Glue for an Acoustic Bridge?

[Mincer]

OK, this is actually for a Ukulele, a really cheap one, maybe worth total less than $50US. It is also for a 2nd grade music class (they have about 20 ukes in various stages of disrepair, because, well, they are in 2nd grade). Several have the bridges popped off.
I know for a good acoustic guitar, the standard is hide glue. But I wanna make sure these puppies never come off again, so 'ease of future repairs' is not a consideration. Epoxy sometimes works, but in Florida's humidity, it doesn't always cure properly, and eventually soaks into the wood and fails. Wood glue? Super glue (does that even work on wood-to-wood contact?).
I need something strong. Crazy strong. Something I can find easily and cure quickly is preferred. Ideas?

 

[crusty philtrum]

Re: Glue for an Acoustic Bridge?

I glued a new bridge onto a classical guitar a few years back using superglue. I put a couple of heavy telephone directories on top of it and left it for a day, then strung her up. (I had put a double layer of masking tape around where the bridge had to be located, and that kept it from slipping while the glue dried). I have since given the guitar to a friend of mine, but the bridge is still on there, as good as it ever was.

 

[guitfiddle]

Re: Glue for an Acoustic Bridge?

Tite Bond.

 

[David Collins]

Re: Glue for an Acoustic Bridge?

I don't think you really need anything crazy strong for such a job, as they don't really hold that heavy of a load. You just need something convenient and durable under the relative conditions - something moisture resistant and with decent gap-filling strength properties, since I assume you're not going to spend much time fine fitting the bridges to a flawless wood to wood joint.

Either epoxy or superglue would be appropriate for this, epoxy being my first choice. System 3 epoxies cure perfectly fine in high humidity, as do West System epoxies in my experience. General hardware store epoxies may be more prone to curing problems in high humidity, though I don't really have much experience with those. Epoxies like System 3 or West System are not cheap of course, but still can end up cheaper ounce for ounce if you compare to using superglues.

Other moisture resistant glues such as modified PVA's (Titebond II or III) or Polyurethane adhesives (Gorilla Glue) may be moisture resistant, but they have no gap filling strength at all. If the joint is not perfectly mated wood to wood, or if the surfaces are still at all contaminated with remnants of previous glues, I would not choose any of these.

A good epoxy would probably be the most suitable for this application. Cyanoactylates would work okay as well, but be a whole lot messier, and probably end up costing you about as much or more if you're doing more than a just a few bridges.

 

[Bludave]

Re: Glue for an Acoustic Bridge?

OK, this is actually for a Ukulele, a really cheap one, maybe worth total less than $50US. It is also for a 2nd grade music class (they have about 20 ukes in various stages of disrepair, because, well, they are in 2nd grade). Several have the bridges popped off.
I know for a good acoustic guitar, the standard is hide glue. But I wanna make sure these puppies never come off again, so 'ease of future repairs' is not a consideration. Epoxy sometimes works, but in Florida's humidity, it doesn't always cure properly, and eventually soaks into the wood and fails. Wood glue? Super glue (does that even work on wood-to-wood contact?).
I need something strong. Crazy strong. Something I can find easily and cure quickly is preferred. Ideas?

Titebond would be the way to go. But its a catch 22. The reason hide glue was used back in the day is it was cooked and the adhesive would actually bond with the fibers of the wood. The advantage to using hide glue is if the instrument dries out(very typical in Winter) the top sinks into the body & the bridge either cracks at the pins or pops of. Using better glue will stop the bridge from coming off, but if the bridge doesn't come loose, it may cause the top to crack. Consider keeping some moisture available to these in the winter months.

 

[Mincer]

Re: Glue for an Acoustic Bridge?

Right, however, this is Florida, with near 100% humidity every day, winter or summer.

 

[guitfiddle]

Re: Glue for an Acoustic Bridge?

Virginia has some really humid days in late Summer, and a very top notch luthier out there has glued every joint on every guitar he's made (375 or so by now) with Tite Bond. Guitar strings pull way harder than a Uke, so I think you'll be ok if you do the prep on the wood like Bluedave says.