tail piece buckled 12 string top

[John Anderson]

A friend of mine gave me this espana 12 string. I am by no means a Luthier. I do own a furniture restoration shop so I know my way around a piece of wood fairly well. Any advice on how I might fix this? If it was a 3 drawer dresser I would know just what to do.

[Mike Kolb]

Well, that's original :)  Is there a tailblock in there? If so, did the tailpiece just shove the block out of position?  The damage to the top itself looks worse than it probably is, since all the pieces appear to be there... but the trick will be to get the innards back into position and glued solidly. Once the tailblock is reset and glued, repairing the top is just patience and fussing.

Rummage-around Frank's 'sister-site' (www.frets.com) and there's tons of info on repairing tops. But first thing will be dealing with the block. If it's old and crumbly, it's probably time to construct a new one before anything else.

Good project! Have a ball... 

[John Anderson]

Thanks Mike. I figured the tailblock was the issue. It seems to be about 1 1/2" wide x maybe 1" thick. Thanks to the convenient new flap on the top I can lift it up see the tail block clear as day. Can I replace it without removing the back?

[Kerry Krishna]

You have an excellent good sized hole there to do all the work through John. The trick will be to protect the spruce top broken edges from damage while you are getting the old block out. Is it just me. or does anyone else here think that maybe they did not glue the spruce/endblock interface?

[John Anderson]

The block was firmly glued to the spruce top. I used steam and a razor blade to break that bond and let the top start straightening out. The block is somewhat loose from the side. Steam and a putty knife or chisle? Then duplicate the block slightly larger and glue and clamp it through the top flap then glue the top downn. Maybe use a small brace where the top is broken cross grain? I never have to worry about affecting the tone when I am fixing a night stand. So I am concerned about killing the vibration. So I don't want to over do it. Does this sound like a resonable approach?

[Tim Mace]

Either blunt force trauma or way overtuning or both.....yuck...If I were as wood savvy as you I'd take the top off ,do whatever it needs...

[John Anderson]

I am strongly considering removing the back.  I just don't see how I can really get in there and do the needed repairs any other way.  I've never done that before. We will see if I end up with functional 12 string or a decorative wall hanging and a sad story.

[Tim Mace]

That way 2!

[John Anderson]

Ok, not going so well so far.  Got the binding off without too much trouble.  broke once so it is two pieces.  I scored around the edges of it to prevent damage to the surounding finish and wood.  Got a few chips and lifted splinters.  I can work with that.

I tried to insert a razor blade between the perfling and the guitar bottom and then insert a putty knife to pop the joint.  wouldn't budge.  Added a few drops of hot water.  Still wouldn't budge.  Tried a few drops of rubbing alcholol.  Still no luck.  Tried heating the joint with an iron and a slightly damp cloth.  Nothing I tried had any affect on the joint.  I ended up working a razor blade in the joint and just cutting it off.  Got quite a few splinters at the the tail block.  about 4" inches of the perfling broke loose from the side of the guitar.  The head block is still firmly attached to the back.  I am thinking I need a very thin backless saw to cut the head block away from the back.

 

Anybody have any helpful suggestions or biting reprimands?

[Tim Mace]

pictures.........you mean neckblock?Did you try heating the knife?It will only help if its' hide glue...

good luk

[John Anderson]

Yes I meant neck block. I will try heating the knife. I laid an iron on it with a damp cloth so I got the joint pretty hot. It didn't seem to have any effect.

[Ned Knepp]

The neck block is a heat sink that will probably take more heating than you can safely do with a wet cloth and iron.  Most of us have a very thin pallet knife or a thinned down, rounded putty knife to help with this. I heat mine in hot water and work them into the joints. It's not fast and I have to watch the heat but it (usually) works.  My brother used to use, and I have used in the past, an open flame to heat the knife but I don't do that and don't recommend it. It's very easy to over heat things and mar the wood with a burn.

 

My favorite knife for this is about two inches wide with a bit of a curve  along it's length with a round tip. This curve and round tip helps me keep it from digging into the wood. It has been carefully ground down until it is very thin along most of it's length. It's  not thin enough to fold up under pressure but it is thin enough to be pretty springy.

 

  Don't pry on it or you will probably split the back. I use a couple of other thin instruments, to help me keep the hot, wet glue separated. These can range from more pallet knives to wooden wedges. (Wooden wedges in the areas that are wider and not so sticky.) These apply SOME little bit of pressure but not much. I let the blade do the "cutting".  I work the edge with the seam of the glue and let the moisture and heat do the real work.  I don't like using a sharp edge on the knife because I think it tends to wander around in the grain too easily. My blade is thin but not sharp. Even with that it's pretty easy to wander if you are not careful. 

Depending on the glue, a bit of hot water can help too and since I use hot water as my source of heat it's already supplied.  I don't like a lot, but just enough to keep the interface a bit wet as I work it. 

 

The blocks are always tough. BTW, if you have a plastic heel cap, be careful that you don't melt it. It's usually best to pull it off before you attach the back, if you haven't already done it.