I find that one of my tenons (dixon 3 piece poly) is a bit loose and how can I fix that?
Have considered using the teflon tape is that safe on this kind of tenons?
Any other suggestions?
berti
I have found that cork can recover it’s resilience if warmed gently - perhaps with a match.
Are you using cork grease?
Sometimes they just dry out and cork grease will solve the problem. 
Doc
First off, teflon tape won’t hurt a delrin flute at all…so feel free to use that. However, I’d bet cork grease per Doc, heat per Andrew, or even a soak in water for a few hours (just put the offending corked joint in a sink of cool water) will get it back in shape.
Eric
Hi Berti,
The cork is fairly easy to replace, if you need to replace it after putting a match to it! 
You might try steam.
You will need to get good quality cork sheet, .8mm/ 1/32" thick, and some good quality contact cement, or comercial cork cement.
I cut the cork with a paper cutter, cut the width to the right size, then wrap it around the tendon and cut the length, so it butts together nicely.
Apply glue to both surfaces, and allow to dry to a tack. Carefully wrap the cork around the tendon, without pulling it to tight. Allowing a little overlap on the butt joint is ok, as it can be trimmed and sanded. You want to avoid having a gap. Sand with fine sand paper, leaving the center a little thicker, to fit. Loren can give you a more detailed description. 
Jon
Would you purchase the cork at a home-improvement store, like Home Depot, or a craft store, like Michael’s?
Thanks.
Mary
Mary, most places sell composition cork which does not hold well under the pressure of use, I would order a piece from Ferree’s tools, (they may have a website), there phone number is 1 800 253-2261
best wishes, eilam.
I agree with Eilam, but as I recall (and I could be way off here) I think purchasing a single sheet of high quality cork is rather expensive (for some reason $18.00 sticks in my mind), so by the time you buy the cork, cement, and go to the trouble of dealing with it (Jon makes it SOUND easy 
) You’re probably better off getting it done by a professional. Not that I’m looking for more cork jobs mind you - after nearly two weeks of missed work, I’m buried in them at the moment!
Loren
Well Loren does make a good point,especially if you are just doing one or two tendons. It doesn’t seem to be that difficult… :roll:
I get the cork from Ferree’s 6’ x 12"@ $10.60
If you bought cork cement it has to be shipped ground, to the Netherlands that would be a slow boat! 
Beware of cheaper cork, I bought some from a instrument repair site, and the cork varied .8 mm to 1.2 mm! Farree’s has the best.
Jon
Jon wrote:
“It doesn’t seem to be that difficult… :roll:”
Nor does it seem that way to me, after about a thousand! 
Okay, to be honest it was easy after the first 100 or so 
Actually, we do ours a bit differently, so that plays in, but I was just thinking that for someone without the supplies at home, and without having done a few first, it might just be less of pain to have someone else do it. However perhaps I’m just feeling that way because I just spent a number of hours dicking with the wiring in my guitar because I needed to fix what some other knuckle head “Do it yourselfer” had done very wrong 
More power to those who want to learn to recork their own tenons, if you’ve got the time and energy, go for it. (Just take Eilam’s advice and don’t use that crappy composite cork.)
“I get the cork from Ferree’s 6’ x 12”@ $10.60"
Much cheaper than I remember, cool.
“Beware of cheaper cork, I bought some from a instrument repair site, and the cork varied .8 mm to 1.2 mm! Farree’s has the best.”
Amen brother, without a lathe to sand it concentric, that much variance will make you miserable.
Best,
Loren
Just thinking about getting it so there is no gap, then thinking about how to sand it concentrically without having a lathe, was enough for me to switch to thread instead of cork. Thread is easy to do and safe, although a little messier than cork.
The standard reference on how to do threaded tenons is here:
http://www.flutes.fsbusiness.co.uk/tenon.html
Most tenons made for cork work with thread just fine.
I’m probably just paranoid, but for cork, i wouldn’t even trust my local instrument repair shop; i’d send it back to the maker if possible, or send it to someone who does work in historical woodwinds, like Loren.
There you go with the thread lapping again Glauber Just kidding man 
I actually agree with you that if someone really wants to do it themselves, they will likely get a better result going with thread, as long as they make certain not to make the fit too tight. My only real gripe with thread lapping is that over the long haul it’s much more of a pain in the butt than a well done cork job, although to be honest, I don’t see many well done cork jobs 
FWIW, we don’t butt the ends of the cork flush together, we actually do a more involved process where the cork is overlapped, eliminating the possibility for dirt/grit to get between the seem, which is one of the main things that tends to make corks come apart/off prematurely.
Loren
That seems to be the Right Way to do it. I can’t imagine how you can do a “butt job” that would be perfect enough.
I wasn’t going to say it… i kept away from this thread for many days. I didn’t want to turn it into a thread about thread – a meta-thread.
Maybe you should talk to Loren he said “he has done a thousand of them” 
As far as the old thread (pun) versus cork argument, CORK IS CLEANER!
Jon
If attempts to rejuvenate the cork are not succesful, other than having a professional re-corking fix, I recommend using a small piece of drafting tape. Using the draftng tape, it is easy to get just the right amount on tension to seal and tighten the joint but not to stress the tenon.
Exactly. He has done a thousand of them, in a machine shop with a lathe, and using an overlapping joint instead of a butt joint. Go poke someone else.
Heh heh, easy there Glauber, I don’t think he was actually trying to hurt me with that stick. 
Loren
You will notice Glauber, that I acknowleged Loren’s expertise right from the beginning, So like, chill out…
Loren,
How much do you guys overlap the cork, when I have done it I let overlap a little, about 1mm and then sand off the bump. Yes Glauber, using a metal lathe, to sand.
Jon
You haven’t just been cutting both ends of the cork square and then wrapping with an overlap have you… This would of course leave a gap in one location between the cork and the tenon.
What we do is cut the cork an inch or so long, then taper one end (grinding by hand on a grinding wheel). This end get’s glued to the tenon first, which will eleminate the gap as you overlap. I’ll typically overlap an inch or a bit more on a flute size tenon, knowing that approximately half will get ground/sanded away. Once the cork is glued on the tenon, we set up a special grinder on one of the lathes, grind the cork concentric, move to another lathe, and sand to fit, with the usual cosmetic work to follow.
Loren