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Hi

The neck on my 12 string build will be attached shortly, it is a m+t joint with 2 bolts.

When doing the trial fit the fretboard extension sits really tight against the body.


I'm wondering would I get away with leaving this un-glued?


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I don't glue the extension the wedging action of the fret tags tend to put a slight bow in the FB so the extension compresses nicely against the top. An alternative is to just put a dab of glue still making it easy to remove the neck without causing damage.

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Ken Cierp

http://www.kennethmichaelguitars.com/

This comes up every so often and basically there are those that advocate for or against it. So you are probably fine either way. Having said that IMHO I view that as a structural part of the joint and I just don't like loose parts. So I glue it. Either way, just make sure it fits tight.

On one of my early guitars I chased a subtle buzzing sound for quite some time before discovering it was emanating from the area of an unglued fingerboard extension. The pieces were well-mated and appeared to fit together tightly. Just sayin'.

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George :-)

huh??


Structural issues aside, I can't imagine getting a decent fret dress on a fret board that was not glued down.
12 strings need all the help they can get IMO.
Regular Titebond releases easily just above room temperature with no top or fingerboard damage. It might be one of the few places it has the advantage over hide glue.

FWIW, I follow Hesh's advice of a dime sized puddle of TB under the extension. It's super easy to take off again with just the slightest amount of heat and that fancy SM bridge removal tool.

Agreed with David though, I would be worried about the fretting side of things. Maybe put some fall away into the extension frets when leveling them? Hesh and Dave have a technique of putting a layer or two of tape at the end of the leveling beam and then letting the tape ride on the fret above the extension (12 or 14 or whatever) to put some fall away into the extension frets.

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We glue all extensions that are not bolted down - we have seen an unglued extension act like a reed on a woodwind and buzz against the top when relative humidity changes or age-related changes occur in extension geometry. Like others suggested, we run a bead of glue around the perimeter to provide a 1/4"- 3/8" band of adhesive on the edge - gluing the entire surface of the extension is not necessary and makes removal more difficult.

On milling fall-away into the extension or frets, another approach is to cut a file folder in half at the spine, wrap half around the neck to provide a smooth, uniform surface that will conform to the fret board, then use the other half by folding as necessary to provide the needed shim height. Rest one end of the sanding beam on that shim - it will slide nicely on the cardboard surface without hanging up on anything. Some chalk on the fret board extension or Sanford Sharpie ink on the frets in the extension area will permit monitoring of progress to the desired fall-away.

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Or just don't worry about fall away as it's not needed

Woops can-o-worms.

But seriously the first ten or so guitars I built with 'fall away' because the neck angle to body top geometry was not exactly right so I clamped the extension down and voila! Fall away. Yeah I know that's not right but because that drove me nuts I finally figured out how to get the geometry perfect so that relief goes from the nut to the end of the fret board, or it's dead straight by choosing. That to me makes me smile. <--- see?

You've got good company Woodie G

Collings:

Glue it.

I got the idea of a small puddle under the extension from Mario P. Thanks Mario for this and a million other great ideas!

David's comment about having a solid fret plane to level, dress and induce fall-away resonates (pardon the term... ) with me too. Loose frets and a unglued extension kills the precision of the fret work.

Woodie's comment about the reed also is indeed a realistic consideration.

George's real world experience with a vibrating extension should get folk's attention or folks like David F., Woodie and I will be billing your customers some day to fix a loose fret board extension.... With that said maybe nix the glue, it will be fine.....

JF's comment I respectfully disagree with. Not all playing styles benefit from fall-away true but a bluegrass guitar with mediums played in a band with a banjo most certainly does.

Fret work is a funny thing in so much as most of the time a dread with mediums used for bluegrass need not have perfect fret work. The action is higher, 5 and 7 respectively and the strings being more massive lash out less because of the physics of having more inertia to overcome.

OTOH the finger style player who likes low action and 12's does benefit from fall-away and good fret work too.

Shredders can be fine with a perfectly nearly.... flat fret board, fall-away not required but it doesn't hurt either. That is until the RH changes and it rains outside.

Any bolt on Fender style electric neck is subject to "curling" over time at the end. We call this "ski ramping" and see it every day. It's the opposite of fall away and often the single most limiting factor to a great set-up that we encounter. Neck through designs don't see to do this. So in a sense even with electrics with a bolt-on Fender style neck fall-away is important as well if not out right required....

Anyway I believe that Mario also used Elmer's wood glue for that small puddle under the extension.

Lastly only about 20,000,000 guitars have been built without fall-away so JF is right it's not always required but it can at times be necessary for certain playing styles and when that pesky banjo is around and you need to be heard.

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Ann Arbor Guitars

I'd say glue it for sure. You avoid a source of unwanted noise, allow more accurate fret dressing, and I think it acts as an additional brace preventing head bock rotation.

This was brought home to me when I was doing a neck reset on a bolt on neck. I got it perfect so the angle was good under string load without gluing the extension. Then I glued the extension and it did not move as much resulting in a saddle that had to be a little higher than I wanted.

I usually put a line of glue along the edges and end about 1/4" wide.

Drop off? I usually try to get the amount under no tension that will result in a straight or very slightly dropped off extension under string load.

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It's not what you don't know that hurts you, it's what you do know that's wrong.

I just glued the fretboard extension for the first time. I had never had issues with buzzing or hearing the overhang vibrate on the top, but when I thought about how much work I put into have a flat fret plane (prior to putting relief in myself), it didn't make sense not to control it.

I use 4 drops of this https://www.walmart.ca/en/ip/elmers-was ... AqXS8P8HAQ

There's no need to glue the heck out of it and this glue releases very easy with minimum go heat.

I often don't glue them down till I'm ready for final set up. Nothing wrong with playing the heck out of them for a couple of weeks.

Good Luck! Let's see some photos.

If you have to play notes above the 14th or 12th fret body join (As I do on occasion) you may find that the notes are somewhat "dead" with an unglued extension. I have a couple where I left the extension unglued thinking I might want to rework the neck and have noted that problem. Probably not an issue for most.

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Steve Smith
"Music is what feelings sound like"

If you are going to do a bolt on neck to facilitate future neck resets, why not bolt the fretboard extension as well? It isn't that much more work, compared to releasing a glue joint. I see that if you are doing a glued neck joint, gluing the extension makes sense. Sorry for going off topic here!

Alex

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"Indecision is the key to flexibility" .... Bumper sticker

In the real world, guitars are subjected to stresses such as knocks (sideways ) to the headstock, which are much more effectively counteracted by a glued down FB extension rather than by the impact being sustained purely by the shoulders of the neck heel, which would be the case with a floating FB extension.

I have pulled a number of gibsons that had the puddle
I also chased a buzz on an unglued fretboard. If you don't glue it you can also bolt the extension not had either way

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John Hall
blues creek guitars
Authorized CF Martin Repair
Co President of ASIA
You Don't know what you don't know until you know it

I can see how it would be possible for an unsecured extension could cause a buzz if not compressed against the top, if that is the case by all means add some glue or bolts. As for structure let us not forget that arched top guitars have extensions that float above the top as do instruments in the violin family.

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Ken Cierp

http://www.kennethmichaelguitars.com/

I'm thinking even if an extension is tight against the soundboard on day one, with RH changes don't expect it to stay that way.

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Joe Beaver
Maker of Sawdust

I know over the life of a guitar the tendency is for the neck and the heel block to roll forward under tension. It seems to me that a properly glued down fretboard is not just keeping the extesion tight to the top but it also provides a pretty significant brace tying the heel block to the transverse brace that would help to counter that rotation. Has anyone measured the action on a new guitar before and after the fretboard extension is glued down? I suspect even in that case there can be a measurable difference.

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I have also had the experience of an unglued, but seemingly tight-fitting fingerboard extension causing a buzz. I agree with the suggestion to do a full bolt-on, bolt-down arrangement. Easy and effective

Yes. See my earlier post in this thread.

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It's not what you don't know that hurts you, it's what you do know that's wrong.