First ukulele cracked under string tenstion! Help!

rpeters · Dec 2, 2012

Hi Everyone,

I just finished building my first ukulele and man does it ever have its flaws! It was a great learning experience and hopefully my future ukuleles will turn out better. My problem however is that the top cracked when I tried to string it up. This is probably because I either made the top too thin or braced it poorly or both. It doesn't look like its going to continue to crack all the way through since it stops at the bridge.

My question is: Is it possible to make this instrument playable without making the crack worst or even fix the crack? What do you suggest I do? This is a gift for my sister and her husband for their wedding and it would be nice if it actually was playable, but it would also look nice just hanging on a wall. Here are the pictures.

BlackBearUkes · Dec 2, 2012

You might be able to add a sliver of wood into the crack and finish over the repair. It doesn't look like you are just going to be able to squeeze it back together. If possible, and you have the long C clamps, you could also just add some repair diamond patch on the inside and call it good.

After looking at the photos of your uke, the bridge position looks to be wrong. Maybe its just the photos, but could you tell me the distance from the nut to the 12th fret, and also the distance from the 12th fret to the bridge saddle?

BR Ukuleles · Dec 2, 2012

Did you build with in a place with stable relative humidity? Looks like a crack cause by too low a RH for an instrument that was built at a higher RH. I would try the sliver of wood method mentioned above. Good luck.

anthonyg · Dec 2, 2012

BlackBearUkes said:
You might be able to add a sliver of wood into the crack and finish over the repair. It doesn't look like you are just going to be able to squeeze it back together. If possible, and you have the long C clamps, you could also just add some repair diamond patch on the inside and call it good.

After looking at the photos of your uke, the bridge position looks to be wrong. Maybe its just the photos, but could you tell me the distance from the nut to the 12th fret, and also the distance from the 12th fret to the bridge saddle?

I thought the same thing although its not really up to me to say it. The saddle LOOKS to be set too long on the body.

Anthony

rpeters · Dec 2, 2012

anthonyg said:
I thought the same thing although its not really up to me to say it. The saddle LOOKS to be set too long on the body.

Anthony

Thanks for the replies everyone! I will try the sliver of wood method. The reason the bridge looks off is because the entire ukulele body is an inch smaller then it was supposed to be. I forget the measurement but the nut to the 12th is indeed the distance from the 12th to the saddle. On a normal sized body it would be about an inch higher. This was because of a terrible mold I used. its one of the many flaws I've had to deal with.

Pondoro · Dec 2, 2012

rpeters said:
the entire ukulele body is an inch smaller then it was supposed to be.

This is not a "flaw", you have built a "travel uke"

rpeters · Dec 3, 2012

Pondoro said:
This is not a "flaw", you have built a "travel uke"

Very true and a good way to look at it. I used a soprano neck from mainland ukulele, but the next one I'll be making my own neck and fret board which will allow me to customize it more to the body of the instrument. I'm curious to see how this thing sounds.

Kurtski · Dec 3, 2012

it may be an optical illusion but I see that theneck joins the body at the 12th fret. The bridge appears to be quite south of where an equal distance would put it. Ii used a caliper to compare the distances. I think the crack is the lesser of the issues.

ksquine · Dec 3, 2012

That's an interesting place for a crack. That bridge is so close to the tail block that there can't be much other top flex to cause a crack.
It looks like the crack might line up with the edge of the tail block....that would suggest a humidity problem to me. Was it humid when you built it and now its dry??
I think its fixable. If you have space between the bridge patch and the tail block, I would add a small patch to support it.

rpeters · Dec 3, 2012

Kurtski said:
it may be an optical illusion but I see that theneck joins the body at the 12th fret. The bridge appears to be quite south of where an equal distance would put it. Ii used a caliper to compare the distances. I think the crack is the lesser of the issues.

It is an optical illusion. The neck I used is a soprano and the body is smaller than a soprano size. The nut to 12 is the exact same distance from the 12 to the saddle. It'll have to do, but the bridge being so close to the tail block may deaden the sound.

rpeters · Dec 3, 2012

ksquine said:
That's an interesting place for a crack. That bridge is so close to the tail block that there can't be much other top flex to cause a crack.
It looks like the crack might line up with the edge of the tail block....that would suggest a humidity problem to me. Was it humid when you built it and now its dry??
I think its fixable. If you have space between the bridge patch and the tail block, I would add a small patch to support it.

Yes the crack is lined up with the edge of the tail block. The body was built in Maine during the humid summer and finished in the Fall. And the instrument is now in New Hampshire where the outside humidity is 62%, but I'll have to see what's like in my apartment with so many heaters drying the place out.

BR Ukuleles · Dec 3, 2012

If I was a gambling man, then you've pretty much summed up the cause of the crack. RH in winter climates and heated homes will dry things out more than most would believe.

rpeters · Dec 3, 2012

Thanks for the help. I'll see if I can fix it and get my hands on a humidifier.

Rick Turner · Dec 4, 2012

What's the tail block made of?
We like 1/2" Baltic birch ply

What direction is the grain running?
It could be that the tail block shrunk pulling the top with it. Too much glue causing swelling and then shrinkage?

Did you bevel the top of the tail block so that the glue line matches the width of the kerfing?
You don't need a large glue area there, and having the glue line a constant width is a good thing in my opinion...

Hot hide glue it...

First ukulele cracked under string tenstion! Help!

rpeters

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BlackBearUkes

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BR Ukuleles

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anthonyg

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rpeters

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rpeters

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Kurtski

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ksquine

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rpeters

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