MIMF

by **Carl Kaufmann** » Sun Jul 22, 2018 4:18 pm

Suggestions welcome on removing a bound, ebony fingerboard from a mahogany neck on a six-string acoustic guitar, without destroying the fingerboard. This is a blue guitar I built for a friend, and it needs a change in neck angle. Cannot correct with the adjustable truss rod. Neck is mortice-and-tenon, bolted and glued, so removing it for a standard neck reset would be a big headache. Before tackling that, I thought I would try to correct the angle by inserting a shim -- i.e., remove the fretboard, glue a shim the full length of the neck, taper and flatten that, and reglue the fretboard. A narrow shim -- ⅛" or so -- would give me the correct string clearance and saddle height. No, I cannot thin down the mahogany neck: It has a pair of fixed graphite rod braces epoxied into it, on either side of the adjustable rod, and the neck is already thinned to the at minimum at the nut, like a Gibson neck.. Yes, the edge of a shim would show from the heel to the sound hole, but I can live with that. Probably that seam would be covered with a new white plastic binding.
But the question: How to get that fingerboard off without destroying it? It is glued down with LMI guitar glue. And yes, it is important to save the fingerboard, as it is inlaid with Paua shell in a custom design. I can easily refret if necessary, but it would take many hours to redo the inlay, assuming I had the Paua.

by **Bob Gramann** » Sun Jul 22, 2018 4:33 pm

The LMI glue releases with heat. I use a small model airplane heating iron which is about the width of a fingerboard, but a clothes iron, or an iron block heated on the stove, or another heat source you can imagine can be used. Protect the finish from the heat. As you heat it, working from one end to the other, you work a thin spatula into the joint separating it as you. Patience is worth it. The more you let the heat do the work, the less damage you will do. It will take a while. If you've never done it before,you may wish to glue up a dummy neck and fingerboard, let it cure for a couple of days, and take that one apart first to get a feel for the process.

by **Mark Wybierala** » Mon Jul 23, 2018 11:07 am

I had to replace a trussrod on a Ric once so I hung three heat lamps in a row over the fretboard and covered the rest of the guitar with multiple layers of loose tin foil. I spread little pieces of white paper on top of the fretboard thinking that they would turn brown if they got too hot. It took three hours for the glue to soften and the fretboard released with the help of a modified putty knife. It worked. This is a method that you do not want to leave unattended.

by **Carl Kaufmann** » Tue Jul 24, 2018 10:52 am

Thanks for confirming that heat will do the job-- but I am still concerned: How much heat is too much?? I have some ¾" aluminum plate stock that can be cut to fingerboard shape and heated to any desired temperature. That would make a great heat source. If it lifts the frets, no problem? I can pull them out anyway. They can be replaced. But what about the inlay? This is Paua about .050", set in epoxy blackened with graphite powder to match the ebony of the finger board. I think epoxy goes gooey at well under 200 F. Will the fingerboard glue soften at a lower temperature than the epoxy, or am I going to ruin the inlay? How about trying to saw the board off with a Fein tool? They have an oscillating blade that is thin and flat, and it is long enough to cut the width of the board. If I lose 1/16" or so of wood on the neck or fingerboard, the shim could be made thicker to compensate. Interesting challenge, no?

by **Bob Gramann** » Tue Jul 24, 2018 11:21 am

Yes, the heat will probably release your inlays, too. Save them and reinstall them, if necessary. I worry that sawing off the fingerboard will leave you with a messy, irregular surface on both sides that you will have to clean up resulting in even more wood loss. You can glue up some dummies with scrap wood, let the glue cure for a couple days, and experiment with temperatures. Up to char temperature, the hotter you make it, the easier it will be to separate the pieces.

Is your neck joint really irreversible? Would the new StewMac heatstick neck removal tool (https://www.stewmac.com/Luthier_Tools/T ... moval.html) help you undo it? I haven’t tried it, but I’m tempted the next time I have to do a reset. Up till now, I’ve used steam. I would expect that to counterindicator for removing the neck would be the possibility that releasing your joint might require enough heat to release other joints that you want to keep (like all of the glue joints to the head block). I don’t glue my bolt on necks.

by **Brian Evans** » Tue Jul 24, 2018 11:50 am

Have you asked yourself why the neck needs a reset (or change in angle)? It might be that shimming the fretboard is a transitory repair, if the change in angle is cause by body movement and not by the neck joint failing. I'll tell you what I would do in that case, if this happened to a guitar I had made. I would remove the fretboard with heated thin spatulas, NOT with heat from above the fretboard (to preserve the inlay work), I would preserve ditto the headstock inlay (or prepare the headstock for a lap joint) and I would replace the neck, cutting it out of the neck block and re-making that body mortise. I would absolutely not glue the new neck in if I used a bolted joint. My current guitars are using a single furniture bolt and I have one that's been completely stable for two years, yet I can take the neck off in five minutes, four of which are taking the strings off and finding my long Allen wrench.

Coincidentally I saw a blog post of someone doing just this on an ES-335 with that extended tenon/mortise joint that they have. In that case the neck had been ruined by someone thinning it all the way into the truss rod, not a needed reset.

by **Mark Wybierala** » Tue Jul 24, 2018 12:47 pm

I would draw this out as a full size diagram and then rethink the whole process of what actually needs to be accomplished. If it actually needs a neck reset, then a neck reset is what you should do. Its a total waste of time if all of this effort only half-way addresses the real problem.

by **Carl Kaufmann** » Tue Jul 24, 2018 6:23 pm

No, the neck joint has not failed. (Unfortunately) It is rock solid ... The problem is Builder' Error, plain and simple. This careless fool did not fit the neck at the corrective angle to the heel, so from Day One, the strings have naturally been at the wrong height at fret #12. Trying to force the neck to correct the mistake puts way too much load on the truss rod. Lowering the saddle will not do nearly enough.
You are probably right: the two-bolt neck joint, with a straight tenon, probably needed no glue in the first place. I added glue to the mix thinking that this would make a more solid connection, the better to encourage the sound to run up and down the neck. Does that really make a difference? Who knows? All I know is that the owner loves the sound of this guitar, and will probably kill me if my repair job wrecks it. She is a toxicologist, specializing in exotic poisons, and she could do me in without leaving a trace.
But no matter how I remove the fingerboard now, there will still be an issue with the glue joint between the top and the fingerboard extension. And removing and rebedding the Paua inlays could be a challenge, as the pieces are quite large. They are decorative shapes, and not just little position markers.
All things considered, Plan A now is to try to make the separation with hot knife, working just in the seam. Failing that, Plan B would be to heat the whole fingerboard, maybe deliberately removing the inlays in advance, one by one. Plan C is to make a new neck and look for new pieces of Paua as necessary. I know that beautiful stuff is available washed up on the beach at Wellington NZ. That's where I found it before. I am leaning toward Plan B.

by **Mark Wybierala** » Tue Jul 24, 2018 11:03 pm

The heat required in a fingerboard removal is only enough heat to soften the glue joint. As I did on the Ric I repaired, I used heat lamps about 12" from the fretboard to slowly heat it up. This fretboard had inlays and the additional complication of having that awful gloss catalized finish that only Rickenbacker uses on top of the rosewood. Neither the inlays or the gloss finish of the rosewood was damaged when I removed the fretboard. If you use heat, just apply it slowly and monitor it. Unfortunately, wood is a good insulator and it takes a very long time for the heat to travel through the fretboard to the glue joint. The Ric took three hours for the glue under the fretboard to soften. I employed a modified cymbal stand that had one of those counterweighted booms to hang three 250watt heat lamps so I could easily raise or lower the lamps. I used small shreds of white paper laying on top of the fretboard to indicate if the surface temp got too hot (that wasn't a good idea cuz paper turns brown at a temp too high) but now you can buy one of those laser dot non-contact surface thermometers for under $20. I got one last year and have found all kinds of uses for it. Your inlays should survive just fine if you can apply the heat evenly and slow over a long period of time.

by **Brian Evans** » Wed Jul 25, 2018 8:45 am

The epoxy holding the inlays will start to degrade relatively early, around 50C, or maybe 130F, lower in high humidity. But the good news is that it doesn't fail completely, rapidly, or go runny, and it's strength returns when it cools down. The reason you use epoxy for inlays is gap-filling, not strength, anyway. I would probably go more for the hot knife technique first, save the big heat for later, since I've seen people doing that for the extension over the body all the time. I need to remove the fretboard on a 1935 Dobro at some point, so I've been researching all the ideas - but haven't made the leap of faith yet!

by **Clay Schaeffer** » Sun Aug 05, 2018 9:56 am

Are you sure you need to remove the fingerboard? The usual technique is to remove a fret over the neck pocket and inject steam into it. This may not work with a mortice and tenon, but I would try that first. Another (now less accepted) method is to cut through the fretboard at the fret at the neck /body joint. Only remove the fretboard that is over the body to gain access to the neck pocket. After the reset you would have to rebind the fretboard or do an artistic repair depending on how it is bound.