Fixing a Guitar ?

[Andreus]

Received this broken Nylon 6 string guitar at no cost. If it was a fancy instrument I would not attempt DIY but it's Made in China so I figured I will use it as a learning project.

There is a crack as pictured along the part that joins the neck to the body -- not sure what that is called -- but the fingerboard looks undamaged. I suspect the user may have severely overtightened the strings and fractured it that way?

Does anyone who knows guitars have a tip on how to best fix this?

... Can I just inject glue along the crack and clamp it tight till it sets?

If so what glue would I use? I suspect gorilla glue (my go to) is not appropriate in this context given how it expands.

Or do I need to replace that piece of wood altogether with a new one to join the neck and body ?

Would love to hear tips / ideas / experiences from guitar folks.

 

[Stone Message]

Hi Andreus

I am afraid that the guitar is not designed well if it has come adrift as seen in your pictures. The possible cause may be that the guitar has had steel strings at some stage and its design is not adequate for anything other than nylon or gut.

As an aside just take a look at this inspiring video from about 24 minutes in and see how the neck should be attached:


Back to your problem...

You will need to de-string the guitar and try and break the joint completely. I am assuming that the guitar does not have a truss rod but that will be evident if you see an adjusting nut or screw end.

After breaking the joint you will need to clean off all the old glue and any varnish that may be in the way of a good new glue joint. Somehow you will need to try and match the faces so there are no gaps or voids when brought together.

I am not a glue expert and use mostly PVA but others may be able to give you tips for better glues for this job.

Re-string with nylon and then sell it before it breaks again - it will break again.

Peter

 

[AlexThePalex]

I am afraid that the guitar is not designed well if it has come adrift as seen in your pictures. The possible cause may be that the guitar has had steel strings at some stage and its design is not adequate for anything other than nylon or gut.

This is actually a very common problem with guitars, happened to a €1500 guitar of mine. There's a lot of tension there on a glue joint and failure is always an option, even with quality brands. It does happen a lot faster though with cheap guitars. As for metal strings on a nylon string guitar, you'll sooner pull off the bridge than break the neck joint - ask me how I know  [wink]. 

There is a crack as pictured along the part that joins the neck to the body -- not sure what that is called -- but the fingerboard looks undamaged. I suspect the user may have severely overtightened the strings and fractured it that way?

When you overtighten the strings, they will break long before the neck joint will. Unless the guitar is total crap, which might be the case with yours. Is it even worth the effort?

... Can I just inject glue along the crack and clamp it tight till it sets?

Unfortunately, no, you'll have to do what Peter said above, take it apart entirely, clean all the glue out, and glue it all back again, making sure you'll get the same thickness of glue as before. If you don't do it like this, the neck will be attached at a slight offset in length or angle, and the whole intonation of the guitar is gone, it will be always out of tune.
 

 

[lwoirhaye]