A severe neck break

B. Howard

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Here is a Gibson with a severely broken neck. This is actually the third time this guitar has fallen and suffered a broken neck. You would think the owner would have bought a stand considering this is his favorite axe. This guitar was sent in from another shop because the severity of the damage is beyond their comfort range as far as repairs go so I will repair the structural damage and apply a finish to the neck and return it to them for any necessary fret work and final assembly/set up.



Once I remove some of the heavy finish that was applied we can see some of the previous repair work. This included a set of splines. They appear to have been part of the first repair.



One of the first things I do in these situations is conduct a forensic analysis and map out all of the cracks and breaks, including those that were repaired previously and have held. This shows me exactly what I am working with and around. It also shows me how the previous repairs held up and allows me to learn how to make better repairs. The first break appears to have been the classic one right at the heel making the famous Gibson smile. This appears to have been when the splines were inserted as while it is not marked in this photo I noticed later as I was cleaning and prepping to glue up that the second set of breaks actually went through the Maple splines. I personally would not have put any splines in a simple break such as the first one appeared to be.





There was very little in the way of wood fibers holding this all together. And the only way forward in some of these situations is to complete the break. The shaft of the neck was also pretty badly shattered about 3”- 4” down from the end of the splines. This also involved the truss rod pocket to a large extent





I would like to give my thoughts on splines in neck repairs in general and this repair specifically. To every point there is a counterpoint and at the risk of ruffling some feathers, which is truly not my intent, I would like to present some of the counterpoints to these type repairs. If you look at the previous two photos you should notice the white lines I have marked down the shaft very much in line with the pockets for the splines. These happened in the second break. Any time splines are used the risk of a splitting fracture like this becomes a real likelihood in the event of another mishap. This is helped in part by the fact that the truss rod channel also runs down the center of the neck, leaving very little in the way of continuous long grain wood fiber through the neck.

In our case here it was exacerbated by the fact that we have maple splines in a mahogany neck. I’m sure the thought was it would be stronger. This extra strength gave the splines a bit more leverage during impact and their added strength actually transferred the force of the fall up the neck. The splitting was also aided by the fact Maple and Mahogany have very different expansion rates and characteristics with regards to moisture content and relative humidity. This means that the pieces did not move in sync with each other and placed stress on the glue joints of the splines. Maple actually shows greater expansion relative to MC than Mahogany (although it reacts much slower) which means that at certain times the maple may have been so tight in the pocket that it actually acted as a wedge and may have even started to crack the neck before the second fall. The new breaks running down the shaft of the neck also generate from the spline pockets, both the ends and the bottom.

Another problem here was that the spline on the treble side was not completely seated in its groove as we can see in the next photos. It became hydro-locked by glue. This left only the tiniest sliver of wood running up the edge of the neck holding that side of the fretboard. This could have been because the fit was too tight or just a plain excess of glue. Either way it left a section of fretboard unsupported right at the very end. Something else that I don’t like while it hasn't been an issue yet is that the top of the splines ends directly in line with the E tuner holes. Again, minimizing the amount of long grain fiber actually running through the area and weakening it. If it falls again that is where I expect it to break.




Don’t get me wrong, splined repairs have their time and place. They make very good repairs if done correctly. They should only be used in severe breaks where there is not enough long grain to successfully glue up. They should always be done with the same wood as the surrounding neck. Thinner is better than wider as this keeps them farther in from the edge and farther away from the truss rod pocket. They should only be as long as necessary to bridge the damage. Consider staggering the ends to lessen the chance of a new break happening at the ends in the future. Make sure they fit completely with no voids and use only enough glue to do the job.

This neck is far beyond any type of splined repair. While I do not like the maple splines, at this time I see no method of redoing them and staying within the customer’s budget. So it is time for some structural epoxy. This has actually become my go to repair for anything beyond a simple break. The first thing I do is start dry fitting the pieces back together and looking for out of place fibers that are keeping it from closing up. These are either pushed back in place or removed with dental picks and an exacto. Due to all the splits running down the neck I will be using a compression wrap to force epoxy into them. I will then apply clamps as needed over top of this as well. This is all tested dry a few times with some measurements being taken along the way to check alignment until I am satisfied with the procedure and the results.

First I cover the threads on the truss rod with some wax so they don’t get epoxy on them being very careful not to get any wax on the wood as it would weaken the joint. I tape off the fret board and peg head face. I then mix up a few grams of epoxy. I use System 3’s T-88. I wedge open any cracks in the neck that I can and let the epoxy run into them for a few minutes. I coat the entire open surface and work epoxy into all the joints I can. I slip the neck back together over the truss rod and then wipe a medium coat of epoxy over the entire area. This is wrapped in a double layer of wax paper and then wrapped with rubber straps pulled tight. This forms a bit of compression and helps drive the epoxy into the cracks. Clamps are then added to pull the neck together lengthwise and apply a bit of extra pressure on the end of the fret board. The epoxy is left to cure for 24 hours and this is what we have when it is unwrapped.



With a bit of scraping and sanding it looks like a neck again. It needed a little bit of filler in a few spots to even things out but here it is wet with solvent being inspected prior to finishing.



And here it is with finish applied. The rest of the neck was pretty beat and had some dings and gouges including a large spot from where he leans it against his amp. All these were filled as well and the whole neck finished in a dark opaque brown to blend in with the outer portion of the burst finish on the body.

 

xroadie_jim

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Great forensic analysis write up and solution. Thanks for the post.
 

Fret Hopper

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And this is why masters like BHoward, BCRGreg, and others cannot quote a neck break repair without personally inspecting the damage. You just don't know what you are dealing with until you really dive into it.

From the ozone...

Mark
 

Skyjerk

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Holy Crap. Its amazing you can take such an utter wreck and make it so beautiful again.

the owner must be some kind of...oh never mind
 

GrouchyDog

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Wow, nice rescue. Thanks for posting this, I love repair threads.
 

Otto tune

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Wow! I'm surprised you didn't find termites in that mess.

Speaking of epoxy, has anyone tried the West system boats used to use? I understand it's very thin and flows into the fibers.
 

emoney

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Wow Brian, this is an awesome thread and you did a marvelous job repairing this one.
I simply can't believe that last pic is the same neck. Kudos AND hats-off, how's that for a
compliment.

Children, read this thread very carefully, as this is how a master practices his craft. If a
neck repair deserves to be a sticky, this is it!
 

1981 LPC

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Impressive save. You'd never guess that neck has been broken three times after it's painted.

Curious to find out where the owner is going to place the fourth neck break.
 

jonas335

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I'm thinking this must have been pretty close to that line where it's easier to build a new neck than repair the old one.
 

Pete M

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And people go on about volutes like they will make necks less prone to breaking! :laugh2: I think maybe it is all the string tension over angles that make Gibsons so delicate. You drop a Fender and you can just pick it up and keep playing. With the splines it seems to me they add strength, but there's nothing to stop it breaking around them with enough force applied. There's nothing to stop it breaking again full-stop really. No guitar repair guy ever handed back a guitar to a customer with the words "Here you go, now it is indestructible!". You could've done a fine job with a new headstock scarf or building a new neck and this guy would've broken it a week later anyway from the looks of things. Chuck in a stand and straplocks when you send it back :D Great thread. What model was it?
 

fumblefinger

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Marvelous narrative. I'm glad you brought up the issues with the different rates of expansion for the maple and the hog. And the fact that it is possible to make it too stiff. And the issues with lack of good material. I like that I see someone using a structural epoxy. Great thread.

Sticky?
 

David Collins

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Had a re-broken headstock in an old Guild acoustic bass with maples splines in a mahogany neck come through the shop Monday (nearly identical size and length splines). The 2nd break wasn't quite as bad, but still going to take a lot of rework. The quote was more than they could put in at the time so it didn't stay in the shop, but they called back to say they should be coming back to have the work done in the next week or two. If it does make it in, I'll post some pics here.

I agree with your points, and had to explain in similar terms to this client as to how although splines can have their place, this example showed how they could do more harm than good if not done properly. If this one comes back it may involve a back strap in the final solution, but we'll see.

Excellent post.
 

NimrodPiles

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That was extremely impressive indeed.

Thank you for that post.
 

mux164

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very impressive, especially with a black finish, pretty soon i am going to swear off doing black guitars, my skills arent there yet to get a flawless finish like that
 

bhmcintosh

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Nice job putting that train wreck back together. Good warning about the maple splines in a mahogany neck. One thing I've noticed about BCRGreg's repairs - if he's gotta use splines, he's always careful to match the wood. I've had the odd piece of furniture come apart where different species of wood were glued together.
 




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