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  #1  
Old 04-08-2015, 02:55 PM
tracedef tracedef is offline
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Default Martin Tenor 2 Uke Total Glue Failure

Hiya,

Posted previously about binding coming off the top / bottom and front / back of waist on 4 year old Martin Tenor 2 Uke (http://www.acousticguitarforum.com/f...d.php?t=381578)

Just noticed that the bridge is coming off as well, this uke was in mint shape when I purchased it 2 years ago and it is a 2011 Model .... not original owner, so no warranty ..... I haven't read about other failures like these but was wondering if the obvious suspect might be humidity as I live a few blocks from the beach??? Have 7 or so other guitars (3 acoustic) but no similar issues among any of them ..... the oldest and most prone to issues being a 1964 Gretsch 6120 ....

Any thoughts on possible cause of glue issues???

















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Old 04-08-2015, 03:23 PM
charles Tauber charles Tauber is offline
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Very good photos.

I'm not sure from the photos whether we see top wood being lifted and attached to the underside of the bridge or if they are strands of glue. I suspect the latter. Usually one sees the latter as a result of heat, though I've seen that occur with Titebond's liquid hide glue at normal summer temperatures and humidities.

I must say that I am surprised by the bridge design. The segmented section of the tie block might have contributed to the issue, causing stress concentrations at the glue juncture. The distortion of the bridge certainly can be attributed to the design.

The good news is that it will be easy to remove the existing bridge. I'd suggest replacing it with one of better design. Not a particularly expensive repair, though I don't know what you paid for the instrument or its value.
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Old 04-08-2015, 03:47 PM
tracedef tracedef is offline
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Charles: Thanks for the feedback. These list for $1749 ... paid around $800 ish .... near mint condition at the time with a single headstock ding. Definitely hasn't been left in a car or any other high heat scenario, so I'm at a loss .... I suspect the quality of Martin Ukes are not on par with similarly priced Martin Guitars, but that is pure speculation ...

The only outlier I can think of outside of beachside moisture in the air is using a Low G vs High G string, so essentially a bigger G string ... but the bridge pull isn't concentrated on the Low G side ... but who knows if that bigger string has any effect overall ....

Thanks for the feedback!
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Old 04-08-2015, 10:27 PM
Frank Ford Frank Ford is offline
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Whenever I see strings of stretchy glue under loose bridges like this one, I presume the cause was heat exposure rather than high humidity. Same for the loose binding, where the shrinkage of plastic material makes for a lot of tension and stress in the waist area of the instrument and the binding pulls away cleanly. No coincidence that whenever binding comes loose, it starts in that region.

Most of the time, the best results are obtained by removing the bridge for cleanup and regluing. Binding removal will release the tension and allow for gluing with aliphatic resin glue, and relatively neat cleanup.
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Frank Ford

Last edited by Frank Ford; 04-09-2015 at 12:02 AM.
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Old 04-09-2015, 10:41 AM
tracedef tracedef is offline
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Thank you Frank! Charles also mentioned heat, but I was thinking of an extreme situation like an instrument being left in a hot car ..... which hasn't occurred with this uke .... but what has happened is lots of playing on the beach ... in the sun. Not at super high temps, usually 65 and a breeze, but it looks like sustained sun exposure is making the most sense .... something I hadn't considered before, but makes sense given the symptoms.

When I'm not playing, I place the uke strings / face down on my towel, as opposed to lieing on its back so the tuners don't touch the towel and it doesn't go out of tune, something I would not do with a guitar ..... so the bridge is only exposed to the sun when I'm actually playing, but apparently my playing time has been enough exposure .....

At this point it looks like I will get the bridge reglued and wait to see how much more binding shrinks ....

Thanks so much for your feedback, I feel confident that I know what is going on now and that the issue is sun and not moisture!
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Old 04-13-2015, 09:08 AM
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Quote:
Originally Posted by tracedef View Post
...When I'm not playing, I place the uke strings / face down on my towel, as opposed to lieing on its back so the tuners don't touch the towel and it doesn't go out of tune, something I would not do with a guitar ..... so the bridge is only exposed to the sun when I'm actually playing, but apparently my playing time has been enough exposure .....
Laying it face down doesn't protect the top and bridge from heat. If the back and sides are exposed to direct sun, the air inside the body is going to get very hot. Think about how warm a car feels inside, even on a cool day, when parked in direct sunlight. I know it's not directly analogous, but that instrument is more delicate than a car too.

Long way of saying I think you found the source of the problem. I'd say after you get it fixed, put it back in the case on the beach and throw light colored towel over that.
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