Hydrogen Powered Mini?

[KurlyQ]

So, I've been tossing the idea of making a hydrogen powered spud gun around in my head for a while, and I've even made a few prototypes, but they never seem to be reliable.
Making a mini cannon seemed to be my only reasonable way to go about this for three reasons:

1: less hydrogen takes less time to make
2: if a mini cannon explodes, it won't be as dangerous as a large one
3: I don't have much money to buy large parts

I use electrolysis to generate my hydrogen, just because it's easy, safe, cheap, and on demand.
The reason I'm posting here is that I'm looking for some ideas for materials to make a new and awesome cannon out of.
I have a quick picture below that outlines my current idea, but it needs some improvement.


any ideas?
anything is welcome

[inonickname]

Oh god..I swear I've already done something that reminds me of this..

I'm going to say straight up, don't use plastic. Metals are the way to go, I used aluminum, brass and stainless on mine. I'd also recommend to not have the electrolysis system in your gun, as if it explodes it not only cuts you up, but you spill a caustic liquid on your hand. Also, the use of a decent electrolyte will result in corrosion of metal chambers.



If you use metals that are vulnerable to hydrogen embrittlement then varnish your gun.

[KurlyQ]

that's an awesome cannon. I'll have to look into getting some metal parts soon. thanks for the inspiration

[jimmy101]

Might take a look at;
1. http://sci-toys.com/scitoys/scitoys/ech ... .html#bomb
2. google "Estes hydrogen rocket"
3. http://www.et.byu.edu/~wheeler/benchtop/pumpkin.php and http://www.et.byu.edu/~wheeler/benchtop/pumpkin2.php

In a gun, there are a couple challenges. Inonickname pointed out several of them. In addition, if the electrolysis is "on board" then you have problems keeping the spark (ignition) electrodes dry enough to operate. You also have to have a way to deal with the pressure build up that occurs as the hydrolysis progresses. Doesn't take much pressure to pop the ammo out'a tha barrel without even igniting the mixture.

[inonickname]

Here's another hint: Fire it right after you fuel it, as hydrogen is happy to find any leak you never thought existed.