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Cocobolo questions.
http://www-.luthiersforum.com/forum/viewtopic.php?f=10102&t=5367		 Page 1 of 2
Author:  Steve Saville [ Tue Feb 28, 2006 2:55 pm ]
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I understand cocobolo is a bit oily. How do you handle bonding and finishing? Do you wipe with a solvent before bonding? Do you only use epoxy, HHG, or is LMI white glue OK?
Are there some tips for finishing? Does the oil cause incomplete or very slow cure of certain finishes?
Any other important tips for working with this wood? I know some are very allergic to it and it is best to wear a mask and even gloves if needed.
Author:  Bruce Dickey [ Tue Feb 28, 2006 3:55 pm ]
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Some people should never touch the stuff. I'm not one of them. It burns the skin, eyes, nose, and between the toes. I know.

I highly recommend working it mostly outdoors if possible to keep the dust from ever getting into your work area. Never, even think about sanding without full protection for your lungs.

I use really good dust masks, but a half face respirator is not out of the question with this stuff.

As far as gluing, I have used Titebond with no problem whatsoever gluing cocobolo. I love cocobolo because it is extravagantly beautiful, especially when finished.

Others recommend wiping with acetone, but don't do that myself. It hasn't been a problem with Titebond Original. You know it's oily when it cakes a set of sandpaper on a drum sander in four passes. Again, there are those who use other glues, never tried them so I'm no help.



here is one going together with a four piece back



Here is a Grand Auditorium I built. Again, Titebond Yellow Original is what I've used so far on cocobolo.

Don't chance it, clean your shop well and use a mask. I was sick six months with a coco induced respiratory illness. Toxic stuff.
Author:  Daniel M [ Tue Feb 28, 2006 7:30 pm ]
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Thanks for the warning Bruce! I'm planning on using Coco on the next build. I thicknessed a set for a friend recently with no adverse effects, so I'm pretty sure I'm not alergic.
It is good to know about the toxicity & act accordingly.
Author:  A Peebels [ Tue Feb 28, 2006 10:15 pm ]
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I resawed a drop top of cocobolo recently. The dust has a really nice smell,so don't be fooled. It can really be dangerous. As bruce said, it is really oily, and wrecks sandpaper quickly. I used a planer to dress my tops. Tightbond works fine, and the beauty of the wood makes it worthwhile.

Al
Author:  LanceK [ Tue Feb 28, 2006 10:28 pm ]
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I always wipe the area to be glued to with a rag damp with asetone. After a couple of pass the wood stops leaching the oils, if only for a while.
I did have a brace pop off after using LMI white, after a close look it appeared to be the fault of the gluer no the glue I may have starved it a tad.

Some people bake there coco in the oven at around 250* for a couple of hours to get the oils to bake out, Ill be trying this on my next coco guitar coming up.

Oh, and what everyone else said, dont breath the stuff!
Author:  Bruce Dickey [ Wed Mar 01, 2006 1:11 am ]
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I have no idea if this is true. This glue and cocobolo question surfaces somewhat frequently. And it seems each time it does so does the recommendation to wipe wood with acetone.

Along about the same time.... comes the mention of failed joints. Putting two and two together..... is there a relationship?

Knock on wood, I've never had any glue joint separate with Titebond Original. The added note: Never, have I ever, swiped wood with acetone before gluing.

I just prepare the cocojoint like any other and glue. I agree with Lance, a starved joint is a weak one and could have caused that joint to fail. But it also had acetone in the mix, now didn't it. Something to think about as we start the day.
Author:  Josh H [ Wed Mar 01, 2006 1:39 am ]
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I know a lot of guys who do what Lance and other are doing by wiping the joint first and it works fine. But I once had someone tell me that while the acetone temporarily removes the oils it causes something like a vacuum. More oils then rush to the area where the oils have been removed causing a greater concentration of oils than there were there before.

Maybe I'm out to lunch on this one , but it kinda makes sense (to me at least). I glue the back joint and blocks with epoxy designed for use on oily woods. The rest is done with the normal glues. I know of others besides Bruce who use the regular titebond and have never had a problem.

There seem to be a number of ways to skin this cat. And I think they all work.

Josh
Author:  LanceK [ Wed Mar 01, 2006 1:53 am ]
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Bruce-
The acetone was completly evaporated.
I really do think I just didnt have enough glue or clamped it to tightly.
Author:  Tom Armstrong [ Wed Mar 01, 2006 2:25 am ]
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I'm in the middle of a Ziricote build right now, my first attempt with this wood. It also extremely resinous (oily). Any concers with PVA adhesion with this wood that should cause me heartburn?
Author:  Don Williams [ Wed Mar 01, 2006 2:42 am ]
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I would not hesitate to say don't use titebond on cocobolo. I've had, and heard of issues with creeping of the joint. I would recommend something more along the lines of an epoxy than wood glue. Someone once told me about an epoxy made specifically for oily woods. I would hunt it down and use it.

My problem specifically was that the joint creeped and caused adhesion issues with the finish at the joint. I refinished and it happened again. I refinished AGAIN and it happened again. Finally took the back off and reglued the seam with something else which worked. Can't remember what. But it wasn't Titebond...
Author:  Steve Saville [ Wed Mar 01, 2006 2:57 am ]
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What about high figure? Is there any thoughts about stability and tone vs. figure? Is the less figured stuff more stable and because it is closer to 1/4 sawn better tonally?

I did go out to my shop and sand some coco and wipe it on my hands and sniff it. Stupid act? Sure, but I'm used to that! I think it did tell me that I can work with it without a serious reaction. I will use a mask when I work with it.
Author:  Mattia Valente [ Wed Mar 01, 2006 3:06 am ]
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Don, I think you're thinking of Smith All-Wood epoxy. LMI carries it. It ain't cheap, though...
Author:  LanceK [ Wed Mar 01, 2006 3:12 am ]
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From what I understand, Coco is something that if you dont already have a reaction to it, you will the more you use it. People develope a sensitivity to it. I think Mario could explain this better than I.
Author:  Don Williams [ Wed Mar 01, 2006 3:14 am ]
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Mattia...that could be. I'm also wondering about polyurethane glue. It seems to be epoxy-like in it's hardness, and in theory won't creep. Not an expert by any means on that stuff though. It could be worth a try.

Tom Gasawdust,...I've never had "oily" ziricote before. Interesting.
Author:  Brock Poling [ Wed Mar 01, 2006 3:49 am ]
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[QUOTE=Mattia Valente] Don, I think you're thinking of Smith All-Wood epoxy. LMI carries it. It ain't cheap, though...[/QUOTE]

I have used this before, it is very nice glue.

I have never had a problem with cocobolo and titebond, or cocobolo and LMI white either.
Author:  Josh H [ Wed Mar 01, 2006 4:12 am ]
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Don

Lee Valley caries an epoxy for oily woods. I have used it on a number of builds and it works great.

josh
Author:  Howard Klepper [ Wed Mar 01, 2006 4:38 am ]
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Um, Bruce, doesn't the decorative strip go on the outside?
Author:  Jimmy Caldwell [ Wed Mar 01, 2006 4:46 am ]
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The only thing I do differently on cocobolo guitars is use the all-wood epoxy on the center seam of the back. Other than that, I treat it just like any other wood.

No problems so far, knock on cocobolo.
Author:  arvey [ Wed Mar 01, 2006 4:57 am ]
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I treat coco like any other wood. Tried Wipeing once and the hide glue centre joint failed. I think it was Mario who told me that Acetone actually draws out the oils so can make it worse. Since then I joint the edge and glue ASAP. Works great so far.
Author:  csullivan [ Wed Mar 01, 2006 4:58 am ]
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polyurethane glue is a perfect application for oily woods. It's excellent for
back seams and glueing the back to the rim. And no creep.
Craig
Author:  Bruce Dickey [ Wed Mar 01, 2006 6:27 am ]
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Howard, I like mine on the inside. Actually I'm a slap-it-in-the-sandwich kind of guy. Also I have a little trademark dead center of every soundhole. Like this:



That way you get to see that the marquetry is solid through and through, not a decal. The one you see in the second pic hasn't had the graft applied yet. Sometimes I chisel it off, other times I piece it in.
Author:  Kim [ Wed Mar 01, 2006 6:55 am ]
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Nice touch Bruce.

Kim
Author:  Serge Poirier [ Wed Mar 01, 2006 8:56 am ]
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An engineer we have in you Bruce!
Author:  CarltonM [ Wed Mar 01, 2006 10:59 am ]
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As Lance mentioned, adverse reaction to a substance is often cumulative, rather than immediate. You may have heard, for instance, of people who develop sudden allergies to shellfish after having eaten it for years without any problem; or, of someone who became allergic to bee venom only after having been stung more than once. Exotic (and some domestic) woods often carry natural poisons to keep the beasties from eating it. We're just a higher order of beastie, and though we don't eat cocobolo (even sounds tasty, doesn't it?), those chemicals can get us, too.

Thanks to Bruce for the reminder. I've got some coco. fingerboards that I'll be using, and it's always good to think seriously before rolling around unprotected in potentially toxic dust.
Author:  Serge Poirier [ Wed Mar 01, 2006 1:50 pm ]
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Thanks for the explanations above Carlton, i agree completely that all woods can be nasty to our lungs if we don't use every precaution to protect ourselves from breathing the fine particles emanating from our activities.
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