Page 1 of 1

LED Strip for testing leaky pads?

Posted: Wed May 08, 2019 8:45 am
by Conical bore
Are devices like this useful for testing pad seal on a keyed "Irish" wooden flute, or a waste of money?

https://musicmedic.com/products/repair- ... light.html

https://musicmedic.com/products/repair- ... light.html

My keyed flute passes the suck test, but since that pulls the pads into tighter contact, I'm still suspicious that one or more key pads may still be just a hair leaky when resting on the hole. It's one of those situations where I'm getting a pretty decent low D, but wondering if it could be just a wee bit better, and not sure if it's the pads or me (probably me). And I'd like to be sure.

Re: LED Strip for testing leaky pads?

Posted: Wed May 08, 2019 9:35 pm
by an seanduine
I'll pass on a small piece of 'folk wisdom' I got from David Levine (Cocusflute). He was having a small problem with the botton 'D' on a keyed Olwell. The 'C' key was the culprit. . . slightest difficulty in it's seating. Take a rubber band and use it to force the 'C' key closed. Presto, Pat's signature bell note came booming out. I tracked the same problem down on one of my own keyed flutes (not an Olwell).
You can isolate each key separately with a little extra rubber 'muscle'. If anything jumps out, a little heat and moisture over time can help seat the pads. Good luck.

Bob

Re: LED Strip for testing leaky pads?

Posted: Thu May 09, 2019 12:34 am
by paddler
Another thing you can try is to take the keys off and use blu-tack or some other similar reusable putty, to seal all of the keyed (closed) holes.
Be careful not to push it too far into the hole -- you don't want it protruding into the bore. And don't seal off the open keyed holes on the foot
at this stage.

Once you have done this play the flute and see if it is noticeably more resonant. I often find that older keyed flutes play dramatically better
when I do this. Knowing this gives me incentive to diligently work through the keys, one by one, to find out if the flute plays better or worse
when I add that key back instead of the blu-tack.

I find that it is quite common for a flute to pass the suck test, but still have a leak. As you pointed out, suction helps to close a leaky pad, whereas
playing the flute generally introduces some internal pressure oscillations that will push a borderline leaky pad open, especially at the locations in the
bore that correspond to pressure antinodes for the note being played. These are the points in the bore that experience large pressure changes. On
many D flutes the c key is fairly close to the location of the pressure antinode for the bottom D, so it is often a culprit if that note is weak, as Bob
pointed out). The harder you push the flute the higher the maximum pressure at these points and the more likely you are to cause a weak key to
leak and weaken the note being played.

Leaking is often due to either a deteriorated pad which needs replacing (ideally with a high quality, thin, leather clarinet pad), a poorly seated pad,
which needs re-seating (ideally by floating it back into place using heat), a bent key, which needs straightening, or a weak spring, which needs
repositioning/bending or replacing. Of course, there are other reasons for leaks, such as cracks or damage to the tone hole rim on which the pad
sits, but the former are the most common key-related reasons for leaks in my experience.

It is definitely worth spending time to trouble shoot these issues. It can greatly improve the performance of a flute.

Oh, and to the specific question asked, I don't think an LED strip would really help. The standard, non-technological approaches will allow you to
track down the problem 99% of the time ... if you spend enough time and are careful about it.

Re: LED Strip for testing leaky pads?

Posted: Thu May 09, 2019 7:30 pm
by Conical bore
Thanks for the feedback! Okay, I'll skip the light test and work on isolating individual pads. The flute is probably fine. I may just be down that rabbit hole of trying to make sure nothing is leaking, but this will help me verify.

Gee... I never had this issue, or paranoia with a non-keyed flute! :) Then again, now that I've hopped on the keyed flute train, I wouldn't want to go back. Just part of the learning process, and thanks for the help.