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How do you make a pressurized 2 litre coke bottle instrument Answered

I have found this video on youtube of this guy who made an instrument out of 2 litre soda bottles. He says he drilled a hole in the cap and put a tire valve through the hole. Then he used silicone to seal the hole, screwed in onto the bottle, and pressurized it. Then he hit it on his hand and other various objects and it produced a very clear sound.

I have tries to recreate this, pumping my bottle up to 120 PSI with no results. I noticed that he is from the UK and that his bottles were shaped differently than mine(from America), being more of an hourglass shape. Would this have any affect? Also i noticed that when i was doing it that there was a lower PSI(somewhere less than 100... mabye 80ish?) where i could hear a faint sound similar to in the video. Is it possible that I missed the correct PSI?

4 Replies

RavingMadStudios (author)2010-05-17

You can skip the whole cap-drilling/silicone-sealing/schrader-valving part, and just pressurize the bottles with dry ice and a bit of water.*  It's a whole lot easier, and works much better too.**

*do not, under any circumstances, pressurize the bottles with dry ice and water. that would be stupid.

** this is a flat-out lie.

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Kiteman (author)2010-05-17

Those are not (UK) standard 2 litre bottles.

2l bottles have parallel sides.  They look more like the 1.5 litre "share size" bottles.

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lemonie (author)2010-05-17

He's got them pumped-up pretty tight there. Like steve, I'm a bit concerned about a catastrophic failure.
The 2L classic-Coke design PET bottles probably have heavier walls, see what you can get out of small classic-shape PET bottles first?
(These make a big bang if they burst)


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steveastrouk (author)2010-05-17

I like the Fujara.

I suspect the shape of our bottle would affect the stiffness of the sides, so stops them resonating pleasingly.

Pressurising coke bottles to 8 Bar and then banging 'em doesn't sound like a good plan to me !

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