Hmmm, Dr. Andy came along while I wasn't looking.
Ron
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| Experiences gluing cocobolo (again) http://www-.luthiersforum.com/forum/viewtopic.php?f=10102&t=11014 |
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| Author: | John K [ Mon Feb 19, 2007 2:08 pm ] |
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I thought I would pass this along to the bretherin. It may prove beneficial. I have a cocobolo guitar I am building and I decided to use hot hide glue on the back braces because I have heard that hot hide glue works on cocobolo. I did clean the back with acetone very well, and when done with that the surface looked oil free and lighter in color. (a lot of color came off on the cleaning rag) After this dried thoroughly, I glued the braces down in the usual fashion and let it dry for about a week while I built other things. When I got ready to use the back I tested the back brace joint by flexing the back gently. All the braces popped right off. So, I am reaching for the super glue, because, as my brother says, super glue can glue butter to air. |
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| Author: | Brock Poling [ Mon Feb 19, 2007 2:13 pm ] |
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epoxy here... |
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| Author: | Don Williams [ Mon Feb 19, 2007 2:20 pm ] |
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Epoxy, or perhaps poly glue. I don't trust CA glue long-term. |
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| Author: | JJ Donohue [ Mon Feb 19, 2007 2:53 pm ] |
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Bummer, John. Better to find out when you did rather than later. But it sure was nice of you to post the results and save others from a worse horror. I believe some others have glued Cocobolo...I'd be interested in their experiences. I have not used Coco yet but you sure have me wondering. I only partially remember a discussion stating that the use of acetone actually caused more oil to rise to the surface but can't remember all of the details. Brock...what epoxy are you using on Cocobolo? Do you also use the acetone prep? |
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| Author: | Andy Zimmerman [ Mon Feb 19, 2007 3:02 pm ] |
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Wow I have built 5 guitars with cocobolo and have used titebond for all of them. No problems yet |
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| Author: | old man [ Mon Feb 19, 2007 3:04 pm ] |
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Maybe Dr. Andy will come along. He's done several coco geetars. Give us your procedure doc. Ron |
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| Author: | TRein [ Mon Feb 19, 2007 3:05 pm ] |
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I have polled the various builders who have bought cocobolo from Hibdon about glues, from Kevin Ryan to Tony Vines. The results are interesting: No body washes the surface first with any solvents and everybody uses Titebond. Tony said he leaves the clamps on overnight, but that is the only precaution he takes. I have never used cocobolo so I can't comment from experience. I am just passing along some info I have accumulated from some experienced builders. |
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| Author: | old man [ Mon Feb 19, 2007 3:08 pm ] |
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Hmmm, Dr. Andy came along while I wasn't looking.
Ron |
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| Author: | JJ Donohue [ Mon Feb 19, 2007 3:22 pm ] |
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Andy...did you use Acetone first? |
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| Author: | LanceK [ Mon Feb 19, 2007 3:23 pm ] |
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John, I have had great success with West systems epoxy. ANYTHING else and I've had popped braces. I have also heard that if you bake the backs prior to gluing them that regular poly glues will work fine. I've never tried this, but this advise came directly to me from a very formidable builder. JJ, I don't know what Brock does, but I don't prep the coco in any way before gluing with West Systems Epoxy. I do wipe the squeeze out with DA and a rag. Warning! DA makes COCO bleed like a stuck pig! So its a good idea to do your center seam reinforcement AFTER you glue on your back braces. Don't ask me how I know this. |
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| Author: | Brock Poling [ Mon Feb 19, 2007 5:25 pm ] |
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[QUOTE=JJ Donohue]Brock...what epoxy are you using on Cocobolo? Do you also use the acetone prep?[/QUOTE] I am using West Systems 105 resin and 205 hardener. No acetone prep. A rag damp with denatured alcohol cleans it up. One thing to watch is if you use too much DA you may get some bleeding of the coco color onto the spruce. It appears that using less DA on your clean up rag eliminates this problem. Coco is a fantastic wood though... really one of my favorites. |
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| Author: | letseatpaste [ Tue Feb 20, 2007 12:26 am ] |
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I'm a noob, but my first one which is still in slow progress (the box has been together at least a year) is cocobolo. I haven't had any problems with it yet. I probably used naphtha to clean the sawdust off the surface, but not enough to drag a lot of color out for sure. I used Titebond Original and haven't had any problems so far. I wonder if using a lot of solvent draws the oil to the surface too much. |
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| Author: | Dave Rector [ Tue Feb 20, 2007 1:02 am ] |
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On the only coco guitar I've built I used Titebond and, based on a recomendation by Mario, didn't wipe down the surface with solvent of any kind. It is still holding up fine after approx two years. |
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| Author: | John K [ Tue Feb 20, 2007 2:07 am ] |
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I think you guys are right about tightbond. I believe that it does adhere to the cocobolo pretty well. The lining of this guitar is put on with tightbond and seems to be stuck pretty well. I have no experience with LMI white glue on cocobolo but I bet behaves in a similar fashion. |
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| Author: | LanceK [ Tue Feb 20, 2007 2:21 am ] |
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John, I have had simular problems with LMI white. I swear by the epoxy for Coco. |
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| Author: | Bruce Dickey [ Tue Feb 20, 2007 2:30 am ] |
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3 Cocobolo guitars, all fine. Titebond. No wipy with acetone. Sorry John. Better to find out now. I wonder why titebond is better than hide, I really do. Where's Tim McKnight? 
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| Author: | Andy Zimmerman [ Tue Feb 20, 2007 3:56 am ] |
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With my 5, I just used tightbond. No wiping with acetone or any other solvents. Maybe in the trouble to get the glue to work, all the sovents used to make it work actually malke it worse |
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| Author: | Steve Saville [ Tue Feb 20, 2007 4:43 am ] |
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Just to give a little background, I've done cleaning validations for medical devices. We've investigated and spent more time thinking about, talking about, and experimenting with cleaning than you would believe. But you can believe that the stuff that we design and have processed is clean. We work on cleaning both the product and work surfaces. You'd be surprised how bad wiping is at cleaning. Most of the time it just smears stuff around without removing much. I seriously doubt that wiping with acetone or another solvent draws out any extra oil. I strongly suspect it just evenly coats the gluing surface with the oil that is already there. If you must wipe, do it in one direction only, like back to front. Change the cleaning pad surface with each wipe. Do not ever wipe in circular motions or back and forth. If you wipe in the same direction, with clean wipe surfaces, until the wipe does not remove any color, you would have a good clean surface to bond to. |
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| Author: | John K [ Tue Feb 20, 2007 4:55 am ] |
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Good advice Steve. In fact that is what I did. There was oil on the surface before I wiped, that much was certain and I doubt that it got oilier with attempts to clean. I wipe with acetone, change the pad, wipe again and do that until the color is no longer transfered to the pad. My thoughts are/were, that if the color is no longer transfering, there must be less oil than there was. I don't know how many of you ever read Art Overholtzer's book on guitar building but he actually washed Brazilian in hot soapy water, changing the bath until there was no more pitch left in the wash. His thought was that there was too much oily residue in the Brazilian to glue effectively. The guy did make great classical guitars, winning an international competition for one of his efforts. But imagine the trouble, and really I suspect it was all unnecessary. |
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| Author: | Steve Saville [ Tue Feb 20, 2007 5:18 am ] |
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John, I deal with smooth surfaces like stainless steel. As you know, wood does not qualify as smooth. I suspect that you got the easily reached areas clean. The pores and deeper sections that the glue adheres to and really gets its bond strength were very likely nicely coated with a very thin, even layer of oil. I've never gone through the thought process on this. I'm glad I did. Thank you for posting this. I've made up my mind to never try to clean oily wood like that before bonding. |
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| Author: | Bob Garrish [ Tue Feb 20, 2007 7:15 am ] |
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If I'm to believe the experience of others, Todd probably hit the nail on the head. There was much discussion on the MIMF about this and the consensus from the pros who used it regularly was that cocobolo glues fine but requires a fresh joint. Fresh as in plane it and then glue it right there. If the board had been left to sit for any length of time, then re-plane a fresh surface onto it. Wiping with solvents was highly unrecommended for some of the reasons others have mentioned (creates a nice thin layer of oil on everything). |
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| Author: | LanceK [ Tue Feb 20, 2007 7:27 am ] |
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I have had a freshly sanded back pop a brace using LMI white. I LOVE that glue and have moved back to using it for most everything I do, with the exception of gluing Cocobolo plates and braces to the plates. I cannot emphasize enough how well the west systems epoxy works for this application. It is rock solid after its dry. I just feel a sense of insurance with the epoxy over any other type of glue. |
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| Author: | John K [ Tue Feb 20, 2007 7:34 am ] |
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Lance I wonder if Titebond would bond any tighter than the LMI. I don't see any reason why it should but there is the experience of others that indicate that it might. I am with you on the epoxie. I have been using the allwood epoxie from LMI that they recommend for cocobolo and teak and other oily woods and it does a great job. It is a little pricey and I hate the cleanup but I guess that's the hidden cost of working with coco |
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| Author: | LanceK [ Tue Feb 20, 2007 8:08 am ] |
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John, One thing that I have noticed with Cocobolo is that no two sets are alike, unless there cut from the same board. I have five cocobolo guitars going right now and I think maybe two are close to the same "oil" factor 
The little 0-12 I did was very dry, by comparison one of my OMFS' I'm doing bleed like crazy! So I tend to think that what works for one set, may not work for the other. That is unless its epoxy 
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