 The Clarinet BBoard
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Author: saxlite
Date: 2008-02-14 14:12
I am repairing an E11 where a fingernail sized chunk of wood has raised adjacent to the thumb rest bracket. I have tried to glue this down with "crazy" glue and with carpenter's wood glue both with 24-hour clamping, but no luck- the piece just raises back up after the clamp is released. Could use some advice from the master technicians here- thanks!
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Author: David Spiegelthal ★2017
Date: 2008-02-14 19:25
Clean the surfaces to be bonded with acetone (or nail polish remover) to remove all traces of grime and oils) before you use any adhesives. I'd recommend epoxy first, then 'gel'-type "superglue" (cyanoacrylate) second. Don't waste your time with carpenter's wood glue.
With any adhesive bonding operation on any material, proper surface preparation is absolutely essential! The only thing 'superglue' sticks to without prep is your skin (ask me how I know........)
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Author: susieray
Date: 2008-02-14 21:30
Dave, I beg to differ, superglue also sticks quite well to a dirty kitchen floor, as evidenced by my husband's experience not too long ago. He was using superglue on his heel cracks, and set his foot down before the glue had dried........![[grin]](http://test.woodwind.org/clarinet/BBoard/smileys/smilie5.gif)
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Author: D
Date: 2008-02-14 21:50
my dad managed to glue his fingers together once. he cut them apart again with a razor blade. when i was five that was the best thing i had ever seen. he's the man!
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Author: Chris P
Date: 2008-02-14 22:51
If you can't get the raised piece of wood to stay down, leave it raised and completely fill the space beneath it with glue (epoxy or superglue), then put it aside for it to harden.
Then file the raised bit and the excess glue around it flush with the surrounding wood, paper it all smooth and polish it up to match the rest of the joint.
Former oboe finisher
Howarth of London
1998 - 2010
The opinions I express are my own.
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Author: doublej
Date: 2008-02-14 23:31
Dave - Chris or other techs
have you ever tried titebond III? I am just curious it has received great reviews for gluing up exotic woods even better than poly glues. The test I saw it on was Ipe (Brazilian walnut) very dense wood that does not glue well (test was in fine woodworking magazine). I have had great success with it on other woods but have not tried it on a clarinet.
JJ
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Author: Chris P
Date: 2008-02-14 23:52
I don't know what glue they're currently using in the factory to stick the metal socket liners on oboes and cors in with (they used shellac until recently), but it's pretty good stuff. Possibly some kind of epoxy.
I'll find out.
Former oboe finisher
Howarth of London
1998 - 2010
The opinions I express are my own.
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Author: Gordon (NZ)
Date: 2008-02-15 00:43
"... I have tried to glue this down with "crazy" glue and with carpenter's wood glue both with 24-hour clamping, but no luck- the piece just raises back up after the clamp is released. Could use some advice from the master technicians here- thanks!"
First, thorough cleaning is vital. If the timber surface is covered in an oily or greasy film, then you are only trying to stick the glue to that film. It doesn't work. The film will allow the glue to peel away.
"Dave, I beg to differ, superglue also sticks quite well to a dirty kitchen floor, as evidenced by my husband's experience not too long ago. He was using superglue on his heel cracks, and set his foot down before the glue had dried........"
The situation is quite different if the glue somehow has access past a surface film, to the underlying surface. So it all depends on what that film is, whether the glue's solvent allows the glue past it, etc.
Second, it sounds as if there is something providing quite a strong lifting force for this chip. You need to identify it and eliminate it. Perhaps the nearby timber has been stressed by a technician installing the thumb rest screw without tapping the timber to the correct thread. Perhaps there is a mess of non-matching splinters where the surfaces meet. Perhaps you now have a significant build up of dried adhesive over the surfaces. What CAUSED this chip to lift. You must deal with that cause, otherwise it will keep lifting.
Third. As already said, wood glue is next to useless on this timber. Now you have a layer of this glue over the surfaces. It must all be removed before you can hope for any success, otherwise it remains as a far-too-weak laminate.
4th. "I don't know what glue they're currently using in the factory to stick the metal socket liners on oboes and cors in with (they used shellac until recently), but it's pretty good stuff. Possibly some kind of epoxy."
That is a totally different application. It has a very large surface area, and the forces that need to be resisted are small, and a large amouint of SHEER would be involved to loosen it. Sheer is not involved with this chip. Most glues are far better in resisting sheer than they are in tension, peel, etc.
Chris's suggestion is good, now that that the surfaces can never match well because of the glue you already have on them. But you still need to first deal with whatever allowed/forced this chip off the body.
This is the sort of job that needs to be done right the first time. Now you really have to remove ALL the glue on those surfaces before carrying out a reliable, cosmetically-good fix, along Chris's lines.
Post Edited (2008-02-15 00:45)
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Author: saxlite
Date: 2008-02-15 18:25
Thanks for the good input, guys. I will try scraping out the old glues and flushing with acetone before attempting to reglue or fill with epoxy. To answer Gordon's "what caused this" question, the E11's adjustable thumb-rest screw was driven in too far, pressing against the body of the instrument and pulling up on the thumb-rest mount. This cracked the wood "north" of the mount. If cyanoacrelate glue doesn't do it, I'll try the "fill and sand" as the last resort. Stay tuned, I'll report the results. Again, thanks for all the good advice.
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Author: hans
Date: 2008-02-15 20:17
I don't use it often, but it's my understanding that cyanoacrylate bonds more effectively to damp surfaces. Be careful not to inhale it.
Hans
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Author: Ken Shaw ★2017
Date: 2008-02-15 21:32
Why did the wood rise up? If you push it back down, it will reintroduce the strain that caused it to split out in the first place.
If it split because the thumb rest was not anchored correctly, or because it was designed badly, or because there was a flaw in the wood, you want to find out and fix the source of the problem, not the symptom.
Ken Shaw
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Author: Chris P
Date: 2008-02-16 00:44
If you fill and finish as I previously mentioned, you might also need to drill and bush (with grenadilla dowels) the place where the thumbrest baseplate screws are to be screwed into as the wood and filler may not be strong enough (and also relocate the thumbrest baseplate about 10-15mm up the joint from where it is so you can get upward adjustment as well!), and also drill a blind hole beneath where the thumbrest adjusting screw is going to protrude from to avoid it ripping the thumbrest assembly up again once it's tightened.
Former oboe finisher
Howarth of London
1998 - 2010
The opinions I express are my own.
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Author: Gordon (NZ)
Date: 2008-02-16 07:33
"the E11's adjustable thumb-rest screw was driven in too far, pressing against the body of the instrument and pulling up on the thumb-rest mount. "
Do you mean not the mounting screws, but the screw that clamps the adjustable part? If so, make sure it cannot happen again.
If not, then there is something wrong with the way it was attached to the body. Tightening a mounting screw should not lift timber, unless the mount did not fit the timber properly.
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Author: saxlite
Date: 2008-02-23 17:28
After trying several approaches on an old cracked barrel, I elected to go with the "sand flush and fill" technique. I tried various wood fillers, shellac, etc, but eventually used JB Weld, a two part epoxy that leaves a dark grey color after sanding. I cleaned the surfaces with acetone, then put on enough JB Weld to cover with about 1-16th excess. After 24 hours of curing, I filed the surface smooth with a 1" fine file, then finish-sanded with crocus cloth to a perfect finish. Several coats of ebony wood stain darkened the epoxy to a color very near (but not quite) the surrounding wood. It looks good and seems to be very strong and secure. The screw that caused the original problem has been properly trimmed, so there will be no reoccurance. Thanks for all the good suggestions, guys!
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