SpudFiles

Can someone give me the pressure rating of a plastic coke bottle, sorry im a bit of a noob.

its not rated. its made to hold soda and not much else.

some people say they are good to about 120 psi. im sure it will hold it, but i really dont tust it and i personally dont think it is smart.

the way i see it is that plumming parts are cheap and a foot of pvc costs the same for a bottle of coke.

Soda bottles don't have a pressure rating, but I have tested some to 100psi, so it should be pretty safe for 60-80psi. Just remember to ALWAYS use bottles that held a fizzy drink (water bottles are bad). Also, the coca cola branded bottles tend to be thicker than the other ones I've seen. It's a good idea to test any bottle before you use it. Just fill it to the brim with water and pressurise, that way, if it bursts, the amount of stored energy will be small. And welcome to Spudfiles!

I am only filling it too 35 psi, it is alot lighter than pvc and is for a bbmg, so I should be ok, and thanks.

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Thanks man, so I will be fine.

I have taken a 2ltr coke bottle to 140psi but I wouldn't go any higher than that and wouldn't do it often.

mythbusters exploded one at 150 so you are very safe at 35

sandman wrote:mythbusters exploded one at 150 so you are very safe at 35

mythbusters is a cool show, but dont use them as a source of info for spudguns. remember the giant ball valve cannon? inconsistant opening times and a horrible cb ratio made it a horrible cannon for testing.

back on topic: yeah its safe up to about 50 psi.

ive taken one up to 145 thats about all that i would trust it to but they are fine i made many cannons with them it and they were fine

I got bored one day and took a evian water bottle to over 120psi, very loud bang

Plastic soda bottles for carbonated beverages most definitely are pressure rated. Get off you behind and do some googling.

I wouldn't say that drinks bottles are "pressure rated" - I'd say pressure tested.

Being technical, a rating is when a manufacturer has certified the product for use at a pressure. Coke don't naturally certify their bottles (that's asking for trouble), but can be coerced into giving information about what they've been tested to.

I'd personally be confident with a tough, non-collapsable (the evian bottles are specifically designed to be crushed to recycle) bottle at up to 100-120 psi.

They share the quality of ABS that should they fail, they tend to tear rather than shatter, which means that should anything go wrong, you'll just be short of hearing for a short while - unless you're holding your head to it.

joannaardway wrote:Being technical, a rating is when a manufacturer has certified the product for use at a pressure. Coke don't naturally certify their bottles (that's asking for trouble), but can be coerced into giving information about what they've been tested to.

Having worked in the quality control lab of a well known beverage manufacturer, I can vouch for the pressure testing of PET bottles used for non-carbonated beverages (Iced Tea etc.) - naturally not all blown bottles are tested, a sample from each mould is taken at regular intervals and the bottle is tested to failure in a sealed pressure-tester.

Typical failure figures are just over 300 psi for 0.5 litre bottles and just under 200 psi for 1.5 litre bottles. Bottles designed for non-carbonated beverages such as bottled water fail at much lower pressures, typically below 100 psi. As a general rule, the smaller the bottle, the higher the pressure it can take.

Note also that quality varies from bottle to bottle - look at the little teat at the base of the bottle, if it appears too thick then it's a likely point of failure.

I knew there was somebody on the board that new about pressure testing of plastic bottles.

There is really very little difference between pressure testing and pressure rating unless you're being picky.

"Pressure testing" is the act of collecting data. "Pressure rating" is what you get after the testing data has been examined by statisticians and lawyers. "If 99.9% of the bottle don't fail under conditions X, the cost of a failure is $Y, we sell 4 zillion bottles a year, therefore our liability will be ..."

I'm sure that the Coca Cola™ company tells their bottle manufacturer that the nominal pressure at normal temperature is such and such. But, the bottle must not fail at the pressure it'll have at 150 F, or something like that. The inside of a car will easily hit 150 F on a hot sunny day. I'm also sure there is a many page document that specifies in gory detail the failure statistics at various pressures and temperatures.

Naturally, bottlers are not interested in telling anybody what the actual testing data is or what the derived ratings are. Why should they? It would just be ammo for liability lawyers.