Instructables

how much psi does a coke bottle(2l) hold?

i need to know for a a canon

wupme5 years ago
The once i have tested for an experiment could hold 60-70 easy. Over 80 some started to failure, i think most exploded over 100-110. But then again, it was hard to watch the pressure gauge on those who exploded, because i've always: "Look bottle, look gauge, look, bottle, look gauge, look that nobody stupid walks up, look gaue...." So 60 is safe if the bottle hasn't any fabrication failures, dents or was exposed to hot sunlight/heat and stuff like that.
wupme wupme5 years ago
Oh, and one thing i have to say. The explosion of such a bottle can be really strong. It nothing that would blow your windows out, but if you're not shure that it won't explode, stay at a distance of at least 15 feet. Eye and ear protection is necessary, because they really make a load boom.
After testing this with several different bottles, we found that the usual burst pressure was between 120 and 180 psi for a bottle filled with about a half liter of LN2. This may be different than a bottle at room temperature as the PETE likely becomes somewhat more brittle at the low temperature (-320 f).
JAYBLES2 years ago
I wonder if this could be used to re-carbonate a 2 or 3 liter bottle of soda that has gone flat because someone left the cap a little loose?
taz20205 years ago
i will test it right now then ill post the results.
lunakid taz20202 years ago
Still testing? ;)
rowerwet5 years ago
don't know the pressure but it is impressive to put muratic acid (concrete etching, and tin foil in a 2 liter bottle and watch it stretch until it is larger than a 3 liter before it explodes. WARNING !!! muratic acid is a caustic acid and will burn you! read the instructions for handling on the bottle!
I'd say 80 psi and dont put it up to that more than 5 times
peede15 years ago
use pepsi product bottles...they hold more psi then coke. dont ask me how i know but trust me....i know
ewilhelm5 years ago
If you take the average of all the answers so far, and drop it by 20%, you'll probably have a reasonable value. If you decide to test it out, be sure to fill the bottle with water before you pressurize it. For all practical purposes, water is incompressible, which means that when it is pressurized, it doesn't hold much energy compared to a compressible fluid, such as air. So, if you fill up a bottle with air and pressurize it, it has much more potential energy than a bottle at the same pressure filled with water (or mostly water and a little air from, say, your bike pump).
lewis685 years ago
2l bottles puncture at just less than 150psi according to mythbusters but should really only be exposed to no more than 100 if u want to keep your spleen
They'll go to about 100PSI in general, a safe working limit is around 85PSI, wrapping them in duct tape will make them capable of holding more pressure but not reliably , however it's a good way to make them safer. I've fixed your keyworks, in future it goes like so: "Cannon, PSI, bottle, coke, air, airsoft" You don't need the quote marks, just go comma space between words.
If you are using them seriously as pressure containers be warned that you are best not making any new holes in the structure to add new inlets or outlets, making cap that fits on well is better off.
Also ear protection is a good idea as said below and if youve got a bunch of them, test them all to 20% above your normal working pressure for the cannon before adding them to it permanently, that way you'll have a set of safe ones as they can have variations from manufacture.
bylerfamily5 years ago
I'm pretty sure they can take about 210.Because when I make the works bombs the take a while to explode.
Drafski5 years ago
It can hold about 80 psi. 100+ and you won't have a bottle left, just some plastic. lol haha
I agree with Dorkfish92. About 60 to 70 PSI is correct. Above 80 psi "can" result in explosion (very loud, like a shotgun and potentially dangerous) as I have seen it destroy an expensive RC airplane (it was used as air tank in the fuselage for retract landing gear). Heat and exposure to the sun will weaken it and reduce it's capacity as well.
Sandisk1duo5 years ago
don't got past 100psi i am SURE that it can take 80psi no problem
omnibot5 years ago
I don't know about psi but I had one up to 13 bar years ago and then it blew up in my hands, couldn't move my thumbs for two weeks. Important safety-tip : Don't hold a highly pressurized PET-bottle.
FYI: 13 bar=189 psi

I've read that 2 liter bottles are designed to hold up to 120 psi in an emergency, but typically don't hold much more than half that. It may become more fragile after being exposed to sunlight and repeatedly inflated and deflated.

Be sure to wear thick gloves and safety glasses.
baudeagle5 years ago
If the bottle is scratched/kinked or damaged this will hold significantly less pressure than a perfect bottle.
Firebert0105 years ago
Pressure isn't like water, containers do not have a set amount (or volume) of pressure that they can "hold". We can't just tell you an exact number, as it does not exist. What we can tell you, however is how much you should pressurize this container before it becomes unsafe or ruptures. That being said, I don't think you should make whatever it is that you're contemplating making. Chances are that it's pretty dangerous, and it's better to be safe than to be without a few fingers.
I had one a 85 psi and it held air good
About 140psi until it pops for a 20oz.
Dorkfish925 years ago
"safely", probably around 60-70psi. You can probably do more, but then it may explode.