Warping ebony fingerboard

[Mike Kolb]

About a year ago, I replaced an ebony fingerboard on a Beard resophonic.  Pretty standard install... the board over the neck was glued and the extension over the body was mechanically fastened with small bolts from inside, as had been the original board.  New frets and away we go. No binding needed.

A few weeks ago, the owner called and indicated the board had recently warped-up a hair less than 1/8" but only on the bass side and only at the extension end.  He's going to get the guitar to me and I'll see what can be done for a fix but, in reality, I'm expecting a total re-do with a new fingerboard.

The slotted fingerboard came from a known, reputable source and was flat as a pancake from the time I opened the box until the time it left the shop.  What happened after that is anyone's guess, but the owner takes pretty good care of his instruments.

So my question is:  if (or, when) I install the "newest new" fingerboard, are there any preventative measures to take that might prevent this from happening again?  Maybe shellac (or otherwise) seal all the surfaces that aren't actually being glued to the neck?  Or something else entirely that would help keep a straight board straight? 

[Paul Breen]

Obviously, you will need to inspect the guitar first hand. Seems suspect to me that the board could warp up an 1/8" on the bass side and not bring the top along with it? My guess is that one or both of the screws has come loose to allow what you have described. If the top has pulled, then there should be a structural reason for it. I can't fathom that a slotted 1/4" Ebony board could warp with enough strength to deform the top an 1/8".
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[Mike Kolb]

What you say sure seems right.  Yes, I'll need to give it a look-see when I can get it on the bench.  Here's a couple of "in-progress" shots taken when the new board was being installed last year.

One thing that (now) also seems suspect is that screws are holding only on the centerline of the fingerboard, and the rectangular plate simply sits (unglued) into the shallow mating pocket. Hmmmm.

It'll be interesting to see what's actually going-on in there.  Seems there's one of a few things that may have given way. To be continued, and thanks for putting on the thinking cap!

[Paul Breen]

Yes Mike, rather iffy design to have the screws stacked like that and expect the fingerboard extension to never curl. Typically, they are configured side by side, with the bolts hidden under dot markers with traditional designs I have seen. Maybe that bit of plywood should be glued to the back of the fingerboard, should help keep the fingerboard from curling.

[Mike Kolb]

I didn't describe the setup very well...  that plywood oblong piece is, indeed, glued to the underside of the fingerboard and that piece then "nests" into the matching cutout on the body.

The bolts go through the body and into the tee-nuts on that plate.  The underside of the fingerboard has very shallow circular reliefs for the heads of the tee-nuts. 

So maybe the glue failed there?  Or, as you'd mentioned, maybe one or both of the bolts let go. We'll hafta' see.  The owner's out-of-state and will be dropping-off the guitar over the holidays.

Whatever presents-itself should be interesting ...and I'll be sure to update as it unfolds.

[Mark McLean]

The current setup has the bolts pulling down on the centre line of the FB extension but potentially allowing the edges to do their own thing.  Could you change the bolts to north-south positions instead of the current east-west layout (or add two more) to pull the edges down?

[Mike Kolb]

That's definitely an option to consider, Mark.  It'll be interesting to see what "let go" but I'm thinking it's either a glue-failure of the plate to the fingerboard, or the bolts worked their way out.  In any event, changing the bolts direction could only improve things.

On the other hand, there's a ton of Beards out there with that design and this is the only one I'm aware of that's exhibited this problem.... so my jury's out 'til I can get my grubby little hands on it.

[Mark A. Kane]

In case all else fails, here's a simple plan B. Remove the plate altogether. Score the top around the fingerboard and remove the finish inside the perimeter. Glue the fingerboard to the top, à la Collings or old Taylor. Use hide glue because, well, everything's better with hide glue :)

[Mike Kolb]

Not a bad idea.... it's done well for Martin and others!   I do, however, like the ability to mechanically take the take off as needed. 

Having said that, if it takes a 'permanent' solution like gluing the extension down to the top then so be it.  Can't wait to see what's going on with this thing in-person.

[Paul Breen]

Putting the cart in front of the horse a bit because I know you haven't inspected the guitar first hand yet but another solution comes to mind that would be both enduring and keep the neck easily removable. (I was also sitting here bored and needing a project)

I recently added carbon fiber rods to a Banjeaurine finger board extension. This is a turn of the century, short scale 5 string SS Stewart banjo with an unsupported finger board extension. Slotted for frets, unsupported extensions like this are very prone to drooping over time as this one did. The images will explain more than I care to type...

This is the banjo, with it's headless neck (fodder for another thread) before I pulled it apart, so you can see how far the cantilevered finger board extension extends.

With board off, I routed grooves for the carbon fiber rods. There are many X by Y dimensions available, I bought some .070" X 7/16" for the project. Thin enough that I wouldn't need to rout into the fret slots but still plenty strong. The area that looks like it has chisel marks, is right where the neck heel ends and the finger board extensions starts. I have left enough space there for a good glue bond at the neck heel to get good anchoring for the rods and cantilevered extension.

It is glued in with epoxy. I endorse West System epoxy, great stuff, very hard when set and tools/ sands easily. I added Black tint to the epoxy, just for the sake of attention to detail. No need to clamp down on the rods, the work just needs to be held flat while the epoxy sets.

After sanding...

Now, I'm sure you don't want to remove the finger board again, I wouldn't but I think that if the end of the finger board does turn out to be warped/ curled, a carbon fiber rod(s) could be installed at a right angle to the board, toward the end of the extension. That could probably be managed without finger board removal.

[Mike Kolb]

Yowzuh... now that's a good fix, Paul!  My original thinking was that, since the board on this Beard is now warped, I'll have to remove & replace it, but your idea gives me some hope! 

Even if it is warped-up, I can leave it attached to the neck, flatten the warped extension (even temporarily) and then utilize your carbon fiber insert to lock the newfound flatness in.

Great idea and you presented it quite nicely.  Thanks! 

[Paul Breen]

Thought you might find this interesting.

[Mike Kolb]

Resurrecting this thread now that the "patient" is in-hand and apart.  Yep, it looks as though the ebony board simply warped for some unknown reason at the end, over the body.  Had it been attached directly to the body, it would've certainly pulled the top up with it, but the sacrificial lamb here was the small mounting plate. The plate (mechanically attached to the top with two machine screws) held fast, but the strength of the warp was sufficient to pull the glued plate from the fingerboard.

Pics attached.

The f'board is toast so I'm gonna' start this project from scratch. The owner would like wider frets anyway, so that's yet another (although minor) reason to bail-out and start anew. 

Being somewhat gun-shy at this point, I've been thinking about a more stable ebony alternative.  Does anyone here have experience with Richlite® fingerboards?  I see LMII carries them and offer the same custom slotting, etc.  Are they, in fact, as stable as they're purported to be?  How about gluing options?  HHG and Titebond are OK?

Beard seems to make a real good reso guitar, so I'm not going to be trying to reinvent their wheel, as far as the attachment system goes. But I'd like to take every step necessary to not have this happen again! 

I'm still very intrigued with Paul Breen's idea of epoxying long carbon fiber slats at the end to keep everything as stable as possible. The small mounting plate could be epoxied to them (and the f'board around them) and yet, because that plate is mounted to the top with fasteners, the assembly can still be removed if needed.

Anyway, that's where all this sits.  As always, open to ideas and thoughts..... thanks.  Oh, and happy new year!