runne (Newbee)
04-14-03 03:51
No 426482
      Pressure Ratings on PETE Bottles  Bookmark   

I found the following here:

"Won't it explode from the pressure?" is another worry. Again, very unlikely. The plastic 2 litre (2 quarts aprox. to you Americans) pop bottle is made of PET, an old and strong plastic. A PET (polyethylene terephthalate) bottle can withstand 150 PSI depending on the temperature. They *can* blow at 50 PSI or less. Be aware of this! Never go near a pressurized bottle. We have never been able to get a seal at the mouth good enough to come anywhere near that pressure. The water always begins to squirt out of the bottle long before that. We did pop a vinyl hose once (LOUD!), but that was with a small air compressor. If you can devise a better seal, I think you have the brains to realize the possible danger of the bottle or air line bursting. Limit the kids to a bicycle pump if you want. Again, think about what you are doing.

Thank you for contacting The Coca-Cola Company via our Web site.

The amount of PSIs (pounds of pressure per square inch) that a package is able to withstand depends on the volume of carbonation and is based on the product rather than on the package. At lower temperatures, the pressure is lower; at higher temperatures, the pressure is higher.

A can is able to withstand over 100 PSIs.
A 6.5 ounce glass bottle can withstand 225 PSIs.
A 16 ounce bottle can withstand 175 PSIs.
A PET bottle can withstand 250 PSIs depending on the temperature.

I hope this information is helpful. If you have additional questions or comments, please visit our Web site again.

Gina M. L'Heureux
The Coca-Cola Company
Industry and Consumer Affairs


A snippet of a email from Bruce Berggren to me contained some other pressure ratings, namely:

>500ml (couldn't fail with 170psi pump)
>1 liter (failed at 170)
>2 liter (failed at 125)
>Granted, this was only ONE specimen each.

I've never run a pressure test personally so I'm asking Coke for some more info on this. Meanwhile, you might play safe at 100 PSI. The w-rocket group thinks Coke bottles are some of the weaker types of PET bottles.

Can anybody find a more scientific study of this?
04-14-03 04:03
No 426485
      more ideas...  Bookmark   


Another attempt to "explosion proof" a bottle was dipping the bottles, after completion, with fins attached, in a liquid vinyl dip solution. This was to add another layer of skin over the rocket. I also used a spray vinyl from an aerosol can. These materials as commonly used to cover the handles for tools."


I had contacted one bottle manufacture who could make an extra heavy duty bottle, just for our application. There was also discussion about including fin and wing designs in the molds for the bottles. However, presently there are not enough sales to support buying a minimum order of a semi-truck full of rocket bodies.
(Hive Bee)
04-14-03 04:26
No 426490
      Runne that is most excellent infromation.  Bookmark   

Runne that is most excellent infromation. Thank you smile

"Sometimes I sits and thinks, and sometimes I just sits." Satchel Paige
(Hive Bee)
04-14-03 04:37
No 426493
      " Newbee wings "  Bookmark   

Nice work runne intresting post, post like this will help you get your " wings "      .

Littlejase       smile      .

                          " Better to be than not to Bee "
(Hive Bee)
04-14-03 04:52
No 426499
      That means it would be even safer  Bookmark   

to use 1L pop bottle. With your recipe pupilage, would it work good or would you have to scale down?
(Hive Bee)
04-14-03 06:03
No 426513
      I would stick to the 2L bottle, the whole game  Bookmark   

I would stick to the 2L bottle, the whole game is to allow as much surface area contact for O2 transfer,but I do not see why you could not scale down by half and do a nano RXN in the 1L bottle.

"Sometimes I sits and thinks, and sometimes I just sits." Satchel Paige
(Hive Addict)
04-14-03 06:45
No 426525
      Why not use big glass champagne bottle?  Bookmark   

Why not use big glass champagne bottle?Like a 2 liter one.It think they are tested @ 10 atm or even higher.

For those about to synth,we salute you
(Hive Addict)
04-14-03 07:18
No 426534
      latest water rocket tests  Bookmark   

showed 15atm (220psi) for better quality PETīs (you feel it, thicker but still elastic, huge regional differences!) and 20atm (290psi) for choosen ones. (no signs of use or mechanical stress under polarized light.
ATTENTION! Donīt panic when at about 12atm the bottom popps out forming a halfsphere then! Thats usual and doesnīt hurt.
At 80°C about 70% of the mechanical strength is claimed (minimum) - relates more to strength against impact, the pressure holding possibilities are not influenced at all rather enhanced. (thats from how they are produced).

Champagne bottles have the advantage that drinking them empty is more fun. The rest is disadvantages - one invisible scratch and the shards stick in your face. PET bottles usually just pop open, sometimes the neck goes away. So it is advised to strengthen the neck of PET bottles with fibreglass-epoxy. So you can make some fixings for the valve also as thats the point of failure in most cases.
Better: Pressure a PET to the point the bottom pops. Then laminate with fiberglass or better aramide/carbon and high quality epoxy. Cure under vacuum/heating in a autoclave. This way ultralight gasbottles are made rated for about 400atm to 500atm (7000psi), hydrogen and else. But already the glassfiber/epoxy without autoclaving makes the bottle safe for about 50atm, more as you will ever want to apply. Just donīt forget to pop the bottom before laminating, some heating with a hairdryer makes this easier (say smoother).

nothing special