Gluing sound board cracks back to ribs.

[Roger Jolly]

Hi Ric,
          A couple of thoughts for you. Trying to pull a curled panel back
on to the ribs is not usually that successful. There's just not enough
material in the panel for the screw to get a real pull without stripping.

 A few suggestions. drill a pilot hole thro the rib and board,  a larger
(1/4") clearance hole drilled thro' the board, use a sound board button or
large diameter steel washer and a $8 screw from the front side of the
board, the rib will usually give you enough material for the screw to suck
the panel back on to the rib.  In Canada we use Robertson screws, square
indent, they don't fall off the driver when you thread them thro' the strings.
Once every thing is dry fitted, glue and leave 24hrs to dry, drill 1/4"
holes and then dowel.

I have another jig, a piece of scrap pin block with a routered out cup on
the bottom side to fit the ribs and two tuning pins on top.  thread a #15
piano wire thro' the crack and around  a half round piece of maple dowel 1"
back thro the crack. Torque up the pins and it will usually pull the board
back.  A few tips, 1. use a small piece of double sided carpet tape to
lightly stick the half round to the board. 2. bend the wire in half and
thread both ends from the front side of the board.

Not so easy to discribe with out the use of my hands, or pictures.  If you
have plate struts in the way, get creative with some wedges between the
board and strut. Some times you get lucky.

Two people can be useful with this kind of job just to hold things in place.

Hope this helps.
Ric




At 07:59 PM 12/02/00 -0600, you wrote:
>The problem is a cracked soundboard, and one side of the crack has
>pulled away from the rib about as far as to slip a business card
>through if it were cut in half.    This is in a full sized upright,
>player piano actually.  I must make any repair from the rib side.  
> 
>	The repair I am most familiar is drilling a pilot hole through the
>rib and SB, then drilling a body hole through the rib, stopping the
>bit with ground down hack saw blade, or old palette knife. Then
>smearing glue into the crack with the thin blade and running the
>screw in. 
>	Schaff (new catalog) offers a "sound board toggle" p 82.    Do I
>understand  these are left in the piano after the repair is
>completed?  Or is there a way to remove them and fill the access
>hole with a dowel? On p. 62 is a "soundboard repair clamp".  (wire,
>locking nut and wingnut) But this looks like one must have access
>to both sides of the soundboard.  Is this correct?   Both of these
>appeal to me because it looks like they can draw the seperation
>together with more strength than a screw through a 1/4 inch of
>spruce.  
>	If any one has used these repairs and can advise, I would be most
>grateful.  Or perhaps there is something out there I am not aware
>of.   I know of the repair in Reblitz using thin bolts and washers
>but  that needs access to both sides which I do not have. On p.
>128, illus. 7-14 is the exact problem I am facing. One side of the
>crack has curled away, the other seems intact.  Should I screw down
>the other side to be safe?  ---ric 
> 
Roger Jolly
Saskatoon, Canada.
306-665-0213
Fax 652-0505