Harpsichord

Expand all | Collapse all

soundboard cracks

  • 1.  soundboard cracks

    Registered Piano Technician
    Posted 04-03-2018 22:32
    I am currently restoring a William de Blaise Cembalo Transverso harpsichord. (A customer gave it to me and I could not pass on it.) I'm at the point where I need to decide a course of action with the fine cracks in the soundboard. I plan to carefully dry the board down a bit tomorrow to see if they open a bit more. For the most part, right now there is only a very small amount of see through separation. At the belly rail the board measures about 2.5mm.

    So, I have a couple of what would you do questions: would you dry down the board and shim the crack with a wood shim or, fill it with a good epoxy? If I go with a wood shim, where can I get good spruce for the job?

    I tried an epoxy fill on a piano board years ago but I have not seen that piano in a long time. It was holding the last I saw the piano but who knows now. I could use a bit of faring filler to give the epoxy some color. In any case, this looks to be a bit of a challenge as I have no experience filling soundboard cracks on a harpsichord. Ah, give me a Challis aluminum board any day. Just kidding!

    ------------------------------
    [Don] [McKechnie,] [RPT]
    [Piano Technician]
    [dmckech@ithaca.edu]
    [Home 607.277.7112]
    ------------------------------


  • 2.  RE: soundboard cracks

    Posted 04-04-2018 06:33
    When I asked about a crack in the soundboard of 7 pedal Goble harpsichord at Gyndebourne Andrea Goble said 'don't worry about it' So I didn't. It's still like it some 20 years later. I have a Wm.deBlaise single manual - it lives under my Steinway. I've used it at all sorts of pitches - from 390Hz for Bill Christie's 'Les Arts Florrisants' to 415Hz 430Hz and 440Hz. at Glyndebourne - for rehearsals. It didn't seem to mind these pitch changes. I re-plectra'd it with Delrin - it had been leather - I simply cut the leather plectra off with centre-pin cutters, drilled a hole through and opened that hole out with a speacially prepared fine watch-makers file. All OK.  Michael

    ------------------------------
    Michael Gamble
    semi retired
    Brighton
    01273813612
    ------------------------------



  • 3.  RE: soundboard cracks

    Posted 04-04-2018 14:11
    Out of curiosity, I suppose you know these Wm de Blaise H'chorfds were built by Julius Bluthner?
    Michael

    Virus-free. www.avg.com





  • 4.  RE: soundboard cracks

    Registered Piano Technician
    Posted 04-04-2018 09:48
    Hi Michael,

    If I were keeping this instrument I would let the cracks alone but, since I plan to sell it I would prefer to address the problem now. I do not want a call back should the cracks progress. After thinking about it overnight, I am leaning towards a wood shim instead of epoxy. The traditional route seems the best. According to Zuckermann, de Blaise used Romanian pine, "a sort of spruce poplar in England till recently when the source dried up." (Copyright on the book is 1969 for dating purposes on quotes.)

    I plan to use Delrin instead of leather plectra as well. After my experience doing that conversion to the Challis I restored it just seems the best.

    By any chance, do you have a source that can give me the date of manufacture of my de Blaise? The serial number is 155. I'm guessing early to mid 60's. It has those ugly yellow plastic sharps. Later he started using a nicer looking white plastic.

    ------------------------------
    [Don] [McKechnie,] [RPT]
    [Piano Technician]
    [dmckech@ithaca.edu]
    [Home 607.277.7112]
    ------------------------------



  • 5.  RE: soundboard cracks

    Registered Piano Technician
    Posted 04-04-2018 10:22
    Don,
    For shim stock, I'd ask a harpsichord maker for scrap. Presumably there is a fair amount of waste when cutting out a soundboard blank, plenty to make shim stock for the typical cracks in the upper treble.
    Regards,
    Fred Sturm
    "When I smell a flower, I don't think about how it was cultivated. I like to listen to music the same way." Mompou









  • 6.  RE: soundboard cracks

    Registered Piano Technician
    Posted 04-04-2018 20:47
    Fred, I ordered some Swiss pine stock from Zuckermann. Seems like the best choice to go with an European wood. We'll see.

    What is your glue of choice these days to glue in a shim on a harpsichord board?

    ------------------------------
    [Don] [McKechnie,] [RPT]
    [Piano Technician]
    [dmckech@ithaca.edu]
    [Home 607.277.7112]
    ------------------------------



  • 7.  RE: soundboard cracks

    Registered Piano Technician
    Posted 04-04-2018 20:57
    Hi Michael,

    I did not know that. In his book, Zuckermann states that de Blaise "associated himself with the medium-sized firm of Welmar Pianos. I just did a quick search and found the following page. Is this the history as you know it?

    Welmar Pianos at the Piano Shop Bath
    The Piano Shop Bath remove preview
    Welmar Pianos at the Piano Shop Bath
    Welmar was a British builder established in London in 1876, the company existed until 2003 when the British Piano Manufacturing Company of Stroud closed its doors; they had owned the brand name since the 1990s.
    View this on The Piano Shop Bath >


    ------------------------------
    [Don] [McKechnie,] [RPT]
    [Piano Technician]
    [dmckech@ithaca.edu]
    [Home 607.277.7112]
    ------------------------------



  • 8.  RE: soundboard cracks

    Registered Piano Technician
    Posted 04-04-2018 22:42
    I've never shimmed a harpsichord board, but I think I would use fish glue.
    Regards,
    Fred Sturm
    "The true sign of intelligence is not knowledge, but imagination." - Einstein






  • 9.  RE: soundboard cracks

    Posted 04-08-2018 03:16
    Hello Don - I'm on holiday on the North Norfolk Coast right now with nothing between us and the North Pole (literally) so I'm just going by memory. When I get back to base in Sussex I'll look up the de Blaise info and let you know what I find.
    Michael

    ------------------------------
    Michael Gamble
    semi retired
    Brighton
    01273813612
    ------------------------------



  • 10.  RE: soundboard cracks

    Registered Piano Technician
    Posted 04-06-2018 13:55
    I ordered fish glue from StewMac and found this chisel on the site. It looks like it would be a nice tool for chiseling down a shim. I ordered  one to give it a try.
    Two Cherries Guitar Brace Chisel
    Stewmac remove preview
    Two Cherries Guitar Brace Chisel
    A better shape for a delicate job. The unique "S" profile of this chisel is perfect for carving the gently curved ends on guitar braces. As the cutting edge follows the curve, the handle is lifted up to make room for your hand.
    View this on Stewmac >


    ------------------------------
    [Don] [McKechnie,] [RPT]
    [Piano Technician]
    [dmckech@ithaca.edu]
    [Home 607.277.7112]
    ------------------------------