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Dear luthiers.
My friend brought classical acoustic guitar with partly unglued neck and back. Can you please describe the algorithm of repair (my major activity is electric guitars so the problem is not familiar to me). I attached photos. Hope the problem is clear.
Thanks in advance
http://imageshack.us/g/84/p1010028jo.jpg/

I tried new photos
http://imageshack.us/photo/my-images/83 ... 033pn.jpg/
http://imageshack.us/photo/my-images/819/p1010034h.jpg/
http://imageshack.us/photo/my-images/64/p1010035ks.jpg/
There are two cracks: between back and heel and between heel and body side. The tension of strings changed the shape of body side thus it cannot be put exactly on the edge of the back, it extends beyond the back boundaries.
I don’t want to pass this guitar to someone because I want to learn
I try to find someone in my area but it’s quite a problem, because we don’t have associations, seminars about guitar building and repair. Unfortunately.
Hope to get any advice from here.

Could you post some pictures of the inside of the guitar looking towards the neck. My suspicion is that this is an inexpensive "classical" guitar most likely made of plywood and that the neck was butt jointed or possibly doweled to the body. The problem is related to having enough structure to withstand the force of the strings. You could try using a hot knife or heating a thin scraper to remove the back and then replace or re-glue the neck block.

Yes, this is a cheap guitar, that’s why I would like to practice such type of repair.
Here I tried to make photos from inside.

http://imageshack.us/photo/my-images/31/p1010039ri.jpg/
http://imageshack.us/photo/my-images/33/p1010042a.jpg/

As far as I understand in ANY case I should put off the back. Right?

I wouldn't pull the back off unless you have no other choice.... They can be very hard to get lined back up when you try to put them back on.... Especially on cheap instruments where there may not be much lining....

Here's where I would start... Try to determine whether you have a Spanish heel or a glued butt joint neck.... Take a thin metal feeler gage and try to slide it between the neck and body... If it slides all the way from one side of the neck to the other side of the neck in places and only hits in specific places - it is likely a dowel pinned butt joint held together by white glue or hot glue.... Very cheap construction and does not hold up to more than 30-40 hours of use.....

In this case - you can separate the fretboard from the top and then steam the remaining neck joint glue loose.. Pull the neck right off the body.... Once you fit the neck joint back together with new dowels - you can add a bolt through the head block and a threaded insert in the neck heel so it doesn't separate again.... Unfortunately, there's usually too much glue in the joint for a bolt to pull it back together without taking it apart and cleaning it back up....

With the neck off - it's usually not that hard to line the back up and glue the loose parts back together properly....

Of course, while you have the neck off - you could try re-topping the instrument if it's yours.... Make up a nice spruce or cedar top with a more typical "Classical" bracing pattern.... I did it once for the fun of it.... The guitar sounded quite a bit better... Very loud, but quite plain from the plywood back and sides....

Thanks

If you really want to learn. I did that with my Gibson and I'm not sorry at all. I got in there and shaved braces and I had to learn how to put it back together. This guitar came out sounding 100% better than it had before the surgery and it no longer sits in a closet. Maybe I got lucky but like you, I wanted to learn. Of course these lessons shouldn't be learned on vintage instruments but I had already messed this one up long before it was vintage.

_________________
Hutch

Get the heck off the couch and go build a guitar!!!!

I made what you have advised – it’s definitely dowel joint (metal feeler gage slides with no effort and only encounters in certain points with dowels)



Can you please describe how to separate the fretboard from top (it is glued directly to the top)



Re-topping is another project. Thanks for advises!



I would be glad to finish the task without back separation, if it is not possible I’ll try to follow your steps (however if my guitar were vintage Gibson I wouldn’t mange to repair it by myself)

The fretboard is usually glued to the body of the instrument with either wood glue or white glue.... Heat and moisture and a pallet knife will work it loose fairly easily....

I am pretty sure there are tutorials for un-gluing fretboards....

The quick and dirty way is to just make a cardboard protector for the top - with a cutout around the fretboard... Then, heat up the fretboard extension with a clothes iron... Use a pallet knife and a little water to gently coax the fretboard loose....

Thanks