Recrowning- a method that works

[Erwinspiano@AOL.COM]

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In a message dated 5/25/2002 5:27:10 AM Pacific Standard Time, 
wayne.hohle@sympatico.ca writes:


> Subj:Re: Recrowning the soundboard,something different 
> Date:5/25/2002 5:27:10 AM Pacific Standard Time
> From:<A HREF="mailto:wayne.hohle@sympatico.ca">wayne.hohle@sympatico.ca</A>
> Reply-to:<A HREF="mailto:pianotech@ptg.org">pianotech@ptg.org</A>
> To:<A HREF="mailto:pianotech@ptg.org">pianotech@ptg.org</A>
> Sent from the Internet 
> 
>     Wayne and all

    I have recrowned boards in some old uprights and in so doing ended up 
with as much crown and as a new board. This method is only applicable if 
certain conditions are in evidence. 
  The most important one is that the rib joint needs to be separating so that 
all the rib glue joints can be separated from the board except at the 
liner/case edge. If the rib joints are bad a slim pallet knife can be worked 
under between rib and board while working it and pounding gently with a 
rubber mallet(on the board) to help undo the tight spots. If some rib 
splitting occurs don't panic come at the joint from the other direction with 
the grain to limit the splitting. Hey it's all getting glued back together 
any way!!!!!
 Once all ribs or at least most are free make sure the board is glued tight 
to the case edge. Dry the board down to 5% EMC or more. Open up  at least two 
shimming slots(spurlock method) along the grain from one side to the other on 
 the front side. Plate is out. One should be above the long bridge the other 
between long bridge and bass bridge. You could use more if needed.
    Locate rib joints on the front side and scribe a line on the board 
showing the center of the rib glue joint. This will be where the 5/8ths dry 
wall screws are inserted later every 3 or so inches.A pilot hole must be 
drilled thru the board and into the rib to prevent splitting.
   With the board dried down and the piano on its casters begin to glue one 
rib (cold hide glue only) at a time back to the board using maple wedges 
between back post and rib to force the rib against the board. The shim slots 
let the panel expand when you do this.
   Put the screws in from the front side into the rib.  Proceed to do this 
one rib at a time till all  are screwed/glued and  tight. Use as many wedges 
as you can get in to simulate a round belly. Does that make sense? The screws 
stay in
   Allow to dry . Keep it dry along with your Spurlock shaped shims. Install 
shims and let dry overnight.
     Yes its a version of compression crowning ,So what. It works and the 
piano will sound great and last another 20 years with more belly than it had 
new and you'll be a hero too.
   The first time I did this I expected the board to come flying back at me 
when the wedges came out. Nothing moved a stitch!!!!!!! I had a huge belly in 
an old board for less than a thousand dollars worth of time.
   Really this has a very uncompromising soundwith great sustain and real 
downbearing values. This in my opinion is a legitimate sounding 1912 ish 52" 
old oak upright.
   A good way to salvage many old sentimentally attached to family  uprights 
without the cost of a new board.
    I'll be gone the rest of the weekend. Post any questions and I'll respond 
later in the week.
  Hope this is useful.
Best>>>>>Dale Erwin

> 
> hi list
> a recent chapter meeting our host explained that he improved sound board 
> crown
> by cutting through the  treble-tenor bridge, perhaps in two or three 
> places, to
> the soundboard. then he placed a heavy beam across the rim and with a
> turniquiot[spelling?} pulled the sound board up to open up the cuts in the
> bridge to a predetermind measurement. then he taped of the side of the 
> bridge at
> the cuts and filled them with west epoxy to dry overnight. the next day he 
> would
> remove all the stuff and go on to rebuild the piano.  he says the tone is 
> nicely
> improved.
> any thoughts
> wayne
> 
> p.s. is there really  20 tons of pressure on the soundboard or is that on 
> the
> frame and the pressure at downbearing at the bridge is something different
> 


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