Kasha bridge lifted at rear

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Quinny
Myrtle
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Kasha bridge lifted at rear

Post by Quinny » Sat Aug 04, 2018 5:13 pm

Hi there,

I made a tenor uke 3 years ago, but not played much. However, the kasha bridge has lifted at the back - see image below. When I release the tension on the strings the bridge doesn't settle back down to narrow the gap to the soundboard. So I assume the glue bond is holding, or the pins are holding it in place??

The bridge is Cocobolo (Mexican rosewood) and the soundboard Myrtlewood. I am not sure if I used PVC or epoxy glue. I realise the high oil content of Cocobolo might the a problem if I used PVC.

My queries if you can help:
- Should I fill the gap with epoxy or something else to strengthen it in its current lifted position?
- Do bridge pins on such a small bridge (compared to a guitar) weaken the bond by drilling though the top board or reducing surface area for the bond at the rear of the bridge?
- Is epoxy just as good for gluing bridges as PVC, or better? I guess I thought PVC has more give in it, which may be a desirable attribute, but an assumption on my behalf.

Any ideas appreciated.

Thanks
Quinny
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kasha bridge lifted.jpg

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kiwigeo
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Re: Kasha bridge lifted at rear

Post by kiwigeo » Sat Aug 04, 2018 5:55 pm

Looks to me like the bridge pins are all that is stopping that bridge flying off the uke. If it was me I'd lift the bridge and re-glue it. Is the top flat or is there a bit of curvature? Before re-gluing the bridge check that the underside of the bridge fits snuggly against the top without any visible gaps. If concerned about the oil content of the bridge wood then wipe the underside with meths or acetone prior to gluing.

Re glues - epoxy will work but any repairs further down the track will be a nightmare....it's best restricted to joints that either require a glue free of water (eg fretboard-neck) or it's a joint that has a low chance of needing repair some time in the future. AR (Titebond) glue is fine for a bridge on a uke. Hide glue has a higher sheer strength than AR so is probably the best glue to use where there is sheer stress on the joint. In your case Titebond is the best choice.
Martin

Quinny
Myrtle
Posts: 74
Joined: Mon Oct 06, 2014 1:16 pm
Location: Box Hill, Melb

Re: Kasha bridge lifted at rear

Post by Quinny » Sat Aug 04, 2018 7:50 pm

Thanks kiwigeo. I think I do need to re-glue the bridge - I can now see from the photo that the bridge pins are what is probably holding the bridge in place. I will check the top is not curved, but that wasn't in my build so I hope it isn't.

Re your comment on glues for bridges - If i used PVC i only use Titebond. So all good there!

What is your opinion on using bridge pins on ukes in terms of reducing the surface area of gluing for the back area of the bridge,. In other words, it is not advisable???

Ta heaps

quinny

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kiwigeo
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Re: Kasha bridge lifted at rear

Post by kiwigeo » Sat Aug 04, 2018 8:41 pm

Quinny wrote:
Sat Aug 04, 2018 7:50 pm
What is your opinion on using bridge pins on ukes in terms of reducing the surface area of gluing for the back area of the bridge,. In other words, it is not advisable???

Ta heaps

quinny
I've never had issues with bridge pins interfering with integrity of the bridge/top glue joint.....if it is of concern then you can always add a bit of meat to the rear of your bridge aft of the pin holes.

If the top isn't flat then its a good idea to work the underside of the bridge to fit the shape of the top. I do this by fixing some sandpaper to the bridge area of the top with double sided tape and working the bridge over the sand paper. There shouldn't be any gap underneath the bridge when its sitting on the top.
Martin

Quinny
Myrtle
Posts: 74
Joined: Mon Oct 06, 2014 1:16 pm
Location: Box Hill, Melb

Re: Kasha bridge lifted at rear

Post by Quinny » Sun Aug 05, 2018 5:57 pm

Makes sense. Thanks Martin. Love the tip of sandpaper on the top to match the curve to the bridge underside.

Thanks again

Andrew

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