05-2025 08:57
    I've always thought that a cotton felt string cover does more harm than good. The felt absorbs moisture and then releases to the strings. The quilt cover might be doing the same thing. 

    I would suggest you put a polyester string cover over the strings, instead of the piano cover. 

    Wim





  • 3.  RE: Acceleration of rust on strings in a heated church - is a quilted plastic cover to blame?

    Posted 04-05-2025 10:18
    Thanks

    It's not a string cover- it's a cover over the whole instrument

    I'm conscious that terminology might get confused between the two sides of the pond

    Best wishes

    David P

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    David Pinnegar, B.Sc., A.R.C.S.
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    +44 1342 850594



    Original Message


  • 4.  RE: Acceleration of rust on strings in a heated church - is a quilted plastic cover to blame?

    Registered Piano Technician
    Posted 04-05-2025 10:21

    The only material that should be used for a string cover is wool.  Pianos covered with a wool cover won't rust.  If you use anything else, the strings could rust.  Sometimes owners want to make their own cover, and they purchase an acrylic felt which is cheap and available in fabric stores.  This will trap moisture under it and the strings can rust.  In severe cases, I have seen Damppchasers under the cover (low watt).  Cotton will absorb moisture, but retains it and that will cause rust under a cover made with cotton.  That's why cotton isn't recommended for hiking gear for warmth.  Wool will absorb moisture, but then it will evaporate.  Of course it's much more expensive, but for this purpose it's ideal.  I have also sometimes used a dessicant, MusicSorb, under a cover to help absorb moisture.



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    Paul McCloud, RPT
    Accutone Piano Service
    www.AccutonePianoService.com
    pavadasa@gmail.com
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  • 5.  RE: Acceleration of rust on strings in a heated church - is a quilted plastic cover to blame?

    Registered Piano Technician
    Posted 04-05-2025 15:24

    David, I suggest buying a data logger that will provide information the variations (or not) in humidity and temperature. You can print out a graph of the variations which will make explaining things easier when discussing it with the priest, music director, et. al.

    And Paul McCloud's suggesting the proper usage of a wool string cover (in addition to the cotton quilted cover) is very good advice.



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    Patrick Draine RPT
    Billerica MA
    (978) 663-9690
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  • 6.  RE: Acceleration of rust on strings in a heated church - is a quilted plastic cover to blame?

    Posted 04-05-2025 16:35
    Thanks so much. Good idea and I'll find a cheap hygrometer to put inside so at least we'll know a measurement when we open it.

    Not being quite sure what we're talking about with respect to a "string cover" as English can be a different language across the pond.


    Best wishes

    David P


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    David Pinnegar, B.Sc., A.R.C.S.
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    +44 1342 850594



    Original Message


  • 7.  RE: Acceleration of rust on strings in a heated church - is a quilted plastic cover to blame?

    Registered Piano Technician
    Posted 04-05-2025 18:57

    To a certain extent, the bus has left the station in that once started it can't be reversed and will tend to accelerate over time. It also progressively degrades the tonal quality.

    I'm a little suspicious as to whether the piano cover is the sole culprit. Is there noticeable rust on other metal fixtures in the room such as window frames, hinges or electrical fixtures? How do the pedals and leg ferules look on the piano?

    There are electronic humidistats that will record over time for pretty low prices, you can put it inside the pianos and get read outs on a phone app and they record a month of data. Learning about the 24 hour cycle is helpful.

    Some people recommend a product called Bullfrog rust inhibitor. The type put in pianos comes in a 1/2"x12"x12" perforated cardboard box and emits a chemical that binds with metal to inhibit rust. The local piano dealer includes them with all his pianos. It was discovered here in the islands because the US Navy buys it in liquid spray form by the case. It can be found on amazon. People also use it in one form or another in shops, gun safes, etc. It won't solve your problem but might slow it down.



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    Steven Rosenthal RPT
    Honolulu HI
    (808) 521-7129
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    Original Message