How best to repair and/or reglue strip

[Foamy]

Not sure what this piece is called. It follows the seam of the halves of the back.

You can see from the picture that it has lifted. Doesn't look like there is any glue there at all.

What's the best way to fix this?

It looks like the strip is actually too long! I could put some glue there and force it down - the wood appears soft enough to do that. And since it's so soft, I can't imagine it exerting enough force on the back.

Or should I take an Exacto, slice it and trim it a bit so it sits flat before regluing?

Is the purpose of this strip only to support the seam?

Thanks!

[202dy]

That is a brace. Not only does it support the seam, it adds significant strength and stiffness to the back. Left loose, it can be the source of a really annoying rattle. It should be re-glued.

Assuming that the guitar in question is of decent quality the strip is correctly cut to length. Do not trim.

The most difficult part of the repair is removing the dried glue. It is (probably) on both the bottom of the brace and the inside of the back. Small scrapers, like those made from razor blades, shim material, or even old palette knives are the best choices. It might appear that using sandpaper would be a good idea. Do not do it! Sandpaper can tear and get lodged between the brace and the back. That will create three times as much work because it will have to be removed before gluing. A damp rag can be used to clean up any residue when scraping is done.

Once the glue is removed and cleaned up devising the clamping rig is the next problem. This is a perfect job for a go-bar table. Most luthiers and repairman will default to any number of clamping arrangements. One of the better ones will be to use a brace repair jack(s) between the top and the brace. When you have chosen the clamping method, a dry run or two are in order.

Either white or yellow glue are good choices for this job. White glue has an open time of roughly seven minutes. Yellow is about five. Apply the glue with a spatula to the brace and back. Place the clamps and apply pressure on the brace until some glue squeezes out. Clean the glue with a damp rag. Continue the clean up process for a couple minutes. The glue will stop oozing. Allow to cure overnight. Speaking of glue, if the glue on hand is older than about six months, throw it away and buy a new bottle. This is not a job you want to do twice.

Remove the clamps, do some final cleanup. String it up and play.

This job will take an hour for a skilled tech, maybe longer depending on whether or not the initial cleaning process shows more problems or creates more as the brace is lifted. This task requires patience. It also requires some woodworking skill. It will probably require some tool purchases. All of which point to the cost effectiveness of using a professional to perform the repair.

In any event, if think changing a tire is working on a car, have to look in kitchen drawers to find some tools, or think a tool is a piece of software, find a good tech to do this one. You'll be glad you did.

[Foamy]

I'm a woodworker with a shop full of woodworking tools, so I can work up a scraper along the lines you describe.
I underestimated the importance of that strip.
I can get an inspection mirror and a flashlight in there to see what's left of any glue there now - I'll be surprised to find much, if any.
Thanks for the details. I had not thought of most of what you posted, and I'll be sure to take it slowly.
The only concern I have is the length. If I press with my fingers, the raised part does move, sort of like a bubble. But with enough pressure and clamping, I can make it flat.
Thanks much, and I'll get to it!
:-)

[202dy]

You should do fine. The amount of glue residue will define the failure. A little residue means the joint was starved. A lot usually indicates failure from mechanical shock. The braces are supposed to be tight against one another. What you're feeling is evidence that it was done right at the factory.

A mirror and a light are essential. While you're in there, examine the rest of the braces. If the strip came loose because the guitar took a hit, there could be more loose braces. Don't forget to check the braces on the top. It's not much fun to work inside an acoustic body. If there are other problems you will want to button it up in a session or two.

Good luck.

[Foamy]

Originally Posted by 202dy

You should do fine. The amount of glue residue will define the failure. A little residue means the joint was starved. A lot usually indicates failure from mechanical shock. The braces are supposed to be tight against one another. What you're feeling is evidence that it was done right at the factory.

A mirror and a light are essential. While you're in there, examine the rest of the braces. If the strip came loose because the guitar took a hit, there could be more loose braces. Don't forget to check the braces on the top. It's not much fun to work inside an acoustic body. If there are other problems you will want to button it up in a session or two.

Good luck.

To be clear, all the braces look good and feel good. By "braces", I mean the 1/4" thicker pieces that go across the back and front.
The only one that's loose is that thin 1/32" strip that follows the seam. Looks like there was almost zero glue there.
Thanks!