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How To: Know When Your Soda Bottle Chamber Is About To Blow

Post questions and info about pneumatic (compressed gas) powered cannons here. This includes discussion about valves, pipe types, compressors, alternate gas setups, and anything else relevant.
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How To: Know When Your Soda Bottle Chamber Is About To Blow

Unread postAuthor: MrCrowley » Fri Jan 16, 2009 11:47 pm

Me and some friends picked up some dry ice from a B.O.C outlet. At $5NZD a kg, we bought about 4kgs. The main purpose was for what you see in the video, but I also used it for my first burst disk cannon successfully.

End result, I am actually quite surprised at how deformed these bottles get before exploding and how much pressure they can take. I don't have any figures to give you, but the video just gives you an idea of what happens to the bottle in its final moments. Most of the video is sped up, and then slowed before the explosion. Real time was about 2 minutes.

I have another one of a Coke bottle, though the video footage is worse, the bottle develops what resembles a huge tumour at the neck of the bottle. The Sprite bottle was more uniform, but this Coke bottle had a sausage like tumour coming out of the neck.

The sound is bad because of the wind but you get the idea.
Oh and btw, this is legal in NZ because technically i'm just testing the burst pressure of a chamber with a gas and only requirement is that i'm with someone who's 18 (i'm only 17).

So how do you know when your soda bottle chamber is about to blow? it will probably look a bit like this :wink:
[youtube]http://www.youtube.com/watch?v=IEZ2uibNkHA[/youtube]
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Last edited by MrCrowley on Sat Jan 17, 2009 3:59 am, edited 1 time in total.
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Unread postAuthor: dudeman508 » Fri Jan 16, 2009 11:54 pm

i did this with my dad about a week ago but we had to stop becouse we got scared the neibors would call the cops becouse of the noise
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Unread postAuthor: MrCrowley » Fri Jan 16, 2009 11:56 pm

Yeah they are pretty loud, one person on an opposite field came up to us when we had finished and asked if we were shooting anyone and how many people we'd killed as a joke :D
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Unread postAuthor: jon_89 » Sat Jan 17, 2009 12:49 am

So any idea how much pressure dry ice can produce?
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Unread postAuthor: MrCrowley » Sat Jan 17, 2009 12:54 am

jon_89 wrote:So any idea how much pressure dry ice can produce?

Dry ice is the solid form of Carbon Dioxide. When dry ice melts it changes into CO2 gas, which you should know is at around 850PSI at room temperature.
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Unread postAuthor: jon_89 » Sat Jan 17, 2009 1:01 am

Well I have never messed with it before. Maybe a dumb question but is it possible to put to little in a bottle to were it wouldnt burst? I ask because maybe I will use this in my burst disk cannon. :twisted:
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Unread postAuthor: MrCrowley » Sat Jan 17, 2009 1:09 am

Maybe a dumb question but is it possible to put to little in a bottle to were it wouldnt burst? I ask because maybe I will use this in my burst disk cannon.

Yes, but it would be difficult to control and very unsafe. Just use a metal chamber and make some burst disks that will blow around 300PSI.

For a 3/4" union, I took an A4 size sheet of tin foil, folded it in half, then half again, then half again, then half one more time (IIRC) and I could get 2 burst disks that would blow at under 350PSI from it.

If you don't fold it in half the last time, you can get about 4 or 5 ~180PSI burst disks.

If you still don't realise, this is potentially 800-900PSI you are dealing with, think about that before asking anymore questions.
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Unread postAuthor: jon_89 » Sat Jan 17, 2009 1:27 am

Oh I realize that is pretty high pressure. I was just curious because all I got is a shock pump for 400 psi. I dont see how it could be dangerous ( other than it being cold ) if I know how many layers will burst at what pressure which is exactly like a pressure relief valve. For example I know with my 1 inch union one layer of aluminum foil bursts at 20 psi.
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Unread postAuthor: MrCrowley » Sat Jan 17, 2009 1:33 am

I dont see how it could be dangerous ( other than it being cold ) if I know how many layers will burst at what pressure which is exactly like a pressure relief valve. For example I know with my 1 inch union one layer of aluminum foil bursts at 20 psi.

You don't see how it could be dangerous using a plastic soda bottle with CO2 when i've just demonstrated to you what happens to soda bottles at an unknown PSI?

Or are you talking about using dry ice with a metal chamber? Which is safe as long as the lowest rated component is your burst disk.
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Unread postAuthor: jon_89 » Sat Jan 17, 2009 1:40 am

Metal for sure. I have been around those "dry ice bombs" before dont get me wrong they are cool but something about 800 psi, a soda bottle, and pieces of plastic flying at what ever speed doesn't quite enthuse me.
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Unread postAuthor: CS » Sat Jan 17, 2009 3:38 am

I know back at my house we used to tie weights to the neck of bottle and through the things into the pool. No shrapnel, and a lot less noise. I thought it was just as cool if not cooler. Just an idea.
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Unread postAuthor: jackssmirkingrevenge » Sat Jan 17, 2009 3:39 am

Very familair to see PET swell up like that before bursting, the bottles are hardier than they might seem but when they go, they go.
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Unread postAuthor: MrCrowley » Sat Jan 17, 2009 4:04 am

I have a 160PSI pressure gauge i'd be willing to tap into the bottle, hopefully it wont suffer too much damage.

I will try and tap it in the bottle cap, so it doesn't affect the integrity of the bottle and make the bottle fail at a lower pressure. Wonder if I can do it without epoxy...seeing as I have none (sorry JSR, but I used my emergency rations hidden in the heel of my boot when I was breaking into a top secret terrorist organization safe house and accidently broke a pot plant upon jumping the 15' barb wired wall) :oops:

:D
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Unread postAuthor: john bunsenburner » Sat Jan 17, 2009 7:10 am

Ironacally eanoth a something very similar came up in the national chemisty olimpiad, just it involved sodium instead. Oh and the bursting pressure lies at about 10bar for a PET bottle of 1.5L.
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Last edited by john bunsenburner on Sat Jan 17, 2009 3:41 pm, edited 1 time in total.
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Unread postAuthor: POLAND_SPUD » Sat Jan 17, 2009 7:57 am

@ MrCrowley very interesting vid.... any idea how many liters of Co2 can you get from 1 kg of dry ice ?

LOL you are only 17 ? I thought you were of my age or older
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