Brace gluing help

Brace repair/gluing advice needed

Hi folks,

I need help with a repair job. I would like to do the repairs myself rather than send it out.

Specifically, I am looking for some guidance on applying pressure to the end of a top brace that has come away from the top, about an inch from the bass side of the lower bout...it seems that the glu has dried out, or was not applied to proper saturation at the brace endpoint. I would like to fix this problem and restore the uke back to proper integrity and playability.

I've known about the Scissor Jack ($98) from StewMac:


https://www.youtube.com/watch?v=E9YN3B8AG2A

Product page: http://www.stewmac.com/Luthier_Tools/Types_of_Tools/Clamps/Scissor_Jack.html

I was hoping to find a less expensive, alternative tool, or other method than setting a post against the brace, similar to how violin luthiers set the soundpost, which I've done successfully on another, similar repair (1950s Harmony Baritone), but it was tricky, fiddly and very time consuming to get a dowel rod cut to just the right length, positioned so it would not fall out, and nevermind apply glue without making a runny mess inside.

It's like the 'ship in a bottle' problem as you cannot get your hands inside the soundhole, so everything has to be done via some kind of extension.

Yes, I have removed the pickup jack and via that hole, when I shine a bright light on the top and into the soundhole, I can see the brace move away from the top when I press on the top above the brace, and the uke has lost nearly all bass frequencies, has little volume and sounds pretty dead. The strings are completely floppy so as to apply no tension to the bridge as of now.

If the common wisdom, is just to buy the right tools, and hope for the best, then I will resign myself to doing that, but keep in mind that I have zero intentions of doing this kind of thing for other than to maintain my own instruments. I do not plan to go into business for instrument repair. (maybe for some of you, those were famous last words)

Please advise as to the above. I am open to all suggestions.

Thanks in advance for your time and consideration.

A small turnbuckle might do the trick.
A spring held compressed by stringand cut the string at the right time.
A build your own cam clamp to fit. https://youtu.be/JSO5QFQhQk8

I have a very large collection of C-clamps with various reaches, and usually one of them will do the trick. The light weight bridge clamps from StewMac are good for this type of thing, and they come in quite a few lengths.

Titchtheclown said:

A small turnbuckle might do the trick.
A spring held compressed by stringand cut the string at the right time.
A build your own cam clamp to fit. https://youtu.be/JSO5QFQhQk8

Click to expand...

Thanks for the suggestions, I'll look into them.

How would one be able to rotate the turnbuckle? I can barely get 2 fingers inside deep enough to reach the area needing repair. 'Ship in a bottle' problems here.

Allen said:

I have a very large collection of C-clamps with various reaches, and usually one of them will do the trick. The light weight bridge clamps from StewMac are good for this type of thing, and they come in quite a few lengths.

Click to expand...

Thanks for your thoughts Allen.

I just looked at all the clamps on StewMac and also LMII. I'm not sure I can use any of these clamps.

The brace in question is the one that goes across the lower bout, between the soundhole and bridge on a concert uke. If I measure diagonally from the end of the brace where it needs to be glued, to the end of the inside edge of the soundhole at the treble side of the upper bout, it is 3.75".

The StewMac clamp with the shortest reach is 4.5", the smaller of the two in this photo:



seen here: http://www.stewmac.com/Luthier_Tools/Types_of_Tools/Clamps/Camless_Clamp.html

With my limited experience here, it seems that were I to use this clamp, likely it will have to be (permanently) modified for this repair (reach made shorter), unless there is some way to put a wider 'foot' on the end of the inside arm of the brace so that it can apply pressure right at the area needed.

I am open to suggestions.

To make my own clamps, I will have to buy even more tools just to craft them in the first place. Right now, I'd rather focus specifically on tools that are directly used to repair the brace. Maybe the local hardware store has clamps with shorter reach? I will check tomorrow.

A couple of largish "Rare earth magnets" Neomydium type will do it... glue one magnet on the end of a bent stick to help locate the postion.

I've done a few attempts on ukes. It is tricky but maybe you can get some better idea by looking at what I did.

http://argapa.blogspot.se/2010/05/crack-attacker.html

http://argapa.blogspot.se/2013/04/brand-new-crack-attacker.html

(The second link goes to the most viewed blog post of all, there was a link to it from some shady p*** site for a few months. Traffic soared but I think many were disappointed to find that my crack attacker was nothing more than a, well, crack attacker.)

Also, the small clamps I use are called f-hole clamps. I got them from www.metmusic.com and like them a lot. I see they cost 16 bucks.

http://www.metmusic.com/tools/clamps/50117-4/f-hole-clamp-4/

And being easily distracted from my day job I couldn't help thinking about turning that turnbuckle. Maybe if you wound some string around it and pulled the string to turn it after getting it into place..?

Good luck man.

Booli, I think Allen's first solution is the best. Just go to the hardware store and find a clamp with that reach. Put some cork or soft thick cardboard on the end that goes inside the uke and notch it so it won't slip off the brace. Cover the cork with tape so it won't stick to the glue. Use a flat board to spread the load on the top to keep it from deforming. Put some thin cardboard on the board to keep it from scratching the finish.

But probably the most important thing to do is get any old glue off or the new repair won't last long. Try run a strip of sandpaper in there. Run it top and bottom.

Do a dry fit before you glue.

To glue it put the glue (Titebond original is fine) on a thin strip of plastic like a piece of the side of a cheap yogurt container and force it into the crack. Be generous. You might have time clean up around the brace. Leave it clamped overnight.

An inspection mirror with LEDs is useful for quickly seeing where you put the glue.

Good luck.

Thanks Timbuck (Ken), Sven and the other Ken for all the suggestions. These are some great ideas for me to explore. Your experience being shared is much appreciated.

To sand off the old glue, I'm thinking to use a short-handled old butter-knife (one without teeth of course), bent at a slight angle, and put an adhesive strip of sandpaper on one, or both sides and get in under the separation. If I press down on the top a bit, the brace opens up maybe 2-3mm at the tip of the brace and maybe 1mm where the glue is still solid (kind of like a right-triangle), and this opening is about 20mm long in total, but all measurements are just by eye and guessing. I dont want to toy with it too much more until I begin the repair because I dont want to flex the top enough to increase the separation further and/or cause the brace to pop off.

Is my thinking about the knife/sandpaper to remove the glue, on the right path?

I dont really have a spatula or pallet knife but can get a suitable one if/when I go to the hardware store. Otherwise I see no way to pull the sandpaper from the opposite side of the brace on the inside of the uke...and if fixed to a thin, flat, rigid structure such as the dull knife blade with an adequate handle, I should be able to apply enough little pressure so that going back and forth with it will have enough friction to remove the old, dried, failed glue from both the brace and the top.

If the knife or spatula blade is too wide, which I will test first, I have a metal 'knibbling' tool that I can use to cut it down to fit. The Knibbler takes 4mm square bites out of any metal that is less than about 2mm thick without too much effort, and anything thicker than that, the bits that it bites off will jam it up and I have to take it completely apart to clear it...

Please advise. Thank you kindly.

you could try a nail file or emery board to remove the old glue, if there is enough room to sqeeze it through. Worth a try.

mikeyb2 said:

you could try a nail file or emery board to remove the old glue, if there is enough room to sqeeze it through. Worth a try.

Click to expand...

YES! This is very good idea and simpler than the knife/sandpaper. I will try this first.

Thanks so much for the suggestion. :bowdown:

Booli said:

To sand off the old glue, I'm thinking to use a short-handled old butter-knife (one without teeth of course), bent at a slight angle, and put an adhesive strip of sandpaper on one, or both sides and get in under the separation. If I press down on the top a bit, the brace opens up maybe 2-3mm at the tip of the brace and maybe 1mm where the glue is still solid (kind of like a right-triangle), and this opening is about 20mm long in total, but all measurements are just by eye and guessing. I dont want to toy with it too much more until I begin the repair because I dont want to flex the top enough to increase the separation further and/or cause the brace to pop off.
Please advise. Thank you kindly.

Click to expand...

I didn't realize that the gap was that big so a knife might work. An artist's pallete knife would be thinner though.

Booli said:

Thanks for the suggestions, I'll look into them.

How would one be able to rotate the turnbuckle? I can barely get 2 fingers inside deep enough to reach the area needing repair. 'Ship in a bottle' problems here.


To make my own clamps, I will have to buy even more tools just to craft them in the first place. Right now, I'd rather focus specifically on tools that are directly used to repair the brace. Maybe the local hardware store has clamps with shorter reach? I will check tomorrow.

Click to expand...

The turnbuckle would be like an adjustable stick initially, wedging it tight then doing the impossible turns using long neck pliers or an allen key, bent end then straight end to get quarter turn on.
The cam clamps can be made with very few tools. Even simpler would be a fixed wedge clamp. Make a fixed u shape, a couple of opposing wedges on the top to do the clamping.

These are the clamps I'm talking about

http://www.stewmac.com/Luthier_Tools/Types_of_Tools/Clamps/Soundhole_Clamps.html

Ken Franklin said:

I didn't realize that the gap was that big so a knife might work. An artist's pallete knife would be thinner though.

Click to expand...

Titchtheclown said:

The turnbuckle would be like an adjustable stick initially, wedging it tight then doing the impossible turns using long neck pliers or an allen key, bent end then straight end to get quarter turn on.
The cam clamps can be made with very few tools. Even simpler would be a fixed wedge clamp. Make a fixed u shape, a couple of opposing wedges on the top to do the clamping.

Click to expand...

Allen said:

These are the clamps I'm talking about

http://www.stewmac.com/Luthier_Tools/Types_of_Tools/Clamps/Soundhole_Clamps.html

Click to expand...

Thank you all for the followup.

It may not be until this weekend that I can get to the hardware store and see what is available as per suggestions given so far.

I will report back once I have made the trip.

In the meantime, any other ideas, however 'outside the box' or unconventional, are still welcome.

Once again, thank you very much for taking the time and to offer your expertise to help me with this project.

Here is a 3" C clamp I modified with a fiber metal cutting blade in my skill saw. The other is a half inch ridged tubing with a slot cut in it to hold a slightly longer piece than the interior dimension top to bottom. I push the tubing through the end-jack hole and install the wooden piece through the sound hole then position the piece where I want it and hand twist till it locks in place. Both cheap and simple.

View attachment 97282
View attachment 97281

Is there a way to remove either the top or back without too much damage (or is that just too ridiculous?) forgive me if it is, I'm not a luthier but I have in the past removed a fretboard with heat and not too much damage.

Spokeshave said:

Is there a way to remove either the top or back without too much damage (or is that just too ridiculous?) forgive me if it is, I'm not a luthier but I have in the past removed a fretboard with heat and not too much damage.

Click to expand...

Thanks for the suggestions.

However, I would like to avoid any dis-assembly and re-assembly of the instrument since those efforts are going to exponentially increase the labor, complexity and cost of what could be a much simpler first-time repair effort.

spongeuke said:

Here is a 3" C clamp I modified with a fiber metal cutting blade in my skill saw. The other is a half inch ridged tubing with a slot cut in it to hold a slightly longer piece than the interior dimension top to bottom. I push the tubing through the end-jack hole and install the wooden piece through the sound hole then position the piece where I want it and hand twist till it locks in place. Both cheap and simple.

View attachment 97282
View attachment 97281

Click to expand...

Thanks for these. They definitely appeal to me, and seem like they would be quite effective for this repair task.

I will think on this.

Yeah, removing the top or back is pretty serious surgery and comes with all sorts of potential and actual damage. It is what I would call a "gumption trap". If you don't know what a gumption trap is, start taking the top off an ukulele. Better to get in there with clamps if you can.

sequoia said:

Yeah, removing the top or back is pretty serious surgery and comes with all sorts of potential and actual damage. It is what I would call a "gumption trap". If you don't know what a gumption trap is, start taking the top off an ukulele. Better to get in there with clamps if you can.

Click to expand...

Thanks for the confirmation on my thinking process and for taking the time to reply. I very much appreciate it.