Hydrogen/electrolysis ratios

[inonickname]

Well after the Mini advanced buildup I've been searching for another project. So for now, I've decided to settle on rebuilding a similar cannon, except rebuilt to run on hydrogen.

The first thing to do is construct the electrolysis unit, something like this except on a much smaller scale, and using carbon electrodes. Accord into the combustion wiki the correct ratio for hydrogen is 2H2, O2 for combustion (also obvious seen as water is H2O..). So the main question with that is if I should allow the hydrogen and oxygen to mix in the elect. unit, then pump it into the chamber, or collect and pump them in separately.. I'm away that having a perfect mix for combustion in the unit is dangerous, but precautions will be taken.

And secondly, the chamber. As you have a near perfect mix being pumped in, you could try purge the air from the chamber but it would be difficult. As far as I know hydrogen has a much larger scope for combustion than propane or butane, so is it possible just to purge as much of the chamber gas as possible, then ignite the hydrogen/oxygen/ nitrogen-oxygen-argon(?) mix? I'm also considering trying to get the chamber airtight (burst disk) then using a syringe with a check valve to try create a vacuum, then inject the hydrogen oxygen mix, but it's a lot of effort for one shot.

The gun will be rebuilt with the lowest rated parts hopefully being beyond 200 psi (I understand H2/O2 combustion is around 180ish?), using shock resistant materials. Will have spark strip, chamber fan..all the stuff the original had (still in a 1/2" chamber).

Any thoughts/input/questions/answers?

thanks guys

[rp181]

Do not use carbon electrodes. some oxygen will combine and give you carbon dioxide. Use plain steel (NOT galvanized) in sodium hydroxide. The plates always stay clean. If you want to go this way, look for crystal drain cleaner in the hardware store. If it has warnings on contact with aluminum and wood, its correct. To test, put some in water, and drop AL foil in.

Also, do not use glass. NaOH reacts slowly with it. PVC takes on a yellow color, but it works fine.

[TurboSuper]

Vaccuuming out the chamber seems a bit excessive- HHO is pretty voltatile stuff, you shouldn't have any trouble getting it to react.

[jon_89]

That is a pretty big electrolysis machine, you could go alot smaller than that. There are several videos on you tube on making a electrolysis machine. You have a fan to fit in a .5 inch chamber?

[inonickname]

Something like this perhaps?


RP, how much CO2 do you assume would be produced per volume of hydrogen/oxygen.. Hydrogen has a massive combustive range, something like 5% to 75%, so unless it's a large amount of gas I'm not worried about it. I'd really rather to stay away from caustic/corrosive liquids.

Thanks for the input guys, I'm going to put together a prototype soon. If all goes well and I get some nice super volatile mixture I may do a how-to on electrolysis for mini's..

Thanks guys

8)

[ramses]

well you would be better off using NaOH than salt, because salt produces chlorine gas and chlorates (oxidizing salts, big fun) under the right (wrong?) conditions.

good luck

[john bunsenburner]

Yes you should definately use either NaOH, KOH or perhaps citric acid if you are concerned, just not table salt. Sodium bicarbonate(baking soda) was said to bring pleasing results too. I agree to rp about using plain steel electroded(or platinum, titanium or any other metal that doesnt easyly corode, perhaps gold).

persoanlly i am not a far of electrolosis as it consumes far more energ than it gives and takes too long for me. I prefer taking highly concentrated lye and putting aluminium cans in which produce H2 gas and then using O2 bulk tanks and then mixxing the gasses to obtain HHO gas. Just my two cents.