CAUT

  • 1.  Hidrau bench

    Registered Piano Technician
    Posted 06-12-2024 17:25

    Recently I have come across three Hidrau benches with a noise problem when adjusting up or down. All are in piano teaching studios and get a lot of use. The noise is best described as a metallic scraping sound. All three of these benches also have worn bench top coverings that are flaking off in fine particles. I believe it is possible that some fine particles from the worn top have found their way into the pneumatic system thus creating the scraping sound. One of these benches is particularly loud. I contacted Hidrau and was told they have not heard of this problem.

    Hidrau does acknowledge the worn top problem and will sell a new top if the customer wishes. For now, all three benches have fitted covers over the top. They believe that the recent upswing in deteriorating bench tops is due to the use of antibacterial solutions used during the pandemic. 

    Has anyone observed this scraping noise and if so, were you able to eliminate the noise? Hidrau suggested I try a little bit of WD-40 Specialist White Lithium Spray. I am a bit concerned about using this spray but may try it is no other good solution comes along.

    WD-40 Specialist Protective White Lithium Grease Spray with SMART STRAW SPRAYS 2 WAYS, 10 OZ 

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    [Don] [McKechnie,] [RPT]
    [Piano Technician]
    [dmckech@ithaca.edu]
    [Home 607.277.7112]
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  • 2.  RE: Hidrau bench

    Registered Piano Technician
    Posted 06-13-2024 05:35

    We have hundreds of these benches at Juilliard. I've been applying TFL-50 wet between the posts, and that has helped keep them returning (up) when they got slow or stopped returning. We haven't had scraping noises though. The other spot where TFL50 helps is where the adjustment lever pivots under the seat. This frees the lever to return readily.



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    Mario Igrec, RPT, MM
    Chief Piano Technician, The Juilliard School
    http://www.pianosinsideout.com
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  • 3.  RE: Hidrau bench

    Registered Piano Technician
    Posted 06-13-2024 07:31
    I've heard the noise too, I think I used some McLube 444 from my tool bag, but whatever I used, the noise went away. It seems odd that flakes from the top would make it into mechanism underneath, they might be right about cleaners being the cause, or maybe it was just material that didn't hold up. I took top to a canvas awning shop in the area, they replaced the foam and leather with higher quality materials. Last time that cost $150, which I think was less than a new top from Hidrau.
    David Graham
    Graham Piano Service, Inc.
    512 S. Main St.
    Sycamore IL 60178
    815-353-5450
    Riding again in Bike 





  • 4.  RE: Hidrau bench

    Registered Piano Technician
    Posted 06-13-2024 19:53

    Thank you David and Mario. I will try one or the other lubricant when I have the opportunity.



    ------------------------------
    [Don] [McKechnie,] [RPT]
    [Piano Technician]
    [dmckech@ithaca.edu]
    [Home 607.277.7112]
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  • 5.  RE: Hidrau bench

    Registered Piano Technician
    Posted 06-14-2024 08:32

    I would be careful about mcLube444 in this application. Its solvent is extremely aggressive and might eat the seal on the pneumatic cartridge. But I have no idea how it all looks inside and whether the seal is vulnerable, just that spraying a lubricant helps.



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    Mario Igrec, RPT, MM
    Chief Piano Technician, The Juilliard School
    http://www.pianosinsideout.com
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  • 6.  RE: Hidrau bench

    Registered Piano Technician
    Posted 06-14-2024 10:09
    McLube 444 is no longer available, with McLube 1725 substituted. Its solvent is less aggressive, and it seems to have similar if not identical lubricating/coating capacity.

    Regards,
    Fred Sturm
    http://fredsturm.net
    www.artoftuning.com
    "One's real life is so often the life that one does not lead" (Oscar Wilde)