Frame Cracked Twice, Engineering help?

[Greg Granoff]

Roger C Hayden wrote:

> OK, Guys, I need help
>
> Hazleton Bros. 5'10"  Grand.  Neatly rebuilt, (by me).  Too little
> downbearing in the treble, so I lowered it a bit.  (I've Done such things
> before.)  Brought up the tension nice and evenly, installed dampers,
> sounding good at A-440, ready for fine tuning.
>
> During the Fine Tuning:   THWUNK !!  I couldn't see anything, so I played
> a chromatic scale.  It climbed nicely until I passed the last strut, and
> dropped a fourth.  Then I could see the crack, travelling toward the
> Northeast, but holding near the edge of a circular sound hole.  I QUICKLY
> dropped tension on that section, and then dropped the rest of the piano.
>
> Fortunately this pinblock is only attached to the frame, and not to the
> case, so I loosed everything, pulled out the frame with the block and
> strings intact, and called a welder who assured me he could handle this.
>
> Re-painted, reinstalled, strings back in place, tension up to A-440 and
> holding.   Last Friday before bed I played a chromatic scale again, and
> it wasn't chromatic. . . . . .  So I dropped the tension on the last
> section and went to bed.
>
> There's more to welding cast iron then I knew.  My welder did not heat
> the plate, nor cool it slowly, as I hear is necessary.  And I've heard
> from a far more skilled fellow, that this kind of welding is very much an
> art.
>
> Question:  What if I had a steel plate created, and with PC-7 between it
> and the underside of the frame to give it strong frictional contact,
> drilled, tapped and bolted  this plate in place below the cracked area.
> It would be out of sight, and providing considerable strength for that
> area.  Would this be sufficient to bear the tension and give us our whole
> piano back?
>
> Roger C. Hayden, RPT
> Clarks Summit, PA
> ________________________________________________________________

Roger,
I've included a link to a site which promotes an intriguing and apparently
extremely successful
variety of cast iron repair.
Haven't talked to them, but I understand that they have done piano plates and
consider their procedure highly appropriate.
It might be worthwhile to check with them, regardless of what you ultimately
do.
Good luck!

Greg Granoff

Here's the address:           http://www.locknstitch.com/