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? 

[Richard Bales]

The story is there in the end grain.  The board was flat sawn fairly close to the centre of the tree.  The consequence is that there will be more lateral shrinkage/movement on the bass side than on the treble side.  And since the growth rings are further spaced on the bass side, there will certainly be an imbalance in the board as it reacts to changing RH.  So, not an ideal slab for a fretboard.  But that's pretty obvious now.

[Mike Kolb]

Right... and that appears to be the only viable perp remaining in the lineup!  The board was purchased (custom cut to scale length & slotted) from one of the "mainstay" suppliers that we've all done business with.

I brought the problem to their attention and the only reply I received was a link to an article on "how to properly store your wood".  Huh?

Wasn't looking for a refund or replacement since it'd been about a year between when the purchase was made and the twisting issue arose...  just wanted to let them know about how the fingerboard was cut and what had occurred as a result.  Arrrgh.

Anyway, it's water under the bridge at this point.  A newly-purchased Richlite® fingerboard is on the way and I'll do this all over again with, hopefully, a more stable result :)

[Mark McLean]

Hi Mike, and HNY to you too.  Your thoughts on this seem sound to me.  That fingerboard certainly does look unusable.  If that is the grain pattern that we can see in the endgrain (always hard to pick with ebony) it seems to be flat-sawn, which may be the genesis of the problem.  I have not used any of the synthetic ebony alternatives - but I have heard good reports from folks who have used Richlite.  It would seem to be an appropriate choice in this case.  I hope you don't have any trouble getting that board unglued. 

[Mike Kolb]

Thanks for the input, Mark.  I think you're correct regarding the flat-sawn cut of the board, so any thoughts harbored about "saving & fixing" it went out the window. The old board came off yesterday with no issues.  Also ordered a new Richlite® slotted board from LMII so at least things are moving-along. 

The head-scratcher, of course, is wondering what can be done differently to prevent this from happening again.

Instead of losing sleep, however, I'll press forward and chalk this experience up to a wonky piece of wood :)

[Paul Breen]

I agree with Mark, the finger board has cupped from the grain orientation and nothing to stop it from doing so. I can't help but think that there are more Beard resonator guitars out there with the same problem, the extension connection is inadequate.

Mike, you never said what the problem was for the original board that prompted replacement, a similar issue?

Cupping or drooping finger boards are an old problem that is common when they are unsupported. This is an image of the same finger board I installed the carbon fiber reinforcement. The end edge of the 100+ year old finger board was kerfed and a spline added in an attempt to control this. It was had to get a good picture but you can just make out the Ebony cross ways spline. No two boards are the same so it's a crap shoot if there is no support. 

This board still cupped slightly in spite of the added spline. I still think that an epoxied in carbon fiber reinforcement would control this, wood doesn't have the back bone. Not sure if this strategy would have let you flatten the Beard fingerboard, bad as it looks but would likely be a good reinforcement as a preventative measure.

Looks like you have things well in hand, the worst is over with the fingerboard off...what a pain.

[Mike Kolb]

Hey Paul.... good question!  This all started when the owner was unhappy with (1). the appearance of the maple binding that was present on the original ebony fingerboard and (2). the somewhat fanciful fret markers. 

He wanted a more "austere" look, so he opted for a plain-jane ebony board with no binding and simple small dots for markers.  I agreed to do the work.... and look where it got me :)   Sigh, no good deed goes unpunished, as they say.

Anyway, fast-forward to today and the new Richlite® fingerboard blank has arrived and I'll start again.  Since it's a man-made slab and has no grain orientation, I'm pretty sure the cupping and RH issues may be a thing of the past with this one. 

By the way, I'm really impressed with this Richlite® board, not knowing exactly what to expect.  It's appearance, weight and color are indistinguishable from ebony.  LMII advises, however, to rough-up the gluing surfaces a little more than usual.  It also seems to be a bit stiffer (end-to-end) so this project may finally see a happy ending. Yay! 

I'm "tucking-away" (for future use) your great idea for the carbon fiber reinforcements... thanks for sharing it, as it's something we can probably all use down the road at one time or another. 

[Mike Kolb]

Finally got this job behind me!  The new fingerboard lies dead-flat... as it should... and I'll keep my fingers crossed that it stays that way.  

It's the first time I've worked with the composite Richlite® material. One observation I'll pass along is that there's very little "give" when fretting, so heads-up for encountering some back-bow if the slots aren't a generous match to the the fret tangs. That said, the stuff is a dream to work with and the color consistency is great.

Thanks for all of the input, suggestions and comments as this thing progressed.

[Paul Breen]

What did you end up using for glue? I'm sure your glad to get this behind you, looks great Mike. 

[Mike Kolb]

Yep, glad, indeed! 

After a good scuff-up on the bottom of the fingerboard (that was per LMI's advice) I used regular TiteBond for gluing it to the neck and it held nicely.

However, on that small plate with the tee-nuts, I opted to use epoxy to glue it to the underside.  My thinking was that (a). the system can still come apart if needed and (b). I really, really didn't want that plate to pull off again! 

As we speak, it's all boxed-up and ready for shipping-out this morning.  That's a good thing!