When observing the fetish of inflation, as much as it interest me..i just wish to share some information to take in consideration when making inflation art.
Helium has a lifting capacity of about 53 lbs for 1000 cubic feet and a gaz weight of approximativly 10 lbs at 1000 cubic feet.
Hydrogen has about 75 lbs lifting force for the same 1000 cubic feet and about 5 lbs of gaz weight.
Hydrogen when mixed with lower then 17,5% oxygen concentration will NOT ignite!
Hydrogen increase potentcy with higher heat temperature, as for helium it is the opposite.
When calculating lifting potency everything have to be calculated with Volume, not size.
A 6" balloon doubling in volume is not 12".
12" is 10 times the volume of 6",etc...
When imagining a women lifting up by inflation, figuring proper size is important, unless comming up with an idea of how her body mass can be drasticly reduced before or during inflation.
As for exemple for butt or breast inflation / levitation, without mass reduction..it would rip the flesh out for it is like pulling your full weight from the most fragile body part.
As an exemple: to lift a 130 lbs women with 2 helium inflated ballons would require 2 balloon of approximate 4,3 meters each in diameter.
The formule for converting diameter of a perfect sphere into volume value is as fallow. With an exemple value diameter of 5.
2,5^(3)×3,1416×(4÷3)
Know that the value of radius / diameter will match the cubic value you are trying to fallow.
I suggest you first calculate how much weight you want to lift and then convert the cubic feet to either cubic inch or cubic cm or wherever you prefer.
Or you can keep it in feet and convert your final radius / diameter value to the value you are looking for.
When calculating for multiple balloons, like for exemple 100 ballons. First divide by 100 the final volume value required for lifting capacity and then find your individual ballon size from that value.
Also factor in weight of material, which a case for case issue.
Enjoy.