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Timbuck
12-14-2017, 12:36 AM
This is a little soprano I made a couple of years back..It was part of a batch of experimental uke's I built using the old traditional Island method with the mould on the inside like a violin build...Unfortunately the Guy who bought it had a bit of an accident with it and it got a crack in the top about 130mm long....He sent it back to me to see if I could fix it for him...When it arrived the crack was open about 1mm and would not pull together for gluing...So I put some soggy wet paper towell inside an open plastic bag and placed it inside the uke, covered over the sound hole and left it in the cold workshop for about 10 days to humidify...Today I looked at it again and the crack had closed right up tight so now I'm going to attempt a repair.....I'm using some magnets to hold the sides of the crack level and I'm going to use tight bond to glue it....I don't normally do repairs like this so any advice is welcome...(The wispy bit by the end of bridge is just a bit of fluff that fell on while I was taking the pic :) )
https://farm5.staticflickr.com/4679/27271378849_69cff2e20d_c.jpg (https://flic.kr/p/HxSWP4)PICT0065 (https://flic.kr/p/HxSWP4) by Ken Timms (https://www.flickr.com/photos/150702140@N02/), on Flickr

Graham Greenbag
12-14-2017, 05:08 AM
A lovely looking Uke and I think that’s it great you standing behind your products in repairing this one.

I recall seeing a video recently about someone doing similar using hide glue and tapping the glue into the crack with their finger (percussing I think that they called it). It was glue from a traditional ‘warmed-up’ type glue pot, not something from a tube, so I guess a degree of heat sensitivity is involved. He wiped the excess glue off of the outside with a wet/damp paper towel and then a further dry one. How quick will the glue set? I prefer to work with slower setting glue as it gives time to sort out what don’t fit or is attached to the wrong thing, etc.

Clever that using magnets. I guess that you’re using some thickish sheet metal the other side or maybe a penny washer? No chance of the glue coming through or sticking to the washer / magnet ....... that’s just what would happen to me. I had to reglue a loose strut a couple of weeks back, it was difficult working through the sound hole but I managed an effective repair. A small mirror was a big help and no one will see the excess glue around the (my) joint.

Good luck and please tell us how you get on.

Ukecaster
12-14-2017, 05:29 AM
I'm no tech, but believe that some also use cleats under the soundboard to make sure the glued crack holds.

I had a top crack repaired on a vintage uke a while back. I asked the tech if he added cleats, he said: " No cleats needed. A violin builder I spent 5 years with hated them, and taught me how to repair cracks without them". What that method is, I'm not sure.

Timbuck
12-14-2017, 06:00 AM
I'm no tech, but believe that some also use cleats under the soundboard to make sure the glued crack holds.

I had a top crack repaired on a vintage uke a while back. I asked the tech if he added cleats, he said: " No cleats needed. A violin builder I spent 5 years with hated them, and taught me how to repair cracks without them". What that method is, I'm not sure.

I'll be fitting some thin cleats but not many..and I'll use the magnets again to clamp e'm ...Graham, i use the magnets top and bottom they really grip hard...and you can slide e'm about along the crack.

mikeyb2
12-14-2017, 07:40 AM
Ken, I've not done this myself, but there are a few out there that use thin superglue/ca to wick into the crack. I imagine the crack would have to be well closed up for this to work. It might be easier than trying to get enough Titebond squeezed in there.

Timbuck
12-14-2017, 01:30 PM
You can dilute the Titebond a little with water or spit ;) and rub it well into the crack with the finger end before the magnets go on ...and heavy tapping around the area to allow the glue to penetrate.
..

Pete Howlett
12-14-2017, 02:37 PM
Don't use cleats. Use brown tape -the type you wet to activate the glue. As it dries it shrinks and the organic based glue integrates wit the wood. You'd be hard pressed to get it off without wetting it thoroughly....

Timbuck
12-15-2017, 02:31 AM
Don't use cleats. Use brown tape -the type you wet to activate the glue. As it dries it shrinks and the organic based glue integrates wit the wood. You'd be hard pressed to get it off without wetting it thoroughly....
I have used it on the back of rosettes Pete when I've gone a bit too deep with the channel :rolleyes:.. I've got a roll of it somewhere I'll try and find it.

EDW
12-15-2017, 02:57 AM
I had a top crack repaired on a vintage uke a while back. I asked the tech if he added cleats, he said: " No cleats needed. A violin builder I spent 5 years with hated them, and taught me how to repair cracks without them". What that method is, I'm not sure.

Staple gun?

Ukecaster
12-15-2017, 04:15 AM
Staple gun?

Yeah, but koa staples are hard to find these days

EDW
12-15-2017, 05:38 AM
Actually, it is sad to see some of the "homemade" repairs on some other wise lovely instruments you see online. Too often you see butcher jobs that trash the instrument.

sequoia
12-15-2017, 07:20 PM
This is the type of failure that keeps me up at night. Thinking. If it makes you feel any better Ken, the great Torres and his guitars tended to come apart and split after a couple centuries. The fix was to take paper (music sheets usually), mix a glue of flour and water paste and stick them up underneath to stabilize the situation. It didn't really work. Still some said this added to the sound. Take heart my friend. That a split Torres guitar that is held together with paper, flour and spit sells for about a half million dollars. I am confident in hundred years your instruments will be classics.

Timbuck
12-15-2017, 10:20 PM
The Guy who owned this uke was lucky co's I had another identical one left over from the batch of six that I made...So seeing as it was Christmas and I was in a generous mood (pissed) and the fact that he had purchased several other ukes from me over the years...I replaced it for small fee ;) here is a pic of the crack before I started the repair...It's interesting how the rosette rings did their job to prevent the grain splitting at the soundhole..I lot of folks think the rosette is just decoration.:rolleyes:
https://farm5.staticflickr.com/4646/27306650959_a5675ae945_b.jpg (https://flic.kr/p/HAZHYT)crackpic (https://flic.kr/p/HAZHYT) by Ken Timms (https://www.flickr.com/photos/150702140@N02/), on Flickr

mikeyb2
12-15-2017, 11:06 PM
[QUOTE=Timbuck;2023053]The Guy who owned this uke was lucky co's I had another identical one left over from the batch of six that I made...So seeing as it was Christmas and I was in a generous mood (pissed) and the fact that he had purchased several other ukes from me over the years...I replaced it for small fee ;) here is a pic of the crack before I started the repair...It's interesting how the rosette rings did their job to prevent the grain splitting at the soundhole..I lot of folks think the rosette is just decoration.

Interesting, didn't realise about the rosette. Thanks Ken for pointing that out.

Timbuck
12-16-2017, 02:11 AM
The Guy who owned this uke was lucky co's I had another identical one left over from the batch of six that I made...So seeing as it was Christmas and I was in a generous mood (pissed) and the fact that he had purchased several other ukes from me over the years...I replaced it for small fee ;) here is a pic of the crack before I started the repair...It's interesting how the rosette rings did their job to prevent the grain splitting at the soundhole..I lot of folks think the rosette is just decoration.


Interesting, didn't realise about the rosette. Thanks Ken for pointing that out.

Some builders fit a reinforcement patch under the soundhole, but I think that kills the zing in the top...:2cents:

sequoia
12-16-2017, 06:35 PM
Some builders fit a reinforcement patch under the soundhole, but I think that kills the zing in the top...:2cents:

Good example of a rosette stopping a crack. Those old luthiers knew what they were doing. They were no dummies. It ain't just about bling.... I was loath to put under-top reinforcement around the sound hole even though any woodworker can see the inherent weakness of the design of having a round hole in the middle of a supporting structure. I made some with and some without and much to my surprise it seemed to make no difference to the sound whatsoever. Niether positive or negative which still puzzles me a bit. But then again I'm frequently puzzled... Also from a structural point of view a soprano uke doesn't really need any reinforcement there. Tenor or baritone yes maybe.

Timbuck
12-17-2017, 02:31 AM
Jobs gone pearshaped:(...uke was left overnight in a warm dry room and the crack has pulled apart again:wallbash:
Looks like a new top is required...It's built with hide glue so it wont be too difficult. (He says with confidence)