Regarding Gluing up Cocobolo

Ray Holt · #1 01-07-2008, 07:10 PM

Hey guys, haven't been on here in a while, been keeping busy at Benedetto.

We're making a custom Benny right now with a Cocobolo top and some maple strips (well, they're tapered curves, pretty sweet). I'm sanding the body right now and got to chatting with Bob about it the other day, just picking his brain.

I had seen people on here about talking about having problems gluing cocobolo up because it's so oily, so I asked Bob if he had ever had this problem.

First of all, he said no. BUT, he said that if the wood is really oily and you're afraid it might cause problems, just rub the joint down with acetone and it will dry it out!

A lot of you might know this already, might be old news, but I had never heard someone with that trick before and wanted to share just in case.

That's it for now... I gotta pick his brain some more...

p.s. - Funny side note, Bob said the oiliest wood he has ever worked with was REAL Iron Wood. I forget the scientific name, but he said a lot of countries have "Iron wood" but there is one "real" iron wood. He said they used to use it to make ball-bearing for LOCOMOTIVES because it is so hard, and self-lubricating because it's so oily. He cut some on a band saw once and it was SHOOTING SPARKS!!! Isn't that awesome???

Jonsbasses · #2 01-07-2008, 07:21 PM

That is very awesome.

Yes, it seems to vary from piece to piece of Cocobolo, much like how every other piece of wood varies. I have purchased a board of Cocobolo that wasn't very oily, but my 3 most recent purchases have an insane amount of oil in them. I have heard many times "wipe it down with acetone", I'll avoid this advice until I personally have an issue gluing an oily piece of wood.

BassBilodeau · #3 01-07-2008, 07:55 PM

Quote:

Originally Posted by Ray Holt

p.s. - Funny side note, Bob said the oiliest wood he has ever worked with was REAL Iron Wood. I forget the scientific name, but he said a lot of countries have "Iron wood" but there is one "real" iron wood. He said they used to use it to make ball-bearing for LOCOMOTIVES because it is so hard, and self-lubricating because it's so oily. He cut some on a band saw once and it was SHOOTING SPARKS!!! Isn't that awesome???

Your talking about Lignum vitae, it's the densiest wood known, more than ebony. Here's a wikipedia link:
http://en.wikipedia.org/wiki/Lignum_vitae

By the way, ironwood is a commum term for "super-duper-hard-wood", there are no real or false ironwood.

Thanks for sharing about cocobolo by the way

Son of Magni · #4 01-07-2008, 08:55 PM

OT, but I remember getting sparks when cutting into endgrain of a big block of Beech, with... a chainsaw

erikbojerik · #5 01-07-2008, 11:28 PM

I have heard a thousand variations of this, and only two that seem to have a consensus about them:

#1 freshly sanded/scraped without wiping, glued with Titebond or polyurethane glue immediately after

#2 an "older" surface wiped down with acetone (keep wiping with fresh rags until you get to steady-state oil removal...), roughed up with 60 grit, then glued with Titebond or poly glue

By "older" I mean a surface that was planed/sanded/scraped so long ago that it is no longer bright red/orange, it has darkened due to exposure to the air (or is it UV?).

eleonn · #6 01-08-2008, 10:35 AM

Jonsbasses · #7 01-08-2008, 05:49 PM

Mostly UV, I think. I have some boards I have thickness sanded to 120 and sanded up to 220 and they still aren't purely red like what you'd typically see at the lumber yard. They have been no where near sunlight, although they have darkened up some. I'll see if I can get now pictures as I have pictures right after they were sanded.

Big B. · #8 01-13-2008, 01:36 PM

It's oxidation caused by moisture and air. Cocobolo will always turn darker red after it is cut whether it is exposed to light or not (same with purpleheart and paduak). cherry on the other hand will turn darker when exposed to light, so it must be stored with care or your boards can end up looking pretty funky.

Florida Jim · #9 05-09-2008, 07:45 PM

Hello everyone! This is my first post here. I've built a couple custom guitars and basses, and I'm starting a new custom 5-string bass. Fool that I am, I'm planning to make it out of all Cocobolo. It's sort of a neck-through design, in that the neck and center of the body are one piece with wings attached from the same plank. The piece I got has beautiful color and figure in it. There's a place here named Cocobolo inc., and he sells mostly this wood. I think it's a beautiful wood, and I think it will work out fine. I know it's a bit harder to make sure it's glued properly, but I'll do what it takes to get it done. I'll be asking a lot of questions about every aspect of building it, so will be talking with everyone again.

eleonn · #10 05-09-2008, 08:50 PM

Hi Jim... and welcome.

You are going to build a 5er and you are just going to use cocobolo. I would be a "bit" heavy.

barnaclebeau · #11 05-09-2008, 11:46 PM

In my somewhat limited experience, I haven't had a problem gluing cocobolo with titebond I after wiping it with acetone. My lignum vitae fingerboard is popping off though. That is some ornery crap. titebond, west system, and CA glue all equally suck at adhering to that stuff. BTW, lignum vitae doesn't spark. It's actually quite pleasant to work with edge tools, if you go slow. Had a WAY harder time with ziricote.

erikbojerik · #12 05-10-2008, 09:06 AM

I'd wipe it down, rough it up with 60 or 80 grit so you have scratches everywhere, then glue it up with Titebond or epoxy right away....like, complete all the steps within 15 minutes. Leave it under clamping pressure for 24 hours, then slowly (and uniformly) loosen all the clamps carefully. I'd be surprised if it popped after that.

Nelson Guitars · #13 05-10-2008, 09:34 AM

UV can create a photo chemical reaction in many woods. It is most noticeable in fresh cut material vs stuff that has been sitting around for a while. I have used some Cocobolo lately that when cut has distinct purple almost violet stripes with greenish blond between. Leave it out for even a day under shop lights and much of it goes away. Two or three weeks down the road and that nice Cocobolo color we all expect has returned.

I have never seen Lignum Vitae spark either. I have witnessed it in some Acacia though. We figured the tree had been growing in a high silica content soil. We could see white deposits in the exposed pores of the grain when cut. Dulled tools rather quickly.

Seems like I am always trying to prove or disprove these sorts of questions when they arise. A few years back I took some scrap pieces of Cocobolo and glued them up with various glues then tried to spit them with a wedge in my drill press. I had the blocks sitting on a bathroom scale to register at what point the joints broke. Pretty inconclusive because almost all of the joints broke on the wood adjacent and not the glue joint itself. It didn't matter if it was hide, elmers white, titebond, CA or 5 min epoxy. It didn't matter if the joint had been cleaned with acetone or not. The one glue that did fail was the one that is supposed to be the strongest glue in the world, Gorilla Glue (Polyurethane). When it failed I re-tested to make sure it wasn't something I had done. Failed again. I know people get passionate about their glues so please don't get up in arms about this. I am only reporting what my experience has been.

Greg N