 The Clarinet BBoard
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Author: klook
Date: 2010-10-05 21:44
I've seen a ton of info using cyanoacrylate glue for crack repair.
I myself have used it for filling cracks in clarinets that don't go through the bore.
I'm a very part time repair guy who does mostly old clarinets. Lotsa hard rubber and some wood.
Now I've got this old Penzel Mueller clarinet that has an old crack that was pinned previously but is now open again. It goes all the way through the bore and leaks air when I plug the holes and blow.
Has anyone had success with ONLY using cyanoacrylate for cracks through to the bore, or do I have to pin?
I've never done pinning before and I'm not afraid to learn, but if the glue might do the trick, why bother with such a time intensive and intrusive procedure?
Also, what of the old school method of getting hot wax into the crack? Does this ever work?
thanks!
mark
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Author: alanporter
Date: 2010-10-05 22:01
I have an old oboe with a full penetrating crack halfway around the bell. Superglue fixed it well.
tiaroa@shaw.ca
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Author: Chris P
Date: 2010-10-05 22:38
My first CT Bb has a crack in the top joint between the trill toneholes that goes through to the bore - it was filled (with superglue) and pinned and hasn't moved since done back in 1988.
I've superglued cracks on oboe and cor anglais tenons that have gone through the tenon and into the G# tonehole or round the side that have also gone through to the bore and these have held fast. Ditto with clarinet tenon cracks that have also gone through to the bore.
DO NOT USE HOT WAX! This will prevent glue adhering to the crack.
Former oboe finisher
Howarth of London
1998 - 2010
The opinions I express are my own.
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Author: jasperbay
Date: 2010-10-06 00:15
Superglue works fine without pins, although a wider crack will need grenadilla dust or thin slivers of wood added for strength (and the right color/texture) and to keep the thin glue from running all over the place! Using a flat-tipped toothpick to wick glue into the old pins, will add strength also. Pins were origonally needed before the advent of cyanoacylics, probably not needed nowadays, unless a crack is really severe.
I sometimes use paint remover to clean out old glue ( usually epoxy) that doesn't adhere to grenadilla wood very well. This seems to help the CA adhere to both sides of the crack. I seldom have to re-stain the wood, just re-oil after finish sanding/polishing. Actually, very few of the "blackwood" clarinets I've worked on are in fact stained. Staining seems to be used more on lower quality wood used on many newer clarinets.
Clark G. Sherwood
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Author: clarnibass
Date: 2010-10-06 05:01
Pinning started when glues were no where near good enough to hold cracks. This tradition stayed and many still think glue is not good enough because they never tried it properly without pins. When pinning is done with good super glue, it's entirely possible it is the glue that is doing most/all the work anyway.
The critical thing about gluing is the glue must contact the entire side and penetrate all the way. If you add wood dust before, the glue will soak into it and won't penetrate. So you have to use glue without wood dust at first and only add the wood (if you want) at the top.
Pinning alone obvioulsy won't seal a crack. There are several issues with pinning which, although don't happen a lot of the time, can happen sometimes. It's relatively destructive and risky. It's holding the body not so close to the top, not so efficient. Some claim it can help causing cracks in other areas. It sometimes doesn't hold the crack, I've seen properly pinned cracks re-open. I lose more and more hope in pinning and almost never do it now.
Another method is banding. Originally done at the edge with metal rings, now is also done with other materials. It's a bit more visual than pinning (circle around vs. just a few spots) but can look ok. It's most common to do with carbon fibers but that's a bit of a new tradition and I don't think many if anyone ever tried it with other materials (at least no one with an online presence). I intend to try it as IMO the carbon fibers have some disadvantages to working with them. This normally requires a lathe but can be done, if especially careful, without one.
So I would try glue only at first, only then move to other options. You have to make sure the crack is clean or the glue won't... glue.
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Author: klook
Date: 2010-10-06 21:00
Well I screwed up by putting some dust in the crack first. Then glue, then more dust. I'll have to see how it holds up!
klook
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Author: jasperbay
Date: 2010-10-06 22:14
I've tried it both ways, and prefer dust second (to ensure full crack penetration by the water-thin glue) but a light dusting first works almost as well. When filling dents, holes,etc., I've noticed that the CA will wick into the dust quite a ways, say 1/8", but the CA may not go past the dust 'dam' deeper into the crack.To ensure full crack penetration,you may want to dab some glue on both sides of the crack, by using a long thin screwdriver or whatever to apply some CA inside the bore. This will also help keep condensation out of the crack, but may require some tricky sanding to smooth up the bore afterwards.
Another thing I've noticed about thin CA, is that you have to keep adding a little dab, as long as the crack keeps sucking it in, sometimes several dabs over 10-20 secs. This occurs more on porous woods like walnut gunstocks, etc. but grenadilla does it too.
Clark G. Sherwood
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Author: Chris P
Date: 2010-10-07 04:44
On cracks through to the bore, be careful the superglue isn't running into and down the bore while you're filling the crack from the outside and it gets wicked in. Keep checking the bore as you go as cleaning hardened superglue from the bore can be a pain.
Former oboe finisher
Howarth of London
1998 - 2010
The opinions I express are my own.
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Author: clarnibass
Date: 2010-10-07 05:57
Maybe possible to make a non-stick plug to put inside the bore while filling the crack. For example a stick, maybe with a thin layer of foam over it and a teflon sheet glued over.
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Author: jasperbay
Date: 2010-10-07 14:24
Great minds think alike. I've tried teflon film, backed up by clay, to stop CA glue from running into the bore. It worked to a some degree, but the CA glue wicked to the extreme edge of the teflon film by capillary action. The best CA block I've come up with is masking tape or electricions tape.
Clark G. Sherwood
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Author: eac
Date: 2010-10-07 19:08
I saw some black CA medium viscosity listed on line once when I Googled superglue. Has anyone used it on grendilla?
I have a hairline crack through to the bore/flange in my bell. My teacher suggested I have it fixed but my technician didn't see the need or particulary want to do anything. So I've toyed with the idea of getting some of the black CA. The idea of blocking the CA with masking or electrical tape would certainly be easy on the bell. Any input from those who've done such repairs?
Thanks!
Liz Leckey
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Author: jasperbay
Date: 2010-10-07 21:48
You need the thin CA glue especially for hairline cracks. The medium will not wick into a fine crack like the thin will. Clear CA looks black (after fine sanding and polishing)when used on grenadilla , so black CA not really nessesary.
The tricky part for beginners is the thin stuff runs all over like water, especially when it squirts out of the container. I like to put a few drops in a tiny 'well' (1/4" hole drilled in metal or wax) , then dip and transfer with a flat tipped toothpick (sharpened like a wood chisel, or sharp screwdriver). Much more safe and controllable that way. It won't harden in the 'well' for as long as 5 minutes, I think open air inhibits the curing reaction. Good Luck!!
Clark G. Sherwood
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Author: clarnibass
Date: 2010-10-08 04:48
>> I've tried teflon film, backed up by clay, to stop CA glue from running into the bore. It worked to a some degree, but the CA glue wicked to the extreme edge of the teflon film by capillary action. <<
That's why I suggested a layer of foam. Maybe cork would work too, like a tenon, though I think I'd prefer the gentler push of foam. Clay doesn't flex like that and the idea was that it pushes towards the body slightly from the inside. Also possible to put some grease on the teflon, just a thin layer not enough to get into the crack but to seal even better. There should be no crack between the plug and body for the super glue to go through. I considered tape too but it could be tricky getting it inside if you want the glue side out, especially if the crack is deep. If the non-glue side out probably the same as teflon if put on a tenon-like stick.
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Author: Tony F
Date: 2010-10-08 06:32
When a friend repaired a crack in her bassoon with cyano-acrylate, on the advice of an experienced repairer she pushed a condom into the bore and inflated it. It worked well, there was no seepage into the bore, but she did get some seepage into a tone hole. It cleaned up easily and the bassoon has been in service for several years since the repair.
Tony F.
Tony F.
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Author: Chris P
Date: 2010-10-08 07:48
I also thought of balloons in the bore as they'll conform to the shape of the bore better once inflated - the best kind are probably the ones used for making balloon animals with as they're thin.
Former oboe finisher
Howarth of London
1998 - 2010
The opinions I express are my own.
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Author: Tony F
Date: 2010-10-09 07:19
There was a specific reason for using a condom rather than a balloon. I';m not certain after the course of several years, but I think it was to do with the quality of the material and its resistance to breakage.
Tony F.
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