I was drinking some pop during lunch from a 2 liter bottle and thought I'd pass on a little tidbit of information. Years ago I bought a CO2 bottle and regulator so I could carbonate things. I was worried about one of the kids using the regulator at too high of a pressure (it goes up to 60 psi = 0.4 MPa) and blowing up a bottle, making a mess and perhaps injuring themselves.

Thus, I set up a pressure test of a few 2 liter pop bottles. I machined an aluminum cap to fit the bottle (cutting a regular 60 degree vee thread works fine) and used a standard US hose washer as a seal. I'll post a dimensioned sketch, photos, and instructions if anyone's interested.

Anyway, I hooked the bottle up to my air compressor and put the bottle behind a wall and cranked up the regulator. Much to my surprise, I was not able to rupture any of the bottles I tested. My regulator goes up to 120 psi = 0.8 MPa. These pop bottles are surprisingly tough.

My worry about the kids was groundless. The only one home is a 20 year-old daughter and she always just says, "Daddy, this pop is flat -- would you fix it?" I assume she inherited my laziness...

 

Now I know how kids blow up mailboxes with 2 liter bottles charged with Drano and aluminum foil. That is a lot of pressure.

 

My dad built a blow-down type wind tunnel using 1 liter pop bottles as pressure vessels. They usually blow out at around 450 psi.

By the way...you don't want to be standing next to this one when it happens. It sounds like about a pound of C4.