Loose brace

[Henning]

Hello, can anybody please give some clues and hints?
I have a Yamaha guitar (CG made in Taiwan) and wonder if anybody please knows what glue was used in those guitars?
One of the braces is not completely attached to the top and I am considering trying to re-attach it.
https://www.acousticguitarforum.com/...d.php?t=514171

Best regards

[redir]

I don't know what kind of glue they use on those but as far as dust is concerned in the tread you linked too, it's a good idea to vacuum it out before repairing the brace. You will need to shove glue up under the brace and you don't want to push dust in there with it. Titebond glue would most likely work fine here. If you can you would want to get a strip of sand paper under the brace and sand both surfaces. Tape off both sides of the brace to protect the top and inject glue along the brace/top joint and use a thin spatula to shove it under the brace. Remove the tape and clean up with a wet cloth and clamp the brace over night.

You could also use CA if you wanted too and it would be quicker but harder to clean up and the possibility of making a big mess.

[charles Tauber]

Unless a brace is completely removed, I don’t attempt to remove old glue from brace surfaces, or try to “smooth” gluing surfaces. It’s been my experience that “regular” wood glues adhere “well-enough” to old glue, sufficiently well that in more than three decades of doing so I’ve never had one fail.

[Henning]

Originally Posted by redir

You could also use CA if you wanted too and it would be quicker but harder to clean up and the possibility of making a big mess.

I actually once called a local violin and guitar builder/repairman and suggested to use CA inside the guitar. He then said in a very strong almost aggressive voice: "are you crazy, you might get your fingers stuck inside your guitar!".

I realize there is a glap of about ~1 mm between the top and the brace. It has probably been loose quite some time.

[redir]

Originally Posted by Henning

I actually once called a local violin and guitar builder/repairman and suggested to use CA inside the guitar. He then said in a very strong almost aggressive voice: "are you crazy, you might get your fingers stuck inside your guitar!".

I realize there is a glap of about ~1 mm between the top and the brace. It has probably been loose quite some time.

Always keep the acetone nearby

[charles Tauber]

Originally Posted by redir

Always keep the acetone nearby

Just wear rubber gloves.

[redir]

Originally Posted by charles Tauber

Just wear rubber gloves.

The lack of tactile senses when working inside the soundbox blind kills me with rubber gloves. Of course that is a great tip, they do indeed work fantastic but in some cases I just can't do it and prefer to rely on flow control and a bit of acetone just in case. So far I've yet to end up in the ER with a very long and elaborate story that no doubt they have not heard before.

[charles Tauber]

Originally Posted by redir

The lack of tactile senses when working inside the soundbox blind kills me with rubber gloves.

I wear thin surgical-type gloves whenever I work with CA glue. They provide full feeling: the only thing they prevent me from doing is putting glue under my thumbnail and using that as a dispenser, which I don't do anyway with CA glue.

[Henning]

I find the only clamp I have that reaches in so far is the rather heavy Werus that weighs ~1,6 kg.
I fear that it might cause tensions in the top if using. It is also rather difficult to use for this application, apply correct pressure etc.

[charles Tauber]

One or more popsicle stick sized pieces of wood that are slightly longer than the depth between brace and guitar back can be wedged against the back to provide clamping force for the loose brace. Don’t over do the wedging force as only light pressure is required. If desired you can apply light pressure on the outside of the guitar with a clamp across the popsicle stick(s).

[redir]

To illistrate what Charles is saying with pictures this is how I re-glued these back braces on an old 000. I make the columns so they fit with just a bit of pressure because I don't like to push up hard on the top. IT's best if you can press up against a top brace but sometimes you cannot.



And then to increase the pressure I clamp from the outside with a back slat caul to take the curvature of the back brace.

[Henning]

[QUOTE=redir;5764373]. IT's best if you can press up against a top brace but sometimes you cannot.

Yes, thank you guys.

Is that a spruce top?

[redir]

[QUOTE=Henning;5764393]

Originally Posted by redir

. IT's best if you can press up against a top brace but sometimes you cannot.

Yes, thank you guys.

Is that a spruce top?

Yeah it's spruce but it's kind of hard to tell isn't it. God knows what this guitar has been through, it's a '44 Martin 000 that looks like it got hit by a truck but the owner loves it, and it did sound pretty good still too. Needs a neck reset, new frets, crack repairs and all the back braces were loose.

[Henning]

Lots of work to do with it, isn´t it?
Has it been sitting for a long time in the sun to get that "tan"?
I like the shape it has.