Quiestions about repair of long neck soprano

Henning

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Hello, my intention is to repair this long neck spruce top soprano on a hobby level. My idea would be to start with the back then put the pieces of the top together.
For the back I would like to use some white glue or titebond and for the top hideglue(?).
My question: is there a risk to introduce tensions in the top if gluing the back first?
Do you have any general advices for the matter of repairing this instrument?
I believe there might be somewhat troublesome to the get the surfaces of the back together in level, as well as cleating it, even though the (now) big soundhole makes the back more reachable.
Regards

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Your approach to this repair is perfectly practical. It makes sense to use the hole in the front for access when repairing the back. I would not be concerned about creating unwanted tension.

As far as I can tell from the photos, there are two long, fairly tight cracks in the back. These should respond well to being glued and cleated. Any broken braces would best be replaced, rather that trying to glue them.

If you have the original pieces for the hole in the front, that should not be too difficult to restore. If not, or if there are several small pieces, it might be better to cut a neater shaped hole and insert a patch of new (very similar) wood.

Best of luck. It looks like an interesting project.

John Colter.
 
Thanks John for your response and encorouging words.
Yes, I do have the parts that are ´missing´ in the top.
Thanks for mentioning about the change of the broken braces I do still have them.
As far as I can see there is just one brace that is loose and off.
 
If it's the two back braces that are still secure, that makes it much easier. The brace beneath the damaged area on the front will be quite easy to replace.

John Colter
 
The back doesn´t have any bracing at all. The bracing of the top consists of three braces in a Classic fan pattern (in parallell to the grain. Fan bracing in a soprano ukulele?!). There are furthermore two square braces. One is above the hole (towards the head). The other is the on that is loose and broken, that is supposed to be below the soundhole (i.e. closer to the bridge). There is also a bridge plate.

I fear damaging the crack in the top while doing the work. It is so (too) easy to touch it. There is already a splnt that sticks out strangely.

Does anybody have any hints for how to get the cracks in the back together nicely?
To align the mating surfaces to a joint that is as good as it can get is an art so the glued crack doesn´t show too much.

Oh by the way, does anybody know anything about these kind of ukuleles I´d be pleased to know. It is a Chinese brand Pearl River Model U-10.

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Does anybody have any hints for how to get the cracks in the back together nicely?
To align the mating surfaces to a joint that is as good as it can get is an art so the glued crack doesn´t show too much.

.

Magnets. There are lots of thin, round and strong magnets available (Ebay for example). Several are placed on the inside along the crack, with another magnet opposite each one on the outside. If the crack needs pulling together horizontally then tape should be sufficient. When everything is correctly aligned feed in the glue.

If it was me I wouldn't attempt to patch up the top, I'd replace it-but then its something I've done several times and may not be worth the effort in this case!
 
Yesterday I talked to a violin maker, he pointed out that it will be easier to repair both the top and the back if either was loose. How could the back be removed?
The reason for this is that it makes it easier to set in the missing pieces in the top and repair the cracks in the back too, as well as gluing the broken bracing of the top.

Best regards
 
Yesterday I talked to a violin maker, he pointed out that it will be easier to repair both the top and the back if either was loose. How could the back be removed?
The reason for this is that it makes it easier to set in the missing pieces in the top and repair the cracks in the back too, as well as gluing the broken bracing of the top.

Best regards

Four days and no answer. It's a tough thing to safely take off the back. I would not take the top off.
If it were myself, I would use a hair dryer in a small section of the back at the joint, with a putty knife in the joint, inside, from the sound hole. Get that part separated from the side and keep going until it's off.
Sorry, I'm no expert. It's what I would do in your circumstances.
After that's done, the top should be easily repaired.
The bottom may take a bit of expertise to get flat, the guys here know a lot more about that than me, I'm just a rank amateur hack!
 
Looking at the damage to the sound board and that being the most important part of the instrument, I would replace it. It is already seriously compromised so aggressive removal can be used. Preparing a new top may be a new adventure for you, ask for help along the way.
 
Looking at the damage to the sound board and that being the most important part of the instrument, I would replace it. It is already seriously compromised so aggressive removal can be used. Preparing a new top may be a new adventure for you, ask for help along the way.

I understand what you're saying. The approach might be too much for the OP, i.e.:

...removing the fretboard, and the neck, that seems like a pretty high level repair. The repair *could* be done fairly well if the back were removed though. From my perspective, as an amateur uke repair guy, it's a safer approach to remove the back and repair the top in situ with CA glue and call it a day. The back will need to come off anyway since it's got braces and surfaces which need attention. Just my 2 cents...anyone who actually knows what they're doing is welcome to correct me! :)
 
In the original post, Henning stated that the intention was to carry out the repair "on a hobby level". Now, because a violin repairer has suggested removing the back, the discussion has moved on to this possibility.

I would consider that removing the back (or the front) goes well beyond the hobby level. It might seem easy, to violin repairers, but they are mostly working with instruments held together with glues made from animal carcasses. These are much easier to dismantle than are more modern types of glue.

I have taken the top off a modern, factory made ukulele - it was difficult and potentially destructive!

An effective and satisfactory repair can be done in the manner suggested in the first few replies.

John Colter.
 
I would think it would be a yellow aliphatic resin glue (Titebond equivalent). And John is absolutely correct, do not take the advice of violin repair people. Violins are put together with hot hide glue and are meant to be disassembled. Even then before you remove the top or back, the sides need to be stabilized in a mold to keep things from moving. If you were to remove the back, the sides will probably shift slightly and you will have fits trying to get everything back in alignment.
Brad
 
I would think it would be a yellow aliphatic resin glue (Titebond equivalent). And John is absolutely correct, do not take the advice of violin repair people. Violins are put together with hot hide glue and are meant to be disassembled. Even then before you remove the top or back, the sides need to be stabilized in a mold to keep things from moving. If you were to remove the back, the sides will probably shift slightly and you will have fits trying to get everything back in alignment.
Brad

If so, it would present problematic issues, IMO. If the instrument is in tension in multiple vectors it will make it impossible to eliminate undesirable resonances all over the tonal range.
 
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