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Vespa Bob
04-26-2016, 05:56 PM
I'll soon be gluing the bridge on my present project and, since it is the first ebony bridge I've used, I'd appreciate a little advice. The wood is obviously very oily and I seem to remember that one has to treat it by rubbing it down with acetone or something similar, but, I'm not sure. So, how does one prepare an ebony bridge for gluing? Also, what glue, Titebond, or epoxy, or hide glue? Thanks.

Bob

sequoia
04-26-2016, 06:21 PM
I would say that ebony as a wood isn't necessarily that "oily", just damn hard. Sure you can wipe it down with a solvent like acetone, etc. which won't hurt and can only help. My thought is that ebony can get almost glass smooth if sanded too fine and you might want to scuff it a little before gluing.... Definitely do NOT use epoxy. Titebond will do just fine. Hide glue I have no experience with so can't comment, but would probably work just fine. ... Re-reading your post you say that your ebony is "obviously very oily". Real ebony should not look oily which makes me wonder whether you are looking at some sort of treated wood. "Ebonized" something? As posted on here earlier: There are lots of different "ebony" woods and the term is almost meaningless. Some Dalbergia species are quite oily. In my experience, the "real McCoy" or west African Gaboon ebony is not a particularly oily wood. Send pictures!

Allen
04-26-2016, 09:39 PM
I just sand them with P120 grit to fit the contour of my soundboard prior to glueing. Blow dust off and use either Titebond or HHG. Never Epoxy.

Michael N.
04-26-2016, 10:07 PM
I don't use ebony anymore but when I did I used Hide. Hide distorts the gluing surface though, largely because it's water based and ebony reacts readily to humidity changes. I would scrape the underside of the bridge and then size it with HHG. Allow it to dry and scrape the distortion out, then glue the bridge.
It glues well though, no need for the acetone or any other solvent.

Vespa Bob
04-27-2016, 10:59 AM
Thanks for the advice, everyone, Titebond it will be then. I will scuff up the underside for good measure, though. The bridge material is W Africa ebony. Sorry that I forgot to mention that. Also, "obviously oily" I admit was a bit of an exaggeration, more like "slightly greasy" would be more accurate!

Bob

mikeyb2
04-27-2016, 11:42 AM
I built 3 banjos last year, 2 with rosewood fretboards and one with ebony. The ebony one started to lift after gluing to the maple neck, so I had to remove it with heat and palette knife. It was a PITA to get off, so when I'd cleaned it all up and removed the old glue(Titebond), I gave it a good rubbing down with Acetone and glued it up again. No problems since. Some may disagree, but I wouldn't glue ebony again without cleaning with acetone, a lesson learned for sure. After all, it can't do any harm if you have some at hand.

PhilUSAFRet
04-27-2016, 12:47 PM
Wondering if the problem is in the dyes and what liquid is used as a "carrier"

Vespa Bob
04-28-2016, 04:07 AM
Sorry Phil, if this is a silly question, but what dyes are you referring to?

Bob

Michael N.
04-28-2016, 09:05 AM
I built 3 banjos last year, 2 with rosewood fretboards and one with ebony. The ebony one started to lift after gluing to the maple neck, so I had to remove it with heat and palette knife. It was a PITA to get off, so when I'd cleaned it all up and removed the old glue(Titebond), I gave it a good rubbing down with Acetone and glued it up again. No problems since. Some may disagree, but I wouldn't glue ebony again without cleaning with acetone, a lesson learned for sure. After all, it can't do any harm if you have some at hand.

That's probably because you forgot to damp the top surface of the ebony. It has nothing to do with cleaning any oils from the wood. Either that or the glue skinned over before you got the clamps on. I've glued countless ebony fretboards and they don't need any solvent. If you wet/damp the top surface it will counteract any movement introduced by the Titebond.

mikeyb2
04-28-2016, 10:15 AM
That's probably because you forgot to damp the top surface of the ebony. It has nothing to do with cleaning any oils from the wood. Either that or the glue skinned over before you got the clamps on. I've glued countless ebony fretboards and they don't need any solvent. If you wet/damp the top surface it will counteract any movement introduced by the Titebond.
Damping the top surface as you say, is not something I've seen mentioned anywhere, but I take your point and it makes sense. I'll try that next time I use ebony, but I'll probably still give it a wipe with acetone to be on the safe side. Thanks for the tip Michael.

PhilUSAFRet
04-28-2016, 03:30 PM
Sorry Phil, if this is a silly question, but what dyes are you referring to?

Bob

It's my understanding that much if not most ebony (if in fact it's real ebony) has been dyed. Depending on who's doing the dying, can't be sure what kind of dye they used, how long they soaked it, and whether it would impact adhesion. After a little research, some folks make their own dyes. Just wondering.

pointpergame
04-28-2016, 04:09 PM
I resew my own from old, old stock. I could be wrong, but I can't see any way a dye can penetrate a block of ebony. At least beyond a small fraction of an inch. Are you possibly talking about pre-cut fret boards bought from a luthier's supplier?

I've always drunk the rosewood/ebony-is-somewhat-oily cool aide and wiped with naphtha or acetone before glueing. Since I've never NOT done it, I don't have an experimental control to compare it to...but have never had a bridge pop off a guitar or fingerboard de-glue itself. My curiosity is piqued. I would think the guys at Stew Mac would have the authoritative answer. Or Frank Ford at Gryphon. Next time I'm in his shop I'll ask him.

sequoia
04-28-2016, 05:07 PM
Michael is right. Damping the surface of any wood causes the "grain to raise" which is a good thing in this case. Think about little hands reaching out to grab on in a gluey handshake. Hairy wood glues good.... However the OP said his ebony looked "oily" and then "greasy" which leads me suspect that the wood seller oiled the woods before sale to make it look more like "ebony". Therefore, a swipe with a polar solvent like acetone would be indicated. Can't hurt.

mikeyb2
04-28-2016, 10:05 PM
wipe a piece of ebony with a cloth soaked in acetone and see how black the cloth is afterwards. This blackening, I would suggest is the natural oil/resin from the wood, and it comes off readily without too much rubbing, indicating it is an oily wood.

PhilUSAFRet
04-29-2016, 04:54 PM
unless it's dye

Michael N.
04-29-2016, 09:43 PM
I've never come across ebony that has been dyed. If it's been dyed it's probably a processed fretboard i.e. one that isn't supplied rough sawn. The dye will barely reach 0.2 mm's depth in ebony.
Lot's of wood will show a stain when wiped with a solvent and cloth. Indian rosewood will show masses of it, especially the stuff that tends to be very purple. Any of the well known dye woods will show this in abundance. They all glue well with hide glue and I've never pre cleaned them with a solvent. If you read that old Sloane book on guitar making I think that he suggests using benzene on oily woods like rosewood. Probably wasn't the best advice, benzene isn't the friendliest solvent to use. In fact there's no need to use any, at least not on any of the common instrument making woods that I've used.

Vespa Bob
04-30-2016, 11:21 AM
Definitely not dyed. I carved it from a 1/4" x 2" chunk of wood and it was the same colour throughout. After roughing up the back and given it a wipe down with acetone, I clamped and glued it with Titebond. I'm now in the process of nervously tightening up the strings. I've put too much work into this project for things to go wrong now!

Bob

PhilUSAFRet
04-30-2016, 03:21 PM
Good feedback on the ebony. This is a great place to hear from the guys that actually use this stuff. A great and helpful forum.

sequoia
04-30-2016, 06:56 PM
Look, just chalk this up to bridge gluing paranoia and get on with it. Everything is going to be fine. Remember we are talking less than 30 psi on an uke bridge and Titebond is more than up to the task. No problem from a structural/engineering point of view. Just clamp it right and let it dry overnight before stringing up. I've attempted to take off a couple of Titebond glued bridges and I can definitely testify that they are on there really, really hard. Way, way harder than any string tension on an uke will pull off. Rest easy... Better to think where you are gonna glue the thing with proper distance and compensation.