Epoxy on fingerboard: does it stop expansion/ contraction?
A more specifically worded question:
Anybody here have experience with whether EPOXY RESIN on a fretless fingerboard will actually stop or significantly impede expansion/ contraction of said fingerboard?
I'm disappointed with the frequent movement of an ebony fingerboard. (Ebony on Maple). I've never seen as much movement/ frequent adjustments as I have on my two ebony-boarded instruments. I want to see if I can salvage this one by applying epoxy resin. (I know it's sound properties).
But the critical issue is...does epoxy breathe & exchange humidity, or does it effectively seal against such exchange. It's use as a marine coating might seem to make this obvious, but only a straight-up chemist-type answer-or real-world experience will do for an answer.
Got one? I'd sure appreciate it! (BTW, if you use a specific brand or formulation, that's golden. I'm at least learning that epoxy is far more water-resistant than vinylester or polyester, even if polyester sounds great, i.e; Pedulla).
No comment on your question, but as a side note, if you are going to try to epoxy Ebony, be thorough in your preparation, because Ebony is quite oily, and that presents issues with adhesion.
No, the neck moves with weather changes, its not just the fingerboard. Wood doesn't breath its dead. Epoxy will protect your fingerboard from string wear, but it wont make it to where your neck will not move.
Hey Hopkins, thanks for the reply:
Of course you're right, a neck (esp. 1 piece maple) is subject to movement. Acceptng that, I'm of the mind that these ebony boards (one 10 yrs old on a mahogany gtr neck, this one a new USACG bass neck, ebony on maple), both move excessively, due to the relative instability of ebony, and the differential expansion/contraction rate of ebony visa-vis said neck materials. You may know, or agree/ disagree; I'm going on my scant but detailed personal observation, paired with a plethora of respected luthiers (like Sadowsky) who complain of these tendencies in ebony.
I know you know I know epoxying the ebony (top and sides of FB) won't change the neck's tendencies to move. BUT>>>>the 64k question...Do you know if epoxy (not polyester or some hybrid resin) actually hermetically seals wood? The only real aim here, is to lock up the ebony. I don't mind the sound of epoxy...had it before. But I never paid attention to issues like this, back then. Now it's critical. Super low action, Colorado dryness, etc. Any experience and empirical observations here are real valuable. I'd also throw in CA glue, but preliminary research on this suggests it doesn't block moisture exchange as well as epoxy (appears to do, according to claims by manufacturers).
Ebony moves less than Maple, generally. So you may make the problem worse by epoxying just the fingerboard. If you do, the maple will continue to absorb/lose moisture while the ebony doesn't, creating a more stress on the fingerboard to neck joint. But if you were to epoxy both, the neck/fingerboard would be less prone to changes in humidity.
I would be more inclined to lightly sand the maple neck and re-seal it instead.
Not to get into a wood debate but don't most folks get ebony for tone? Coating in epoxy would kill that wouldn't it? Why not try a humidity stick like acoustic guitar players use.
I have two padauk necks with ebony fretboards, one is gaboon ebony, the other is macassar. They are both very stable necks. Neither is finished with anything so I wouldnt say a neck with an ebony board is prone to movement. It is just that individule neck, and any finish wont.change it.
The most appropos thing re; my inquiry is just the sealing properties of epoxy. We could all have a good natured debate about the sound of ebony. So many boneheads say wood doesn't matter, I can't believe it. The statement is laughable. (Nobody here has jumped in and said "You can't hear the effect of a fretboard!")
Thank god no one's going there. I love the attack and tone of ebony. But despite it's unchallenged position as the king of strings (upright, violin, cello, etc.), A lot of people with great ears and vast experience hold ebony to be more of a hassle in terms of expansion & contraction. At least one of them is practically worshipped... his name rhymes perfectly with "SADOWSKY." Besides, I've seen it myself. I have never seen any hardwoods crack, shrink or expand as rapidly as Ebonies do in Colorado. Hands down. i say "Ebonies," b/c I can't verify the source of what I have.
My tech has done thousands of instruments, and would back me up on the joys of shrinking, cracking, expanding ebony in a split second. Come to think of it, I had a 'Wick FNA Jazzman fretless 5, and it's ebony board expanded, shrunk and cracked. I had a 'Wick Thumb NT 5...same deal. My best friend had the same model; Thumb NT5...shrunk/expanded, cracked. And I seriously care for my instruments. so does my friend. Always have. Of course, everything takes a beating here at this elevation. That's why I'm hoping to move forward with nothing but Ovangkol necks. I love that stuff. Naturally, I'd want a quicker-responding fingerboard...Gee, ebony comes to mind!
I'm more than sure some of you have ebony slabs that are literally God's gift...(could you send some my way?) I just want to see if anyone here can say through experience and/ or real knowledge of the chemical properties of epoxy resin, if said resin acts as a humidity barrier. Obviously it's a slam dunk in keeping out gross amounts of water. BTW, I had a J-neck with Brazilian rosewood done...waiting for finishing. It will be a hoot to finally get my hands on Brazillian again, and see if it's really "the King of tonewoods," as so many have said.
Thanks for the ideas, guys.
Hey Hopkins, since you live in a swamp, and I'm in a high semi-arid burning dry hellhole, I wonder who's got it worse?
I'm from Colorado. We're the state that's on fire. Except now, when we're flooded.
I grew up in FL, but didn't understand low action back then, so I knew nothing of neck movement. Here, I can feel every change, what with winter lows of about 3% humidity, and occasional jaunts into the 60-70% range during monsoons twice a year. Sucks!
The only thing I have that's THAT stable is my FNA Jazzman 5 fretted. Probably 1-2 times a year to keep super low action. Everything else moves a bit or a lot. I usually unload the stuff that moves too much. I friggin' adjust my Taylor acoustic guitar about once a month, no lie. Ebony on Mahogany. I have done this particular Ebony J bass neck (it sounds great) about four times in the last two months. Again, raining 3 times a day- most unusual for Colorado Springs.
The short answer is yes, marine epoxy effectively encapsulates the wood, thus making it inert (for all intents and purposes); but the idea to do that to a FB only is...well...
Let's put it this way, in order for the epoxy to properly provide the desired results, it would need to be on the order of 3/16"-1/4" thick- 1/8" bare minimum. I used this stuff for the better part of a decade, so I feel I can make this assertion. For real-world evidence, look to the tables at a lot family-type restaurants or even bars that have the crushed peanuts or coins or what-have-you in the table under a thick coat of plastic- that's typically epoxy resin.
Are there some epoxies that require a thinner coat? Of course, but they won't do what you're asking either. I rarely chime in on this stuff, but for some reason, I felt the need to.
1) Select any hardwood board.
2) Seal one side with epoxy or another non-permeable sealing coat.
3) Expose it to humidity
Over time, the side of the board which is NOT sealed will expand, and the board will warp/cup, bending toward the sealed side.
The student is left to interpret this experiment in terms of its effects on a fingerboard.
I've only ever epoxied rosewood, and that was for tonal reasons, and so roundwound strings wouldn't beat up the rosewood. I don't think I would to that to ebony unless I wanted a mirror finish on it, though.
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