Public Lab Research note


170cm hydrogen-filled weather balloon burn test

by mathew | May 21, 2012 04:12 21 May 04:12 | #2152 | #2152

From Launch PSU, at Portland State.


2 Comments

also a great video showing aluminum/lye generation in a nice slow controlled manner: https://www.youtube.com/watch?v=Rl8Iby4AuWc

There seem to be lots of videos of that sort of generation. It seems like it'd take a while or a larger reaction container to fill a 5' balloon without taking forever.

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I've tried the aluminum/lye method too, and yes, it's nice and controllable but slow. You can make it fast (very fast even), but then the temperatures get higher and then the vapor from the water gets into your balloon. Maybe a really long tube would allow it to cool..

What I've been thinking of (no idea how viable this is, since I'm so bad with chemistry) is would it be possible to produce hydrogen inside a big closed, airtight bottle, in advance of the flight. The pressure would build up and then once in the field you could fill a balloon with the hydrogen from the bottle quite quickly.

Doubts: would pressure keep building up, or would the reaction stop under pressure? Would the hydrogen in the bottle slowly mix with the acid and become lye+aluminium again?

Also a 5' balloon would require $30+ worth of lye where I live, so you might almost buy helium :)

The video is really cool but I'd be wary of doing it close to grass/trees.

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