How to produce 14,000 cubic feet of hydrogen?

Okay, here is the deal. Me and a friend where thinking about filling two weather balloons( http://www.ebay.com/itm/GIANT-Weather-Balloon-Meteorological-Military-8-Dia-/330626487344?pt=LH_DefaultDomain_0&hash=item4cfadfd430) with a lifting gas, sending it up with a camera and gps-cellphone. Now, we have everything else figured out but how to get hydrogen, as it is the lightest gas. Is there any way to produce those quantities of hydrogen within a 6-36 hours? I figure I'd ask here because there are quite a few hydrogen powered vehicles here.

sort by: active | newest | oldest
According to the site you cite, the balloon will go really high and has a free lifting capacity of 1kg/2 pounds when filled

From the website
I bought the big army surplus weather balloon. I performed a HAB-Experiment flight with over the swiss alps this January the 16th. I had the skirt of the balloon removed and I had about 2.5Kg of free lift. That was a bit to much, because I filled 4.9 m2 of Helium. Anyway the balloon reached 21'500m (something around 65'000 feet) and bring me back great videos and images. No desert and great planes here: I had to climb the alps to get the capsule back!   Marco Glattfelder, Switzerland

So you DON'T need 14000 cu ft, you only need 173 !
And its a HUGE mobile phone that weighs 2 pounds.

So forget Hydrogen.


bretta (author)  steveastrouk5 years ago
Thank you, I must have screwed up somewhere when calculating the volume. Probably saved my life.
Kiteman5 years ago
The quickest and safest thing to do is buy yourself some helium, which is what weather balloons are designed to use.

Not only is hydrogen explosive, it penetrates the material of the balloon more easily than helium, so it could easily deflate much more quickly than you want or need.

That's somewhat true, hydrogen permeates a substance better than helium, when it is only a single hydrogen. But when you have hydrogen gas you have two hydrogen atoms, making it bigger than helium, and therfor leaks less. So hydrogen actually leaks less thean helium.

Two hydrogen atoms still have half the mass of a single helium atom, so molecules of hydrogen move about 40% faster than helium atoms under the same conditions.

daweim0 Kiteman3 years ago

While I see where you are coming from, this is not correct. While Hydrogen may be significantly lighter than Helium, Hydrogen has a slightly larger atomic radius (due to it's smaller nucleus). When we consider the fact that Hydrogen gas is diatomic, Helium becomes much smaller. This is largely why it is used in leak detection instead of Hydrogen.


bretta (author)  Kiteman5 years ago
I forgot one thing. We're doing this on a budget, trying for lower than $750. Crazy yes. Unfortunately helium is $65/1000 cubic feet, which would be $910.
kelseymh bretta5 years ago
How much does the liability insurance cost, which you're going to need when you set fire to either your neighbors' houses or the city park you try to launch from? There's a very good reason hydrogen isn't used for balloons any more.

bretta (author)  kelseymh5 years ago
It didn't help that they also combined it with silver nitrate dope either. However, my case I have easily a 200 foot radius (field, not a park or back yard) for this thing to launch in, have lots of materials, such as wood, gas, and steel, but no lifting gas. We do realize what we are doing here. Hell, some current weather balloons flying use hydrogen. Now please, are there any suggestions?
Kiteman bretta5 years ago
The silver nitrate helped the fabric burn, not the hydrogen.

I have not heard of ant weather balloon using hydrogen for decades - the suggestions you are getting are the right thing to do.

You're worried about cost - how are you going to store the gas before you use it? Cryogenics will be far more expensive than helium.

Before you say "we'll generate it as we need it", that isn't going to work at the speed you want without large quantities of concentrated, corrosive, and expensive chemicals, or without a massive and expensive kit to electrolyse large volumes of water at once.

Whichever way you do this, there is going to be a cost involved.

You should instead be thinking about how to meet that cost - consider selling advertising space on the balloon (say a notice that is always visible in the field of view of the photos you take), or making it a media event, in which you always throw in the phrase "...and we're really grateful to XX for all the help they've given".
bwrussell5 years ago
What's wrong with helium? Most of these amateur weather balloon photography projects just use helium. You can rent a helium tank, it's much cheaper, and way, way safer. With two balloons I think you'd have plenty of lift.
rickharris5 years ago
1. Hydrogen is produced most easily by the reaction of acid on a metal - or Alkali on aluminium.

2. Otherwise it is produced by the electrolysis of water producing Hydrogen and oxygen .

3. All of the above warnings are valid - Hydrogen only need a small amount of energy to get it to explosively recombine with the oxygen in the air - That's not something you need

4. What happens when the balloon comes down it will still possibly have a lot of Hydrogen in it and be dangerous to anyone who finds it.

5. despite the world shortage of helium it is still the way to go - expensive though.
I dunno.  I think that works out to about 43 kg (or 95 pounds) of H2.

(43 kg)*(1000g/kg)*(mol/2g)*(22.4 L/mol)*(ft^3/28.3L) = 14 000 ft^3

I mean there are various chemical reactions that produce hydrogen; e.g. electrolysis, reacting acids with metals, strong base with aluminum, etc.
but if you really need that much of it, the most simple thing to do might be just buy 100 pounds of H2.

Places that sell gasses for welding, usually have a selection of industrial gasses, usually including H2.

Seems like there was somebody else here who was launching things into near space with weather balloons, here:
Step 8, and the comments, has some discussion on filling the balloon.