Chiff and Fipple Forums

I have a delrin flute, bought second-hand, and the cork on the joints is compressed and brittle. The joints are a little wobbly, even. I don’t really want to replace it with more cork. Is there anything wrong with thread-wrapping it? Or even just wrapping it with Teflon tape?

Thanks!

My first instinct was to say "yeah, feel free to thread wrap it". But then I had a sudden attack of doubt. Some time ago, I did a study into tenon strangulation in thread-wrapped flutes. It was motivated by being asked to fix up a couple of flutes whose tenons had really collapsed under the tension of the thread. You can find the study starting at http://www.mcgee-flutes.com/wrap-survey.htm (if you are a real glutton for punishment). One of the things we found was that the earlier timbers, boxwood and cocus, were much more prone to this crushing damage than the later, stronger timbers like ebony and blackwood.

We tend to think of Delrin as pretty well indestructible, and so it's probably quite capable of withstanding the accumulated force of hundreds of turns of thread. But we should also remember it is a plastic, and therefore flexible. We notice that when we ream the stuff - you have to push the reamer a bit further than you would with wood in order to end up with the same bore diameter - simply because the stuff prefers to swell to avoid the reamer than be cut. It may well be that it prefers to shrink rather than put up with the thread pressure.

So let me be cautious and say I think thread would be OK on Delrin, but it might depend how thick the wall under the cork trough is. This would probably be a good test: Wrap it with thread and monitor it. If you find the thread band comes loose after a while, then perhaps abandon thread. It might mean that the poly is yielding to the pressure.

Can't see any problem with Teflon (PTFE) tape other than you need to carry some of it as it tends to compress.

I've used Waxed Thread on several Bagpipe tenons with no ill effects, although what Terry says about being caution is important. I've also used Teflon Tape by itself on Tenons. Its easy to use and works fine and can be removed at any time. I think Cork is a good choice if you've got the skill set to put it on, I don't unfortunately or I would use it. Looking at all the Flutes, Whistles, Clarinets and Bagpipes I've owned I've had all 3 options on different Instruments and one option seems to work about as well as the next. My Old Pipe Instructor years ago Sir Robert Bell would have thread wrapped tenons and then would Teflon Tape the Hell out of them. on top of the thread. I never questioned Him as you never questioned your Pipe Instructor
BTW it takes 7 years to become a PIper