Synthetic cork v. natural cork

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Terry McGee
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Re: Synthetic cork v. natural cork

Post by Terry McGee »

GreenWood:
Delrin...sacrilege !

Heh heh, confronting, eh?

One of the interesting benefits of working a lot with period flutes is that you get to see what doesn't work well, and old-time stoppers were a good example. They were typically wooden rods with a tapered screw thread cut at one end for screwing into the cork, and a parallel screw thread at the other for engaging in the threaded hole in the end cap. Wood is just not a good material for cutting screw threads in, and you get to see (and have to fix) a lot of failures. And the screw threads have to be coarse, which makes fine setting of the stopper tricky.

The Boehm flute replaces that with a fine threaded rod in metal, typically 4mm (even in US-made flutes?). Typically silver-soldered to a silver disc to act as the front of the stopper, getting around the second issue, which is that the face of a plain cork stopper is easily damaged. I stole that approach for a while, but still didn't like it. The cork seemed to want to shrink over time. And good quality cork was becoming an issue since wine bottles were increasingly going screw-cap.

Hence the current version, in delrin with a thin cork seal set around it. Easy to control the tightness. Smooth, totally waterproof front face. Easy to replace the tenon cork strip if ever needed. And a fine, strong threaded metal rod to mate with a threaded insert in the cap to allow easy adjustment.

Romantic? Not particularly. But the stopper's lot in life is not a romantic one - it serves a really important but invisible role. So I reckon this is a place where utility trumps romance!
GreenWood
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Re: Synthetic cork v. natural cork

Post by GreenWood »

"Heh heh, confronting, eh?"

Sort of, but it was tongue in cheek. The difference is not really about romantic ideals, but just personal approach to the instrument. I'm happy poking the cork into place, or adjusting it, with a cleaning rod, and usually it does not get further adjusted from a position I am happy with except when cleaning the whole flute...and gets returned to same. I am not sure if micro adjustment should be by cork placement or player embouchure, and decided that continuously playing with cork position to try to improve sound was probably a distraction.

Others might differ, and so would want to be able to adjust with threaded cap, and there I agree with you... were I to make such a contraption it would want to anchor firmly on the stopper, and I would probably choose Boehm's way for ease of construction and using basic materials, if not actually just gluing the rod three quarters way into the cork somehow.

For cork shinkage I don't know, but as I don't mind preparing stoppers the thought doesn't put me off. The oldest cork I have in place is three years or so and it still fits fine. Even changing once a year would be no bother, but I imagine most people would find that a hassle. I find it fun collecting and shaping cork bark, even if most would not miss an excuse of buying a quality bottle of wine. Come to think of it, some are over a century old with cork still intact, so maybe shrinkage is humidity... or very small beetles that also have a form of wine aversion ?

Anyway, I'll just say I find your approach with delrin functionally elegant, and similar for delrin flutes and so on.

[As for damage to the cork from cleaning etc., I suppose it depends how anyone goes about that. I will swab the flute after playing with a cloth wrapped also around end of rod and being careful to not push on cork much, and that doesn't seem to damage it. Older texts advise removing the cork and cleaning after each playing, and there I could imagine eventually it would get damaged, but that would depend on if the player expected a perfectly smooth and level face to it ?

I take out the cork a few times a year and that doesn't seem to cause damage, and probably oil added or pushed up the bore when being cleaned levels the cork and also possibly forms a sort of concave at that end which otherwise anyone would pay handsomely for in the form of a speciality dished stopper that improves the sound at the speed of light ]
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