Kalamazoo mandolin repair

[Dave Richard]

Hi, this KM-11 mandolin belongs to friend. He has loaned it to me, and I noticed the severe caving of the top, and found two cracked top braces.  My query is how best to repair them.

The cracks are old, I think, and have contributed to the sinking, which is worst below the pickguard on the treble side.  The braces are both splitting at the bevel, near the lining: the one below the guard is worse, and the other is far back in the body.  If the top was still flat, I think it would be a simple matter of gluing and clamping the splits.  But since the top is so deformed(below the guard), I think it's a question of removing the back, flatten the top(somewhat), and then glue the splits.

Suggestions?

 

Thanks, Dave

[FRANK]

get the best view you can knowing is 90% of the battle

[Paul Breen]

Have you tried dry clamping yet to see what happens? I would do that before resigning to pulling the back.

[Dave Richard]

I hesitate to even dry clamp the area, as the distortion is so severe...

[Paul Hostetter]

I've dealt with these several times. The top is collapsing because the bracing is loose. You can try to simply reglue it/them, but it's not a guarante of restored health—it's a flaky design to begin with. My best success involved removing the back, admittedly a messy proposition, then springing in radiused braces that were locked into the kerfed lining. And I used just a simple robust X for the bracing, rather than the original ladder+diagonals. Getting the back off unscathed will be the hard part. Good luck!

 

But try regluing the current bracing first—don't worry about forcing the top back flat. Just be steady and gentle, it'll go.

[Dave Richard]

Paul, your suggestions sound very good, I'll present them to the owner.

 

Thanks all for the replies.