Chiff and Fipple Forums

Hi folks.

I have a slight problem. I bought a used delrin 6 keyed flute about 4 months ago as I wanted to start utilising keys. I also wanted to try a flute in delrin but that was a side issue.

It's a decent flute and the keys are fine, but the cork is a bit worn out. What I mean by this is that over it's c.10 year life the flute has likely been kept assembled for long periods and the cork no longer keeps the flute tightly together. When assembled, the flute 'sags' a bit.

As no one wants a flaccid flute, I need to get it re-corked. However times being as they are, it may be easier to cover the cork with thread, or replace the cork with thread altogether in order to achieve a more tight bond. From those with a bit of experience:

> Is it ok to just cover the cork over with thread?
> Is it better to remove the cork altogether and start over with thread instead?
> Any pitfalls or dangers in removing the cork, or tips as to how to acheive it?
> Is there a particular type fo thread that's best, or will any aul' thread work?
> If I transition to thread, do I use cork grease on it or some sort fo wax?

Any advice much appreciated. Thankfully working with delrin rather than wood which would make me more nervous.

In the case of a delrin flute: threading over cork you plan to replace sooner or later should be fine as a temporary fix. The thread will compress grooves into the cork though so don't be surprised. If the cork is bad anyway that should not matter.

Supposely it is not hard to replace cork on a flute. Googling "replace cork on clarinet" will get you lots of tutorials.

I had an ebonite M&E for awhile and the previous owner had put teflon tape over the cork. I bought some cork thinking of doing it but never got around to the job. The cork was inexpensive on Ebay. It wasn't my every day flute so I never got around to fixing it before I sold it to a friend. But the plumber's telfon tape kept it going for less than 99 cents.

(Semi permanent plumber's tape would not be recommended for a wooden flute).

Thanks Buster, I'll give the string a try. Once the restrictions end I'll get it recorked properly.

I did think about trying some plumbers tape as a temporary solution. I might try that first and see how well it works. Just feels a bit odd but needs must.

Hi,

You might find this video helpful.

Cheers,
Julien

It is not hard to replace the cork. I was surprised how well I did and it was my first time although it took two tries so get extra cork if you are doing this yourself.

Be very careful if you use plumbers (teflon) tape on a wood flute, for future reference. Is very easy to get the tenon much tighter than you intend and because the tape is so slick it may result in a cracked tenon. It is a quick fix but one I would only employ on a delrin flute and never on a wooden flute.

Threaded tenons generally have combing (grooves) to accept (& help lock in) the thread. If the tenon is smooth and originally designed for cork, I think one should continue to use cork.

kkrell wrote:Threaded tenons generally have combing (grooves) to accept (& help lock in) the thread. If the tenon is smooth and originally designed for cork, I think one should continue to use cork.

These grooves are also standard on many originally intended corked tenons, and help to solidify the bond of cork as well...

One thing that hasn't been mentioned -- one should use nylon thread or dental floss. No cotton thread as it will swell when wet and make the tenon too tight.

Thanks everyone, this has been really helpful. Much appreciated.

Sedi wrote:One thing that hasn't been mentioned -- one should use nylon thread or dental floss. No cotton thread as it will swell when wet and make the tenon too tight.

And yet flutemakers use (embroidery) cotton thread. Go figure!

I think that tip came from one of the makers here on the forum.
But there are opponents to thread-wrappng a tenon:
http://www.mcgee-flutes.com/wrap-survey.htm

I think the arguments for and against thread, which I do find very interesting, probably have less relevance for Delrin flutes. If the floppy flute in question was wood I'd definitely go with cork again but as it isn't, I've ordered some embroidery cotton as per that very helpful video and go with that. Seems a simple and eminently suitable solution for a delrin flute.

For those of you that do cork, how do you cut the bevel? From what I've read, it seems that a really extreme bevel is desirable.

To cut the bevel I used one of those razor blades that have a metal back on them. They don't flex and they are wider than the cork. I did the cut in one motion and the back kept the cut straight.

The bevel? Is that where one end is bevelled so the other end can pass over it, and then get trimmed off?

I don't do a bevel. I cut a strip of cork to fit the width of the trench in which the cork will be glued. The strip of cork is just a bit too long; its ends would overlap if left untrimmed. I put the piece of cork in place and mark with a pencil or a little cut with the scalpel where the ends would overlap. I cut across that pencil line or even a smidge shorter. (I like the No 12 scalpel and a metal edge to cut against.) When I offer the strip back up to the tenon again, it is inevitably a tad too long. (The "tad" is a closely defined unit of length in the British Imperial system, lying somewhere between a "bit" and a "gnat's whisker". The previously mentioned "smidge" lies between the "bit" and the "tad". Don't worry, you'll get the hang of it.) I estimate how much too long, then cut that off. I'm usually right, but very occasionally, I'll remove the gnat's whisker remaining. Then I glue the cork on using contact cement.

Remember to massage some cork grease in before reassembling.....