First of all I want to apologise for asking this question that has close relation to repairing wood cracks with cyanoacrylate (CA) on clarinets but it is not solely about clarinets. Forgive me and if the moderator will be generous enough to keep my thread alive I appreciate it.
Once again this is closely related to the subject of CA crack repairs on clarinets but is more of a general nature. I hope someone with deeper knowledge of the subject will demistify the very nature of this repair. In other words: why does it *actually* work?
So, first let's assume we have a crack in the clarinet body (I'll expand this later to one other use that I'm at the moment very concerned about so please bear with me).
There are a number of threads on SOTW and elsewhere about the procedure of how to apply the CA to the crack, well it's simple enough. Once the crack is filled and the CA cures many report that the crack never opens afterwards. More sceptical repairers insist on pinning but the first group insists that CA is all that is needed to keep the crack from further opening up. Let's leave that argument to another thread (actually I remember there was already such a thread on SOTW or elsewhere).
So, now to the subject of my question and again sorry for such a long preamble!
When the clarinet crack is filled with the CA does CA act more like a glue or more like a filler with glueing capabilities or... maybe a glue with filling capabilities?
Why the question? I don't know what force in terms of psi is being applied to the glued (or filled?) crack by the wood when it wants to open up the crack again but I assume that it's powerful enough since even pinned cracks sometimes open up. So, is it glue then?
Now, let's expand the area of application a little to get even closer to the subject.
Assume you have a piece of wood that is cracked along the fibers in half but it's not one piece with a crack in this case but you have two separate parts that you need to glue together.
Assume also that you have only two "glues" as a choice for the puropse of this discussion:
- very popular among woodworkers Titebond and
- our favourite friend the CA
Can you achieve similar results in terms of strength when restoring the integrity of that piece of wood when using either of the two glues? Here I don't know how to clarify my question to explain what I mean exactly. However in this particular case I doubt anyone would get an idea to use CA for this purpose. I think it's the last choice someone would make for such a repair.
But why? Won't it make the strong enough bond of the two wood pieces in comparison to the CA-filled crack on the clarinet?
So, re-arranging the question the other way round: if you had the clarinet completely split in two halves along the length would you use Titebond to glue two parts together instead of CA?
Now, please explain to me how CA *actually* works in application to wood. Is the repaired crack strong as much as the CA layer itself? What I mean by that: assuming the CA penetrates into the wood surface on both sides of the crack and grips the wood grain firmly enough what force one needs to apply to break that joint?
In other words in this case when strong enough crack opening force is applied will the CA-to-wood link break or will the CA layer itself break?
I also want to note that in the case of "glueing" two separate wood pieces together when using Titebond clamping would be required but with CA I never hear about clamping regardless of whatever repairs are done with it.
Also I've read that the CA is useless in the attempt of glueing two different wood parts together: it won't work because the two different parts cannot be joined together close enough. Actually that's why I used an example of the wood piece split into two separate halves: they would perfectly meet for CA application.
But, wait... when you are glueing or... filling? the clarinet crack aren't the walls of the crack far enough apart from each other to take their matching surface into consideration at all?
So, back again: is it filler or glue in this case? Why does it work to bond the two clarinet crack walls that are quite far enough from each other and doesn't works at all for bonding two separate pieces of wood accordng to the warning I've read even when you use clamping which would actually force the two pieces of wood close to each other?
And now... I want you to help me with the following provided you've read up to this point - hope someone is still with me
I have a lute pegbox that has a hairline crack that goes into the peg hole. The crack is closed and tight and is a result of the shipping accident. It looks like at this point it does not present much of a problem but I want to repair it and make the crack glued or... filled with CA?
Please refer to the picture (it's actually a wood crack that goes all the way through, not simply a finish crack I can open it up a bit). The pegbox wall thickness is about 7 mm. Your answer will help me to make a decision whether to use CA for this purpose or use something else. Why CA? Because I can temporary open-up the crack with a "taper" a little and run CA into the crack. No other glue will do that. Then I remove the "taper", the crack closes itself and stays glued or... filled? How strong will be such crack repair?
In other words at this point you probably understand the purpose of my treatise above. How strong will be the crack joint repaired with CA provided the peg opening action is applied in normal way?
Compare it to the clarinet crack repaired almost in the same manner provided the similar psi is applied to the clarinet crack under the crack opening force. I assume the force that is applied to the clarinet crack glued or... filled? with CA is well comparable to the peg applied to the peg hole.
In both cases with the clarinet crack and the pegbox crack the cracks will be under some constant load.
So, what do you think? Will such a repair hold up on the pegbox?
Thank you for reading if you got this far.
Once again this is closely related to the subject of CA crack repairs on clarinets but is more of a general nature. I hope someone with deeper knowledge of the subject will demistify the very nature of this repair. In other words: why does it *actually* work?
So, first let's assume we have a crack in the clarinet body (I'll expand this later to one other use that I'm at the moment very concerned about so please bear with me).
There are a number of threads on SOTW and elsewhere about the procedure of how to apply the CA to the crack, well it's simple enough. Once the crack is filled and the CA cures many report that the crack never opens afterwards. More sceptical repairers insist on pinning but the first group insists that CA is all that is needed to keep the crack from further opening up. Let's leave that argument to another thread (actually I remember there was already such a thread on SOTW or elsewhere).
So, now to the subject of my question and again sorry for such a long preamble!
When the clarinet crack is filled with the CA does CA act more like a glue or more like a filler with glueing capabilities or... maybe a glue with filling capabilities?
Why the question? I don't know what force in terms of psi is being applied to the glued (or filled?) crack by the wood when it wants to open up the crack again but I assume that it's powerful enough since even pinned cracks sometimes open up. So, is it glue then?
Now, let's expand the area of application a little to get even closer to the subject.
Assume you have a piece of wood that is cracked along the fibers in half but it's not one piece with a crack in this case but you have two separate parts that you need to glue together.
Assume also that you have only two "glues" as a choice for the puropse of this discussion:
- very popular among woodworkers Titebond and
- our favourite friend the CA
Can you achieve similar results in terms of strength when restoring the integrity of that piece of wood when using either of the two glues? Here I don't know how to clarify my question to explain what I mean exactly. However in this particular case I doubt anyone would get an idea to use CA for this purpose. I think it's the last choice someone would make for such a repair.
But why? Won't it make the strong enough bond of the two wood pieces in comparison to the CA-filled crack on the clarinet?
So, re-arranging the question the other way round: if you had the clarinet completely split in two halves along the length would you use Titebond to glue two parts together instead of CA?
Now, please explain to me how CA *actually* works in application to wood. Is the repaired crack strong as much as the CA layer itself? What I mean by that: assuming the CA penetrates into the wood surface on both sides of the crack and grips the wood grain firmly enough what force one needs to apply to break that joint?
In other words in this case when strong enough crack opening force is applied will the CA-to-wood link break or will the CA layer itself break?
I also want to note that in the case of "glueing" two separate wood pieces together when using Titebond clamping would be required but with CA I never hear about clamping regardless of whatever repairs are done with it.
Also I've read that the CA is useless in the attempt of glueing two different wood parts together: it won't work because the two different parts cannot be joined together close enough. Actually that's why I used an example of the wood piece split into two separate halves: they would perfectly meet for CA application.
But, wait... when you are glueing or... filling? the clarinet crack aren't the walls of the crack far enough apart from each other to take their matching surface into consideration at all?
So, back again: is it filler or glue in this case? Why does it work to bond the two clarinet crack walls that are quite far enough from each other and doesn't works at all for bonding two separate pieces of wood accordng to the warning I've read even when you use clamping which would actually force the two pieces of wood close to each other?
And now... I want you to help me with the following provided you've read up to this point - hope someone is still with me
I have a lute pegbox that has a hairline crack that goes into the peg hole. The crack is closed and tight and is a result of the shipping accident. It looks like at this point it does not present much of a problem but I want to repair it and make the crack glued or... filled with CA?
Please refer to the picture (it's actually a wood crack that goes all the way through, not simply a finish crack I can open it up a bit). The pegbox wall thickness is about 7 mm. Your answer will help me to make a decision whether to use CA for this purpose or use something else. Why CA? Because I can temporary open-up the crack with a "taper" a little and run CA into the crack. No other glue will do that. Then I remove the "taper", the crack closes itself and stays glued or... filled? How strong will be such crack repair?
In other words at this point you probably understand the purpose of my treatise above. How strong will be the crack joint repaired with CA provided the peg opening action is applied in normal way?
Compare it to the clarinet crack repaired almost in the same manner provided the similar psi is applied to the clarinet crack under the crack opening force. I assume the force that is applied to the clarinet crack glued or... filled? with CA is well comparable to the peg applied to the peg hole.
In both cases with the clarinet crack and the pegbox crack the cracks will be under some constant load.
So, what do you think? Will such a repair hold up on the pegbox?
Thank you for reading if you got this far.