Electrolysis 2 liter bottle

[M3NT4L]

My mom recently found my 6th grade science project board on electrolysis. Please correct me if im wrong but it is a prosses in witch water is mixed with salt to increase conductivity and using an electric current you return H2O into its basic form H and O. So being as bored as i was i reconstructed this idea with a friend, well he had the idea of droping a match in the hole of the 2 liter bottle. and it sounded like it had just blown up. Well my idea was to see if there was a way to recreate the electrolysis inside a pvc cannon i just want to know if anyone has done it or if it would work. i have very little knowledge in any sort of science so please inform me... im not going to try it anytime soon if ever im solely wondering

[Darkerweb12]

You could fill your cannon chamber up about 1/8 full with water, hold it vertical and use electrodes in the bottom to electolisize (sp.) the water, it would take a long time, but it would produce BOTH hydrogen and oxygen, perfect for a nice combustion...

[FiveseveN]

Only problem is you need a pretty powerful battery. And it takes A LOT to fill a reasonably-sized chamber. There was a topic similar to this just two days ago. I believe Rambo said he tried it and scrapped the idea.

[drac]

And considering that Rambo is one of our fuel whizzes on the board with his knowledge of that stuff, it's probably a good idea not to try it unless you feel like wasting time.

[cannon freak]

Well putting salt in will help produce alot more hydrogen but the draw back is that it does not only separate the water but it also sparates the salt. So what you get is hydrogen gas off of the negative electrode and chlorine gas coming off of the positive electrode. Also the water will become more of a basic solution as the electrolosis goes on since the salt is being broken up and the sodium is reacting with the water. You could get a pretty good mix of O2 and H2 with normal drinking water since there are enough minerals in the water to allow a current but as FiveseveN said you will need a powerfull battery. You can use sodium hydroxide in place of salt, this is what Im doing for a pnematic I hope to build soon which will allow me to break the sound barriar.

You may want to have your electrolosis maching separate from your cannon and just have them connected by a hose, this would just make the gun look better and would probably just be easier than doing it directly in the chamber.

[M3NT4L]

So are there any chances of this idea to work, other than that will i blow up.

[sgort87]

You need to make sure your electrodes are Stainless Steel 316 or else the oxygen electrode will oxidize and create other gasses which will not only remove oxygen from the potential environment, but add in other gasses to clog it all up. I tried igniting a few things done with bad electrodes and it was very dissappointing.

As for using this method to fuel a PVC cannon. No! Bad! No! PVC is not made to hold the pressures caused by a hydroxy combustion. It WILL fail.

[cannon freak]

Carbon rods are good electrodes, they don't seem to deterorate except when using salt the chlorine will eventualy eat it away.

[sgort87]

No, that's exactly what you DON'T want to use when trying to make a hydroxy mix. The oxygen will cobine with the carbon and form lots of carbon dioxide in the mix.

You will notice the oxygen electrode deteriorate significantly.

[Pete Zaria]

If you're going to try this, use stainless steel 316 bolts for electrodes as sgort suggested. You should be able to get them at most hardware stores. For a power source, I suggest a motorcycle battery with an in-line fuse and volt meter. Use mineral water (the bottled stuff from the grocery store) with no added salt. The mineral content should be enough to make it conductive.
It's going to take a fair amount of water and a lot of time to produce enough hydrogen and oxygen for one shot. It's a cool concept, but I don't think doing it on-board the gun is realistic. Maybe having a tank setup to generate the hydrogen and oxygen seperately, though....

Peace,
Pete Zaria.

[sgort87]

Agreed. But make sure it is <b>stainless</b> steel <b>316</b>.

[Benny]

It takes ages to make even a small ammount, and hydrogen + oxygen has 500psi combustion pressure.

[cannon freak]

It only takes ages to make hydrogen depending on your electrolosis machine. You can make one that can produce tons of hydrogen very quickly, it will simply be bigger and use more power and will most likely have a more powerfull electrolyte.

[boilingleadbath]

Can you point to a scource for this 500 psi number?

"the carbon will combine with the oxygen and..."
Odd, because they hold up pretty well in clorate cells.
Graphite has loads of dislocalized electrons - this increases the activation energy for the reaction, in the same way it does for benzene.

On that subject, I'm going to try using aluminum electrodes.
I figure... what's the worst that can happen? It eats my electrodes?

[cannon freak]

There is another simple way to make quite a bit of hydrogen without electrolysis. You could take some water and add some sodium hydroxide to it and then throw in a few old pop cans (aluminum), you will get quite a bit of hydrogen from the reaction, although you will also get a nasty looking mixture and quite a bit of heat as well. You may also have to put the gas through a water lock to haelp remove most of sodium hydroxide fumes that may have been produced I seen this one machine that a guy made for his car and all it was was some 4" PVC and some high temperature hose. He was able to fill a balloon in about 20 seconds.