I'm an artist currently using propane and butane in my show where I put the gas into a soap bubble and light it to produce a nice flame.

But I'd like to start working with a lighter than air flammable gas, that's relatively easy to get hold of, and as safe as it possibly can be.

The propane/butane I use comes in small canisters and the biggest risk, as I see it, is forgetting to close the tap.

Any ideas?