zlacker

>>jnord+(OP)
Isn't H2 better because better lift and being a molecule of two hydrogen atoms it is not quite as slippery as helium and quite easy to make?

From wikipedia "lifting gas"

"Helium is the second lightest gas (0.1786 g/L, 14% the density of air, at STP). For that reason, it is an attractive gas for lifting as well.

A major advantage is that this gas is noncombustible. But the use of helium has some disadvantages, too:

    The diffusion issue shared with hydrogen (though, as helium's molecular radius, 138 pm, is smaller, it diffuses through more materials than hydrogen[4])."

>>airbre+m9c
and at this scale it seems like the hazards of h2 would be pretty minor. You're not exactly going to have a Hindenburg situation with only a couple dozen liters of H2.