Vertical Frame Separation

[BSimon1234@AOL.COM]

Mr. Blees wrote:

<< But I have found that for one, trying to clamp the crack is
almost impossible, and 2, it really doesn't make any difference. What you are
trying to do is keep the crack from getting worse. The piano has been tuned (I
presume) with the crack there, and so it really won't effect the tuning any.
>>

I don't know why anyone would not want to permanently repair this separation,
and prevent its extension in the event the bolts ever loosened.  To have
"stasis" of the open crack seems to me to be questionable because in different
humidity conditions the crack might even close up a bit and cause instability
of the tuning.  The crack may continue downwards, away from the bolts, or get
worse fast when trucked about in a move. 

I have repaired perhaps ten separations like the one mentioned, and found that
in every case big C-clamps or pipe clamps ( with wood pads to distribute the
stresses) every 4 inches were more than sufficient to put things together.
Take up the stress evenly with all clamps. In cracks wider than 1/16th inch I
also reduced tension. 

I use thinned"original" Titebond glue, not type II,  in the separation, and 6"
long, very thin artist pallet knives  to work the glue into the crack (and
because I am in very dry Phoenix)  sometimes wetting the crack with water
first so the wood does not suck the water out of the glue and greatly thicken
it before clamps are on and closed.  If the crack extends through the back
beam, and the tip of the pallet knife can be seen poking through between
posts, consider a lag bolt from the back for the bottom of the crack.

Drilling the holes can cause wood chips that fill crack, impeding its re-
lamination. I use compressed air to blow these out, chased by the pallet
knife. ( I have a portable compressed air tank and needle extension nozzle.)

I think all of the separtations I have seen were in laminations just behind
the pins. The pins, after all, do act to hold together the laminations they
penetrate.  For a separation that exposed portions of the pins I think I would
use a very thin and slow epoxy or a very slow CA glue instead of the Titebond,
as these have been shown not to diminish pin torque.

I leave it a day, then come back to remove clamps  and tune. This is
undoubtably more inconvenient than throwing in a "stabilizing" bolt and
tuning, but I feel it is the "proper" repair.

There is no reason to go larger than 1/4" bolts. 

Bill Simon
Phoenix