Super Soaker Central

Does anyone have any idea as to the extent of pressure cause by an elastic bladder? Specifically, I'm interested in the amount of pressure normally generated by a mid-size cylindrical elastic bladder (like that in a CPS 4100).

With air-pressure applications I can easily calculate these sorts of things, but I'm lost when it comes to elastics! I'm curious because I am currently building a CPS homemade and many of the valves are being made from scratch in order to save weight and increase customization. If I know the maximum PSI generated by a full elastic bladder, I can determined which materials I want to use in construction.

Thanks!

If you know the the chamber's unexpanded dimensions, and its dimensions when a given amount of water is pumped in, you can determine the strain. If you then know the elastic modulus of the rubber you can calculate the stress in the rubber, and from that the pressure in the water.