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Bosendorfer Key Lead Expansion

  • 1.  Bosendorfer Key Lead Expansion

    Registered Piano Technician
    Posted 04-02-2019 18:07
    Couple of pictures of a tortured piano.  Bosendorfer 225, c1970s with expanding leads in both the keys and damper levers.  Every one of them binding against its neighbor.  Fortunately no apparent splitting of the keys.  Have not run into this on a Bosey before.  Seen it on other pianos though.  Remove and replace I guess is the order of the day.  Nasty stuff.  
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    David Love RPT
    www.davidlovepianos.com
    davidlovepianos@comcast.net
    415 407 8320
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  • 2.  RE: Bosendorfer Key Lead Expansion

    Registered Piano Technician
    Posted 04-02-2019 19:07
    Hi David. 

    We we have a LOT of expanding leads here in Hawaii. The consensus among the piano tuners here is that it's primarily the salt air that causes the leads to expand and corrode.  (Is this piano near the ocean? ).

    What's interesting is that not every lead in the piano is affected. Same piano, presumably leads that came from the same batch, sitting in the same environment for the same period of time,  but not not all of them are bad.

    There are are some brands that are notorious for lead expanding. But this is the first time I've heard of a Bosy having them. But then, there aren't that many around.

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    Willem "Wim" Blees, RPT
    Mililani, HI 96789
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  • 3.  RE: Bosendorfer Key Lead Expansion

    Registered Piano Technician
    Posted 04-02-2019 20:11
    Bay Area but Oakland Hills so not exactly a "salty air" environment. In this case all the leads are affected.

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    David Love RPT
    www.davidlovepianos.com
    davidlovepianos@comcast.net
    415 407 8320
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  • 4.  RE: Bosendorfer Key Lead Expansion

    Registered Piano Technician
    Posted 04-02-2019 19:53
      |   view attached
    File or belt-sand the keys one by one with FACE MASK, etc. I've done that with  many older pianos and never had them repeat (that I know of). Anyone know of catalyst that makes this occur? Salty seacoast air? I guess deciding factors: cost to owner, time technician has to order parts and do it? Some of us don't have workshops (Am I the only one?) How soon does it need to be performed on (Concert's next Friday?) "etc etc etc," said the King of Siam.






  • 5.  RE: Bosendorfer Key Lead Expansion

    Registered Piano Technician
    Posted 04-02-2019 20:43
    William. 

    Just filing them them will not stop future expansion.  The leads either have to be replaced, as David is doing, or do I do. I use a Fornster bit and drill the lead down to about 1/16" below the surface of the key. I then apply a generous amount of shellac to the leads.  You can also use lacquer, but prefer shellac. That more or less seals the lead from the environment.  

    Yes, difinately use a mask when working with lead.  I do this work at the end of the day. When I get done, all my clothes goes in the hamper and I take a shower and wash my hair.

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    Willem "Wim" Blees, RPT
    Mililani, HI 96789
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  • 6.  RE: Bosendorfer Key Lead Expansion

    Registered Piano Technician
    Posted 04-02-2019 20:52
    David, one thing you should ascertain is whether the leads are metric diameters or not. If they are, you can get metric sized leads from Yamaha.

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    Steven Rosenthal
    Honolulu HI
    808-521-7129
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  • 7.  RE: Bosendorfer Key Lead Expansion

    Registered Piano Technician
    Posted 04-03-2019 17:07
    Just a reminder.  Going to my.ptg.org and entering a search for "lead corrosion" will turn up same interesting past discussions.  Apparently, the potential causes are several, and this may lead to an explanation for the seeming inconsistencies of the corrosion's presence.  
    Claude Harding





  • 8.  RE: Bosendorfer Key Lead Expansion

    Member
    Posted 04-03-2019 23:43
    Ok, I read it and the description of lead bloom doesn't match what we are seeing. The leads are expanding and I don't see any white eruptions on the surface as described. Plus they are describing corrosion. Some of the expanding leads I have seen show no white. 
    I think it is an electrolysis caused by a bad mixture. This would explain the expanding pot-metal brackets on Young Chang actions and other uprights of the early 1900's





  • 9.  RE: Bosendorfer Key Lead Expansion

    Registered Piano Technician
    Posted 04-04-2019 11:07
    There is a fair amount of white powdery residue associated.

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    David Love RPT
    www.davidlovepianos.com
    davidlovepianos@comcast.net
    415 407 8320
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  • 10.  RE: Bosendorfer Key Lead Expansion

    Registered Piano Technician
    Posted 04-02-2019 23:01
    Mr.Love,

    I had the same thing happen on a Bosendorfer 225 from the same time period. The piano had been in Colombia for a number of years where it was re-finished. In this instrument it was only the underlever leads that corroded and I always suspected some sort of exposure to a corrosive gas during re-finishing. My thinking was that the keys and stack were removed while the back action was not. I found that .32 caliber wad cutter bullets (cylindrical and tin plated) were a near perfect fit for the originals installed by Herrburger-Brooks. I was lucky and only one of the underlevers had cracked due to the expansion. Bullets (as distinct from cartridges)  are easy to find at most local gunshops that cater to the re-loading crowd. Using them in a piano is perhaps the best use one could put them to in a swords to plowshares sort of way.

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    Karl Roeder
    Pompano Beach FL
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  • 11.  RE: Bosendorfer Key Lead Expansion

    Registered Piano Technician
    Posted 04-03-2019 05:38
    Karl

    What method did you use to extract the expanded lead?

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    David Love RPT
    www.davidlovepianos.com
    davidlovepianos@comcast.net
    415 407 8320
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  • 12.  RE: Bosendorfer Key Lead Expansion

    Registered Piano Technician
    Posted 04-03-2019 07:45
    I drilled through the leads with a 1/8th" bit over a bucket to catch the dust and most of them disintegrated to the point I could clean the hole with a bore brush. The few that didn't come out on their own I was able push out with a straight punch by hand. The key for me was coming up with a way to clamp the underlever in place to lessen the chance of damaging the wood. I was removing them from the rail in case that wasn't obvious.

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    Karl Roeder
    Pompano Beach FL
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  • 13.  RE: Bosendorfer Key Lead Expansion

    Member
    Posted 04-03-2019 11:07
    Really,, lead is basically inert as an element. Have you ever had a battery post expand? 
    The air surrounding the lead may cause some oxidation on the surface which happens to all metals but does copper or steel expand in salty environments?
    Also,,, I have seen this happen in the mountains where I live. The clue is when Will from Hawaii said it doesn't happen to all the leads.

    The answer,, The lead used in some of the weights was from recycled lead and was contaminated 
    Same as the Young Chang brackets and other pot metals that are mixed from what is available.

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    Keith Roberts
    owner
    Hathaway Pines CA
    209-728-2163
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  • 14.  RE: Bosendorfer Key Lead Expansion

    Registered Piano Technician
    Posted 04-04-2019 11:19
    Thanks Karl.  The question, of course, is whether it's necessary remove them or is it the exposed to the air part of the lead that is effected only.  If so, then removing the outer layers and sealing with shellac might be a remedy.  If the lead is, indeed, a bad composite then they would have to be removed.  I'll remove and replace since I don't know how to determine one way or the other.  

    Just FWIW, I'm not too worried about the size not matching.  Lead is easy to squeeze or hammer to the desired diameter with a final swedging to get them snug.  I would plan to use the smaller 3/8" (probably) for the underlevers and if they are too deep then they can easily be trimmed in advance with a pair of flush cut wire cutters (like the JNP-1 sold by Pianotek).  I use these all the time, btw, when I want to reduce the size and weight of a lead for various reasons.

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    David Love RPT
    www.davidlovepianos.com
    davidlovepianos@comcast.net
    415 407 8320
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  • 15.  RE: Bosendorfer Key Lead Expansion

    Posted 04-03-2019 12:35
    Mr. Roeder replied suggesting wadcutter bullets, and they're perfect in a lot of situations like these.  They come in various calibers (sizes).  My hobby is precision pistol shooting.  Normal bullets will make a jagged hole in a paper scoring target making it hard to read.  A wadcutter is a flat head bullet, as Mr. Roeder explained, and makes a perfectly shaped hole showing exactly where it hit.  A lot of folks use them for competitions because of that specific quality.  There's a lot of stuff in the "Pistol world" that helps in the tech world.  Among those are the cases, the lead, the hearing protections, and some of the CLP's for trap work.  If a CLP will withstand 500 degrees, thousands of movements, and still remain viable and smooth, you should see how it works on pedal assemblies, etc!  That's my two cents to add to the conversation.

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    Ted Rohde
    Central Illinois
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  • 16.  RE: Bosendorfer Key Lead Expansion

    Registered Piano Technician
    Posted 04-03-2019 22:15
      |   view attached
    For those who haven't seen this documentation on Lead Bloom, see attachment.


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    Steven Rosenthal
    Honolulu HI
    808-521-7129
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    Attachment(s)

    pdf
    Lead Corrosion.pdf   160 KB 1 version


  • 17.  RE: Bosendorfer Key Lead Expansion

    Registered Piano Technician
    Posted 04-03-2019 23:43
    Steven Rosenthal, Very interesting read about lead in Naval Models. Wood producing acetic acid and that Basswood is much higher in acetic acid than pine. New to me. Obvious moisture and cool air are strong contributors to the corrosion issue. 

    Confirms the wisdom of LightHammer Tone Regulation, (LHTR) that mostly eliminates the need for counterweights in keys. With LHTR we could switch to soft copper for counterweights and that would be healthier for everyone.

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    Edward McMorrow
    Edmonds WA
    425-299-3431
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  • 18.  RE: Bosendorfer Key Lead Expansion

    Registered Piano Technician
    Posted 04-04-2019 00:08
      |   view attached
    Keith, my experience is that this progresses from just expanding to slowly turning to white powder.
    Edward, apparently some companies are experimenting with using other metals. I've seen some key weights on newer, I think, Young Chang that are more silvery than lead, also was told that Yamaha has used something else on their hybrid  pianos.
    This is a key lead from an older Yamaha.


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    Steven Rosenthal
    Honolulu HI
    808-521-7129
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  • 19.  RE: Bosendorfer Key Lead Expansion

    Registered Piano Technician
    Posted 04-04-2019 17:30
      |   view attached
    David, if you're replacing a few leads then massaging ill fitting replacements isn't too bad. But if you're replacing all of them, keys and dampers, that's upwards of 300 leads and adds a lot of time to fuss with each one. That said, I've found that sometimes the expanding leads enlarge the holes to the point that replacements are quite loose so bigger leads might be useful. Again, that's if the Bosendorfer leads are metric.
    Here's what Yamaha has -or can get, last I checked.

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    Steven Rosenthal
    Honolulu HI
    808-521-7129
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    Attachment(s)

    pdf
    Yamaha key leads.pdf   508 KB 1 version