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PostPosted: Thu Jul 03, 2014 5:34 pm 
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Walnut
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This is a brazillian cavaquinho ( "cava -keen-hyo"). a cousin to the ukalele.
Its less than 6 months old but I am 7000 miles away from the warranty.

Image

I noticed that the action was getting higher. Then I noticed that the neck is parting from the body. You will see it is not typical construction. My first thought is to fill the crack with glue and clamp it together. I don't think that I could remove the neck completely but that would be best. Then I could do a complete reset job.

Thoughts?


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PostPosted: Fri Jul 04, 2014 3:49 am 
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Walnut
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Sorry. I was really tired when I wrote this post. It should really have gone into the Ukulele/mandolin forum.


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PostPosted: Fri Jul 04, 2014 8:36 am 
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Naaaa here is fine , if you clamp it back in place does it level back out to where its supposed to be ?

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PostPosted: Fri Jul 04, 2014 9:05 am 
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Walnut
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If you clamp it really hard ..... mostly. My fear is that the wood and the strings will always be trying to pull it apart again, so adjusting it to get the neck set right would be best.
I haven't see a neck joint like this - without a dovetail. I wonder what it is.


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PostPosted: Sat Jul 05, 2014 10:05 am 
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I'm guessing the original construction was with hot hide glue, which may reactivate the dry glue in the joint. It is a joint, yes? Looks like standard "stacked" Spanish heel construction, and that the joint failed where we see the light coming through in the photo.

With some luck, you should be able to get some hot hide glue in there and clamp it tight before the glue cools. If you're not familiar with hot hide glue, I suggest reading up on it. Other wood glue might work, but the chances of success are best with hot hide glue.

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These users thanked the author Frank Ford for the post: Pbassred (Sat Jul 05, 2014 3:12 pm)
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PostPosted: Sat Jul 05, 2014 3:11 pm 
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Walnut
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"stacked Spanish" That is a very useful piece of information. Several youtubes and google later, I'm starting to get the idea. A cheaper neck because its built of several pieces, and its likely to be some kind of shallow mortise & tenon joint. (There are no screws, by the way).
I'm not an experienced luthier but I reckon that the glue is more likely aliphatic. I have been able to remove some of it with a warm knife. Plus the glue on the inside has a yellow look. I just bought some hide glue but I've never used it before.
What concerns me is that I can only see the outside of the joint. The inside is likely to be busted too, but I won't be able to get the old glue out. If I clamp down on the glue it might prevent the neck going down where I need it to be (as far down as possible.) I can see that I need to get creative.


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PostPosted: Sat Jul 05, 2014 5:27 pm 
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Cocobolo
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Do an Internet search for Spanish heel construction. Note I haven't said "Spanish neck joint" because there is NO neck joint in that kind of instrument - the heel is integral with the what looks like a neck block inside. Looking inside, if you see end grain, it's a Spanish neck, if you see a side grain - either vertical or horizontal - it's a neck block construction, with any of a number of different kinds of joints possible. As a general rule, the inside of the Spanish neck construction is not a rectangular section, but more tapered - wide at the top, and narrow at the bottom. It's the traditional method of construction for classical guitars, and common throughout Spain and Latin America, but fading quickly in the face of more modern production techniques.

Regardless, the repair is the same - squish in some glue, clamp it up. 99% of the load will be held by the area beyond the sides, where it's easy to get the glue in there. Medium viscosity cyanoacrylate will hold well, but it can be a royal mess to clean up.

Here's a bit on clamping necks, with a simple rope trick included:

http://www.frets.com/FretsPages/Luthier ... clamp.html

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These users thanked the author Frank Ford for the post (total 2): Pbassred (Sun Jul 06, 2014 3:56 am) • EddieLee (Sat Jul 05, 2014 6:48 pm)
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PostPosted: Sun Jul 06, 2014 4:35 am 
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Walnut
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Ha! really? That's it? a continuous block of wood and a lap joint? Well, the world just became a simpler place. I can clean out that entire joint with wet & dry paper. Possibly induce a neck set at the same time.
You mentioned Cyano. ( oops_sign Did we wake the devil?) I have lots of that but the working time is scary. My adhesive of choice is epoxy because I can select my working time. I was going to go with hide glue because everyone swears by it, but if I am throwing traditional materials to the wind. Its there any reason why epoxy isn't as good as cyano?


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PostPosted: Sun Jul 06, 2014 9:03 am 
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Epoxy can be a good choice, too - it has gap-filling qualities as well, and, depending on the finish, cleanup might be easier. Fact is, there's not time or space here to do a full tutorial. Each adhesive has its own working characteristics, gap filling abilities, strength, etc.

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