Pianotech

  • 1.  sizing damper guide bushings

    Registered Piano Technician
    Posted 01-12-2018 11:49
    Hello all,
    I remember from a conference the technique of sizing grand damper guide bushings by applying Profelt, inserting #7 bridge pins, and then letting them dry overnight.

    I've been servicing an old grand, a 1921 Packard, that suffers from damper wires that are dirty and corroded. I've done a quick treatment of Protek on the wires, but I'm sure many will start to stick again, so I've told the owner I'll likely have to remove the dampers and steel wool and polish the properly. I may even try to sell the owner on replacing the felt, which is old, crusty, and ineffective at damping.

    The fit seemed to be ok and simply cleaning and lubing the wires will likely do the trick. My question is, if I'm going to be taking them out anyway, is there any benefit to sizing them with Profelt as I described? Does anyone do this as a matter of course, and does the Profelt provide extra lubrication? Do #7 bridge pins usually work? I have them in stock, but not other sizes and haven't yet measured the wire size.

    thanks​​

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    Scott Cole
    Talent OR
    541-601-9033
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  • 2.  RE: sizing damper guide bushings

    Registered Piano Technician
    Posted 01-12-2018 11:58

    Yes, it's a good job to do. #7 bridge pins and Pro Felt should do it. Flitz the damper wires and there you go.

     

    Good luck

    Paul

     






  • 3.  RE: sizing damper guide bushings

    Registered Piano Technician
    Posted 01-12-2018 12:02
    #7 bridge pins have always worked for me. I size with alcohol, and it seems to work fine.

    I don't usually like using a product in bushings or hammers when I don't know what is in it, especially if something simpler, like vodka, will work, and not leave anything behind. 

    I'd use Flitz on the wires.



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    Susan Kline
    Philomath, Oregon
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  • 4.  RE: sizing damper guide bushings

    Registered Piano Technician
    Posted 01-12-2018 12:03
    Scott,
    #7 pins are right for many, but not all, grand damper wires.  Mic the wires, use the next larger bridge pin.

    I don't use steel wool - although the scratches it creates are very fine, they are still scratches.  I've never run into damper wire corrosion that couldn't be polished out with Flitz.  Works on the damper head finish, too.

    VS Profelt might work.  I've always used 70% Isopropyl, with good results.​

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    Michael Spalding RPT
    Fredonia WI
    262-692-3943
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