Crack repair advice

gyosh · Mar 20, 2012

Hi all,

I have an unfinished uke that has a surface crack from the base almost to the bridge. It doesn't seem to go all the way through the wood and it doesn't close up any, with moderate pressure on each side of the crack. I'm wondering if I can go ahead and finish the uke with Tru Oil and take care of the crack sometime in the future or should this be addressed before I apply oil?

Not sure if this information will help, but before I sanded that area, the wood was kind of "wash board" like in that section.

Thank you for your help,

-Gary

Pukulele Pete · Mar 20, 2012

I'm no expert but I would fix the crack first. The oil might stop your glue from bonding correctly.

BR Ukuleles · Mar 20, 2012

Without any question at all. Fix the crack first!

If you get oil in it, you'll never fix it without cutting out a sliver and replacing a piece of the top. As it stands right now, you may have to slip a sliver of wood into the crack even now, but it'll still be easier without finish on it.

I'd be using hide glue for a repair like that. PVA's are going to work, but will potentially make a lot more work of clean up. Hide glue is invisible under finish. PVA's will show up like you wouldn't believe if you don't get it cleaned up properly.

gyosh · Mar 20, 2012

Allen said:
Without any question at all. Fix the crack first!

If you get oil in it, you'll never fix it without cutting out a sliver and replacing a piece of the top. As it stands right now, you may have to slip a sliver of wood into the crack even now, but it'll still be easier without finish on it.

I'd be using hide glue for a repair like that. PVA's are going to work, but will potentially make a lot more work of clean up. Hide glue is invisible under finish. PVA's will show up like you wouldn't believe if you don't get it cleaned up properly.

Thank you for the reply Allen. It's actually the uke I built in Rick's class this past October. It cracked about three weeks after the class and I never got around to applying the finish. I've been playing it that way the whole time. The crack hasn't gotten worse so I wasn't really that concerned, but now I want to bring it to the Roy Sakuma Uke Festival in July so I was going to finally apply a finish. I honestly can't imagine putting a sliver in there unless you made it bigger first. You luthiers are truly amazing! Again, thank you for taking the time to reply.

-Gary

BaldEagle5556 · Mar 20, 2012

I am far from an expert but I recently repaired a couple of cracks in my son's classical (beater) guitar. I used hot hide glue, put it on the crack and percussed the crack (bang on it with your finger rapidly to get the glue into the joint - learned this from a youtube video where a luthier repaired a ukulele top). The set time is quick on hide glue so one trick is to heat the wood with a hair dryer before applying the glue. When it starts to gel or set a wet paper towel cleans up the excess glue.

This is the first time I have used hide glue and I will use it more now.

I also agree with fixing the crack before finishing.

Tom

gyosh · Mar 21, 2012

BaldEagle5556 said:
I am far from an expert but I recently repaired a couple of cracks in my son's classical (beater) guitar. I used hot hide glue, put it on the crack and percussed the crack (bang on it with your finger rapidly to get the glue into the joint - learned this from a youtube video where a luthier repaired a ukulele top). The set time is quick on hide glue so one trick is to heat the wood with a hair dryer before applying the glue. When it starts to gel or set a wet paper towel cleans up the excess glue.

This is the first time I have used hide glue and I will use it more now.

I also agree with fixing the crack before finishing.

Tom

So no clamping or cleats? You basically just filled the cracks with glue? How is it holding up?

BaldEagle5556 · Mar 21, 2012

I did clamp it for about 4 hours ...sorry I omitted that.

Tom

Tarhead · Mar 21, 2012

If you have not kept it in a humidity controlled environment you may want to bring the humidity near to the level it was built for a week or so. I assume Rick has control of this and shoots for the 40-50% range. The crack will come together like magic greatly simplifing the repair. Rub glue into the crack while you push up slightly on the crack from the inside. Store it in its case with a humidifier after it is repaired.

Crack repair advice

gyosh

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