Tenon exanpsion--need help

[Akiba]

The main tenon between the headjoint and body expands as I play due to moisture build up. Thus, the fit is loose to begin with and then gets tighter as I play.

I did some research in the C&F archive and found this is a bad thing to be happening. I read there is not much permanent I can do about it except send it back to the maker or to a repair person to get the bore fully sealed.

Anyone have any other suggestions?

Thanks,

Jason

[Sillydill]

Hey Jason,

Clean the end of the tennon with alcohol or acetone. After that dries, paint the end with super-glue. DO NOT ASSEMBLE YOUR FLUTE TILL THE GLUE DRIES!

Then I bet you won't have the problem anymore!

Very little moisture travels laterally through the wood. But capillary action will really wick it up into the wood (longitudinally). Your flute wants to drink, just like when it was a tree. But don't let it.

[Akiba]

Hey Jason,

Clean the end of the tennon with alcohol or acetone. After that dries, paint the end with super-glue. DO NOT ASSEMBLE YOUR FLUTE TILL THE GLUE DRIES!

Then I bet you won't have the problem anymore!

Very little moisture travels laterally through the wood. But capillary action will really wick it up into the wood (longitudinally). Your flute wants to drink, just like when it was a tree. But don't let it.

I'll try it.

THX

j

[Rob Sharer]

Boy, I sure would check with the maker before taking a step like this. I'm also not too sure about the assertion that little moisture travels through the thin wall of the tenon from the bore, especially if the flute is made of more porous wood.

I'd say the first things to try are:

1) Swab your flute more often.

2) When the flute is completely dry, i.e. first thing in the morning, put some cork grease on your finger and rub it into the inside wall of the tenon (got this idea from Pat Olwell, no less). This might prevent too much moisture from migrating. Didn't see you say whether you have corks or thread, but if it's corks maybe grease them more thoroughly. I'm not very experienced with thread but maybe it's a similar thing.

3) Don't keep the flute assembled when not playing. At the very least, leve the joints halfway together, to let the cork/thread dry.

I'd start with all of this stuff before resorting to something as drastic as glue-sizing the endgrain of the tenon. Cheers,

Rob

[Cathy Wilde]

I THOUGHT I had that very problem with my boxwood Olwell. So recently, after a year or two of slathering the joints with cork grease before playing and gritting my teeth when it was time to take it apart, I sent the flute off to have the tenon ends sanded down.

However, it turned out it was the flute's SOCKETS that had somehow morphed a bit -- the tube at those points had become sort of reverse-hourglass-shaped, wider in the middles than the ends (every tenon! Isn't that weird?) -- so when I put the flute together dry it was rattly and loose in the middles of the joints but after I played for an hour or two they'd be stuck together like they were glued.

Heaps and heaps of credit to David Copley for spotting the real issue and doing a wondrous repair job; the tenons and sockets are all at peace once more and the flute is playing better than it ever has.

This isn't telling you what to do or not do, but it might be worth your while to consult a repairer, if nothing else, for another perspective.

[Akiba]

Boy, I sure would check with the maker before taking a step like this. I'm also not too sure about the assertion that little moisture travels through the thin wall of the tenon from the bore, especially if the flute is made of more porous wood.

I'd say the first things to try are:

1) Swab your flute more often.

2) When the flute is completely dry, i.e. first thing in the morning, put some cork grease on your finger and rub it into the inside wall of the tenon (got this idea from Pat Olwell, no less). This might prevent too much moisture from migrating. Didn't see you say whether you have corks or thread, but if it's corks maybe grease them more thoroughly. I'm not very experienced with thread but maybe it's a similar thing.

3) Don't keep the flute assembled when not playing. At the very least, leve the joints halfway together, to let the cork/thread dry.

I'd start with all of this stuff before resorting to something as drastic as glue-sizing the endgrain of the tenon. Cheers,

Rob

Thanks for the heads up, Rob. I'll try your less drastic measures first.

Great to hear from you as well. Seems it's been awhile since I've seen you on the board. I value your input around here (well, most of the time...).

j

[Denny]

First, I agree with Rob's numerated points.

However I am not convinced that he and I are reading Jordan's suggestion the same way. I think that Jordan was speaking of the end grain. (The end of the tendon and not the body of the tendon. That doesn't help much..... The part that was cut with a saw, not the part that needed a lathe)

Cork or thread both work the same for this topic.
The end grain of the tendon will not be affected by the cork/thread as the moisture will reach it first.
The "glue-sizing" comment also makes me wonder if we are thinking of the same thing.

Next time the flute is dry grease the end well before putting it together and see if it helps. What Jordon suggested is sealing the end grain.

[Rob Sharer]

First, I agree with Rob's numerated points.

However I am not convinced that he and I are reading Jordan's suggestion the same way. I think that Jordan was speaking of the end grain. (The end of the tendon and not the body of the tendon. That doesn't help much..... The part that was cut with a saw, not the part that needed a lathe)

Cork or thread both work the same for this topic.
The end grain of the tendon will not be affected by the cork/thread as the moisture will reach it first.
The "glue-sizing" comment also makes me wonder if we are thinking of the same thing.

Next time the flute is dry grease the end well before putting it together and see if it helps. What Jordon suggested is sealing the end grain.

No, I got the part about the end grain. I'm saying that's not the only part of the wood likely to soak up moisture. For what it's worth, I do try to bang extra cork grease into the end grain of the tenon as I grease things up, but why stop there? Might as well swirl some around in the tenon part of the bore while you're at it. I'm not sure anyone can say with certainty what part of the tenon will see moisture first, or whether that's even the most important thing, or whether cork or thread passes/holds more moisture (...Terry?). I'm all for trying to exclude moisture from this most sensitive part of the flute body, but it just seems a bit drastic to go sizing the end grain with superglue, especially without consulting the maker first.

Once, when I spent a few days in a very damp self-catering cottage in Wicklow, I observed two interesting phenomena: 1) it actually rained in the bathroom after a shower, and 2) the main tenon on my Olwell swelled to the point where the wood was making contact with the wood of the socket and preventing the flute from going together. Bloody Ireland!

Cheers,

Rob

[crookedtune]

After a couple of years of playing my (already pre-owned) Casey Burns standard, I sent it back to the maker for a tune-up. It came back yesterday, better than I got it.

Casey smoothed the bore, re-threaded the tenons, and used commercial bore oil on the inside, as well as very liberal amounts of cork grease on the threads. I think that the cork grease applied to the open-grain area on the ends would certainly keep the flute from "drinking". It hasn't had that effect on me, though.

[Denny]

Okay Rob, just wonderin'

[Sillydill]

Hey Jason,

I presume you're having this problem with your newly aquired Burns Mopane Rudall.

Casey now paints the ends of his tennons with varnish, to seal the end- grains and prevent this problem.

The super-glue provides a harder and thinner finish. It is fairly easy to remove with acetone.

[Rob Sharer]

Hang on. Cured superglue does not always remove with acetone, especially when it's in the grain of the wood. To the contrary, it's damn tenacious when cured, well nigh impossible to shift. Varnish would soak out with alcohol. Caution!

Rob

p.s. This need a bit of clarification...

You can indeed use acetone to remove superglue in certain circumstances; I personally would despair of tryng to use it to soak glue out of end-grain. Also keep in mind that acetone will drive oil/resins out of the wood itself. Cheers,

Rob

[Jon C.]

I have done this on problem blackwood tenons, that swell up like this. If the CA glue doesn't do it, I have to turn a little off the tenon. If there is a gap where the socket is longer then the tenon, water will tend to wick into the tenon joint. You can check this with calipers. The socket can get out of round, like Cathy mentioned, and cause binding, then the socket would need to be re-bored.

[Guinness]

...The end of the tendon and not the body of the tendon...

I love Vietnamese pho, even the chewy parts. Mmm...

[Denny]

quit that!