the coke bottle, and as far as Im aware, the pepsi bottle, are rated at 300psi. do not ask me how, or why I know this, I just do. Something to do with model sircraft but Ive no idea how the subject came about.

attaching fitting is easy, drill 2 holes in the lid, and screw in pnematic fixings. Use resin to add extra security if you want.

this is a very reliable and lightweight solution, which rex garrod used in his 12kg rexs robot challenge. (although at 50psi)

the best thing about this is, you make the lid with the fittings, and you can attach about 15 different size and style bottles to it, giving you lots of options.

1 problem, you have to drink the coke first, which apparently is bad for you?