Loose and cracked Braces, Which glue?

[nathan clark]

I'm looking for input from the seasoned pros out there who have practical experience with this specific repair.  Do I have the right approach?  Which glue?

I'm working on an early 1960's Gibson Hummingbird where the cross brace on the treble side upper bout is loose and its two flat-sawn neighbors (the upper face brace and a finger brace) are split at the feathered ends.  The huge pickgaurd shrank warping the top across the grain which caused the brace issues.  

I clamped the top flat with some c-clamps for a few weeks and the top is now remaining flat (for the past few hours, anyway) with the clamps removed.

My thinking:

1) lightly sand the loose x-brace and related area of the top with a couple of pulls of 220 to "freshen up" the gluing surface without trying to actually get rid of the old glue. 

2) glue and clamp all three braces (one per session) with hot hide glue.

3) break out a small piece of the lining at the end of the x-brace and fill it in with a piece of mahogany that sticks further out from the sides in order to catch and hold the x-brace.

4) lacquer the top and reattach the old PG with the usual double sided adhesive.

[Greg Mirken]

I usually use Titebond for work such as this because it's really tough sometimes to get hot hide glue spread along the brace and get everything clamped up before the glue gels. Either would be stronger than the original factory glue job, I'm guessing.

[Hesh Breakstone]

+1 Titebond Original.  If getting the glue in there and the clamps all set in place takes more time then the HHG requirements Titebond Original is a good choice.

[nathan clark]

I clamped the top flat and left it for a few weeks.  It stayed that way when I finally pulled the cauls and clamps.  I went with hot hide glue for the braces.  The braces were easily accessible through the sound hole.  I glued and clamped them one at a time without incident.