Neck glue question

[macatticus]

I recently set the neck on my IV kit and got to thinking...
Is it advised to also glue under the fretboard (where there is slight neck wood still) to the body? I only glued the neck cavity and I'm afraid there may not be enough hold to withstand the strings. I've pulled and pushed on it and it isn't budging but I'm not sure I have the best knowhow on this. Thanks!

[macatticus]

No one has any advice on this?

[sunburst]

I don't understand the question. I'm not familiar with the IV kit neck joint, and can't visualize it from your description.

[Michael Lewis]

If your neck joint fits well, if you haven't carved the top too thin, if the joints of the top to rim and neck block are good, it should hold well. If any one of those items are not up to snuff you could be in trouble.

[macatticus]

It's a little hard to explain.
There is the neck joint (which I glued)
There is also a spot where the fingerboard extends over the body about 3-4 inches. I did not place glue under this area and I wasn't sure if I was supposed to. I only placed glue in the neck joint.
The joint itself does fit nicely and the top is roughly the same depth as it was when I got it. Guess I'm good.

[Geoff B]

Does the fingerboard float over the top, or is it in contact with it? I'm not familiar with the IV specs. It sounds like you attached the fretboard to the neck, then glued the neck to the body. Is that correct? A picture could help out a lot, because like John above, I'm having trouble picturing your situation...

[Hans]

If you are talking about the fingerboard extension support under the finigerboard, yes, that should be glued to the top. Some folks also do what Gibson did and put a large screw in there before glueing down the F.B. but I don't think its necessary. I'd recommend a pallet knife and glue, then clamp.

[macatticus]

I'm pointing to the area which I did not glue. What would you suggest now that it is already set? Should I get a small screw and attach it?
http://farm5.static.flickr.com/4016/4257055018_79bae382c0_o.jpg

[sunburst]

Yes, that should be glued. I'd try what Hans said; palette knife, glue, clamp.
The screws Hans mentioned were under the fingerboard, can't do it now, this is a slightly different construction than that which used the screws, no need for a screw.

[macatticus]

Its glued so tightly I don't know how I'll get the glue under there. Can you explain the process?

[sunburst]

A palette knife (from an art store, there are various types) has a very thin metal blade. Put some glue on the palette knife and work it under the fingerboard extender. Keep doing that until you have glue under there the best you can, then clean up the surrounding area with a damp rag. Put a wooden caul over the frets and one over the head block at the back surface to protect them from the clamp jaws, and clamp the joint until the glue dries.

[bennyb]

Howdy Mac,
I'll go against the grain here, and suggest that you're done with this section of assembly, and it'll work out fine. That's assuming that you got the neck joint itself well glued with competent glue, and your dowels are fit and glued well. From your picture, it looks like there really is no air at all, and I think you'd just make a mess to no good effect, by trying to push, swipe, inject, or transmigrate glue in there. By the bye, I've got a couple of IV kits, I play 'em nearly every day; they're not glued there either :-).

benny

[sunburst]

OK, here's why I think it should be glued.
The strings will be pulling on the neck in such a way that it will act as a lever to try to rotate the neck heel, and since the heel is glued into the head block, rotate the block too. The rotation is such that the fingerboard surface of the neck "tries" to move toward the bridge location, and the end of the neck heel "tries" to pull away from the body. That force puts a sheer load on the joint between the fingerboard extender and the top so that the extender "tries" to slide along the top in the direction of the bridge. A securely glued extender not only stays in place better, but it also lends strength to the neck joint by resisting sheer and providing more resistance to string pull at the neck joint.
The sheer movement may not be apparent in the early life of a mandolin, but the hundreds of pounds of pull applied by the strings to a constantly strung-up instrument never sleeps! If the glue a type that can creep over time, it will, and if the instrument is ever left in the trunk of a hot car things will move.

[Gail Hester]

My concern with not getting some glue in there is that the instrument may have or develop a vibrational rattle.

Posted at the same time, agree with you John.

[Dale Ludewig]

I agree with John and Gail for the same reasons. It needs to be glued. A screw doesn't serve the same purpose. I'd even go so far as to say that if necessary you might drill a little hole on the treble side of the extension support and get some glue down there that way. Between a palette knife and a little rocking you should be successful.

[nhanduti]

hallo,

in my kit, i've cut out a part of the neck extention and put another extention (mahogany) like the photos. but i agree with John and Gail too... I didn't use a screw. my reason to do that was that i thought the neck extention glued in the top woud "kill" some vibrations on the top so, "kill" some sound too, but make the finish (french polish) a bit difficult to do under that.

ciao!

[macatticus]

So some say do it, others say don't.. I guess I have some thinking to do!

[Fretbear]

Is the back on yet? If not you could drill a tiny hole from the backside to inject the glue through.

[Geoff B]

I'd think if you can get glue in there, you should. It'd be no fun to find out later that it rattles or is moving on you... On the other hand if you think it is solid enough, then it's your mando and you get to do with it what you want!

[macatticus]

I think if I pry it up and stick two small blades in, I can then inject another blade and glue from the sides.

[Bill Snyder]

So some say do it, others say don't.. I guess I have some thinking to do!

Yeah, but the ones saying do it are top notch luthiers.

[macatticus]

I did my best to pry the neck back and put glue in the side as best I could. I guess We'll just have to see how it turns out! Thanks guys!