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Handheld, easily concealed helium cylinder? Answered

Hi! I'm looking for advice on where to find or how to build a handheld helium delivery device. I just need to blow up 1 balloon at a time for a magic trick. The device needs to be small enough to hide in my hand/be ditched in my pocket after I've blown up the balloon.

Any advice greatly appreciated! Thank you!

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Jack A Lopez

11 days ago

Also regarding handheld hydrogen, did I mention metal hydrides? A metal hydride plus small electric heater, to drive the hydrogen out?

I don't think I have ever seen any metal-hydride based hydrogen storage devices, in real life, because it is a kind of still being developed, not yet commonplace, technology. I think there are places that sell metal-hydride based storage, for hydrogen fuel cells, but I think these are still kind of pricey.

https://en.wikipedia.org/wiki/Hydrogen_storage#Met...

Nickel metal hydride batteries,
https://en.wikipedia.org/wiki/Nickel%E2%80%93metal...

have some kind of metal-hydride in them, and they are cheap and easy to find, but I am not sure how hot you would have to heat that metal to boil the hydrogen out of it, or how much hydrogen is present, e.g. in the metal-hydride found in a single AA sized NiMH cell.

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Jack A Lopez

11 days ago

Does it have to be helium?

There are dozens of non-toxic gases that can inflate a balloon, including air, which is so cheap most people breathe it, for free.

Does it have to be a lifting gas?

https://en.wikipedia.org/wiki/Lifting_gas

I mean does the resulting, inflated balloon, have to be buoyant; i.e. floats up instead of down?

To me, hydrogen (H2) seems like a good choice, possibly. Also I think the flammability of hydrogen is overrated. You can find videos on Youtube of people intentionally igniting balloons filled with H2, and also stoichiometric mixtures of H2 and O2, which is explosive rather than merely flammable, which is why you would want to go with mostly H2.

Also there are methods for making H2, via chemical reaction, so that might be the method for a handheld device. Instead of storing pressurized gas, it would store solid and liquid reactants, e.g. magnesium metal and dilute hydrochloric acid, which when combined, would make hydrogen and water vapor, for to fill your balloons.

Although, I have to admit there may be some significant technical challenges to overcome, to make a contrivance like this safe enough to use. The main problems that come to mind, are that this device would tend to get hot from the heat produced by the reaction, and also there would probably be a tendency for it to leak, or spray, acid everywhere.

Which makes me think: if instead of dangerous heat, dangerous cold would be preferable, consider using liquid helium.
https://en.wikipedia.org/wiki/Liquid_helium

It can be stored at ordinary atmospheric pressure, but only if it is constantly boiling, i.e small amounts of liquid lost to boiling, as heat slowly creeps into its thickly insulated container.

https://en.wikipedia.org/wiki/Cryogenic_storage_de...

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Downunder35m

12 days ago

Your problem is not the cylinder but the rating for it.
Pressure containers need to be certified as otherwise they count as a dangerous weapon/device now in most countries.
And since Helium comes at about 17-20kPa it can be very hard to find suitable regulators and transfer systems.
If neither safety, now regulations are of your concern you could consider a tyre inflation device.
They use CO2 capsules, same type and size as for your whipped cream.
Should not be too hard to create a suitable adapter to go between a helium bottle and the inflator.
But better test it properly in some "bomb proof" enclosure as you don't want to find out that it fails while you hold it your hand...