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Background

I have been learning to play the bagpipes on a practise chanter for some time now. This is basiaclly just the chanter on which you play the melody without the bag and the drones. Since I have to wait some months to get my real bagpipes I tried to build one myself using freezer bags and ducktape. This is the result:

the bag

So instead of blowing the chanter directly with the mouth, the air is saved in the bag. To play a tune I use my left arm to apply pressure on the bag to force the air through the chanter which then produces a sound.

The problem

To stop the air from going out to where it came in, a bag gets blown through a non-return valve. So the air can only exit the bag through the chanter. My first attempt of crafting such a valve looked like this:

my non-return valve

This is just a straw with some ducktape. It kinda works but there is still a bit of air going back out. Also it doesn't last long since the moisture in my breath removes the stickyness of the ducktape. Which brings me to my question: How can I craft such a non-return valve? It has to meet the following requirement:

  • Resistant against moisture from my breath.
  • Doesn't let any air go out of the bag.
  • Has to have diameter around 0.5 mm. If it's too thin it gets too hard to blow.
  • Withstands a reasonable pressure from the air trying to get out.
  • Doesn't use too unusual material. I should be able to get it in a supermarket.

Hoping for some interesting ideas!

  • Can I have an explanation for the downvote? I am rather new to this site, so I would appreciate suggestions on how to improve this question. – Denker May 12 '16 at 14:33
  • Not really crafting, but you could try cutting out the valve assembly from a bicycle inner tube – Dave May 13 '16 at 11:10
  • @Dave Not sure if this would work. I think those valves are constructed to let the air flow in both directions. It would be tricky to somehow open one direction permanently. Also the diameter could be too small for my purpose. – Denker May 13 '16 at 11:21
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Using the same straw & a rubber-band, cut the end off a long 'sausage-shape' regular kid's party balloon [cheap rubber one, not the expensive 'tin cushion' mylar variety] & fasten the mouth-piece inflator section to the straw using the rubber band. The other end, where you cut the end off just flaps in the breeze.

You may need to experiment with the right length to stop it sounding like a whoopee cushion when you blow, but any air pressure inside your bag will immediately seal it up as soon as the pressure inside is greater than outside.
As mentioned in comments, if the pipe is too large, the balloon is likely to turn inside-out & fail, requiring a mesh to prevent that; but I think you ought to be OK using a straw.

A round balloon might work just as well.

Actually... mylar would probably work too, but they're expensive, by comparison.

  • I've tried this and it works (sort of) as a way to improvise a one-way air check valve. The problem with using a balloon is the material is too thin to avoid being sucked inside-out if the straw/airway is of any reasonable diameter. The solution is to add a barrier (a mesh cloth?) over the hole before you add the balloon so the balloon has nowhere to go when the airflow reverses. – Robert Cartaino May 12 '16 at 16:54
  • Makes sense, yup. I was only considering a straw, rather than a thicker pipe, so didn't factor in that possibility. – Tetsujin May 12 '16 at 16:59
  • This sounds pretty neat. Gonna try it out and accept this if it works. Thanks for the great idea! – Denker May 12 '16 at 20:55
  • Use a normally flat balloon. fasten the neck of the balloon near the end of the tube. Cut the balloon about an inch long and put two strips of plastic tape on either side to stiffen up the valve. Put the end into the body of the air chamber beside your body. Now, pucker-up and practice. – Stan May 14 '16 at 20:22
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Ball checks are the classic tool for this job. You need a ball (in this case, ideally a light, fairly soft one), a cage to hold the ball near the tube outlet, and probably a very soft spring to push the ball into the tube outlet. The softer the spring, the less pressure you'll need to push the ball off the seat and blow air into the bag; the softer the ball the less pressure will need to be in the bag to keep the ball sealed (the spring helps here).

  • A ping-pong ball in a funnel taped to the end of the mouthpiece will work if you put some mesh across the funnel to prevent the "plug" from wandering out of the funnel "valve." – Stan May 14 '16 at 20:24
  • If the funnel's inner surface is perfectly round, this will probably work pretty well. If not, it'll leak air past the ball. A softer ball can "squish" a little to seal against the cone of the funnel -- and with a soft ball, you'll get a seal with just a tube cut off square. – Zeiss Ikon May 14 '16 at 21:02

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