HHO Generator

[Mikebits]

Relax, this question is not about powering a car. My wife needs to make a presentation for a bunch of teachers at a seminar. The topic, how to get kids excited about science. She asked me if I had any idea's on a demo science presentation that would go out with a boom.

Naturally the word boom struck a chord, Muhahahaa Anyways, I am thinking make a hydrogen generator and light the sucker after a bit. So I made a simple setup and tested. See attached photo for setup.

Equipment setup. Power source 14 V 1 amp supply.
Little gauge wire with alligator clips.
Used salt for electrolyte
Nickle and penny for terminal plates

What we did for testing. Attached a match to a meter stick, lit it and held flame to balloon that collects the H2 gas. Got a few good flames and pops. A few problems presented themselves.

Took about 20 mins to make enough gas. ( Can I speed this up?)
After 2 experiments 1 wire assembly failed, looked like the wire decomposed. (I am sure the small gauge wire was problem but have not metered out the setup yet.)

Any suggestions to make the experiment faster and more reliable?

Thanks


**broken link removed**

 

[Hero999]

You could use carbon rods which should not be corroded as easily, try pencil graphite.

You could buy a simple analogue meter with a dial to make it look better.

 

[Boron]

The graphite is definitely a better way to go, I've used it myself before and it doesn't corrode, just like Hero999 said. It's also less reactive than the copper I believe and so should produce better amounts of pure hydrogen.

The only thing you should look out for is that if you use too much salt, instead of a base as an electrolyte let's say, you risk creating small quantities of chlorine gas.

Only ways I know of to speed it up are to add slightly more salt (if you have a small amount) otherwise you need to increase the current.

 

[Speakerguy]

I think you will want to use lower voltage. Won't 14V be enough to start liberating Cl2 gas from the NaCl as well? I'd keep the voltage below that reaction potential (whatever it is).

 

[Mikebits]

You could use carbon rods which should not be corroded as easily, try pencil graphite.

You could buy a simple analogue meter with a dial to make it look better.

Today I tried some pretty thick pencil leads that I bought. I had 12v running around 320ma through H2O, Acetic acid, and NaCl and very few bubbles. It seemed as though the nickel/copper plates worked better.
Once again, my wire connections at the alligator clips corroded. Any ideas to keep the corrosion off the wire and clips?


I guess I need to take some real data. Here a latest image, you can see the water exploding out, sorry the flash was hard to catch.

**broken link removed**

 

[tcmtech]

What I use is stainless steel for both electrodes and sodium hydroxide for the electrolyte. Red Devil drain cleaner 100% NaOH. I have never had problems with clean stainless steel breaking down or reacting with the NaOH either.

Regardless of how much power you put to it the sodium is by nature a liquid or solid in the working limits of this type of system so it stays in the cell and will not out gas.

 

[Hero999]

Yes, I recommend NaOH because it doesn't give off any poisonous gasses, just oxygen and hydrogen and it doesn't become depleted.

The only disadvantage is the solution is caustic but the same is true for NaCl which forms NaOH during electrolysis.

What about potassium nitrate? I know it's less corrosive than NaOH and that it only produces oxygen and hydrogen. Maybe it's the best chemical to use?

I found the site below using Google.
Electrolysis

 

[tcmtech]

I will take caustic and easy to wash off of my skin over toxic and having my lungs dissolve if I breath it in.
Sodium hydroxide is farily forgiving to short term skin exposure while chlorine gas is not forgiving to any type of exposure.

Potassium hydroxide is also common in a few drain cleaners too.

 

[Ghost of the Shadows]

Once again, my wire connections at the alligator clips corroded. Any ideas to keep the corrosion off the wire and clips?

You need to take a metal that is non reactive.

Platinum is the best electrode you could ever have, but it's costy.
Stainless steel results in a oxyded ferous solution, that you should never flush in the toilets, but maybe in your plants and lawn.

And the more amperes, the more bubbles you'll get.

Say you want a torch, you need about 24A at low voltage like 5V, for best results.

Computer power supplies can supply that.

 

[Menticol]

Why you don't use a computer power supply Mike?

The old ATX's are rated at 12V 10A, or 5V 20A. In case of short circuit, it shuts off. Very nice and cheap as dirt.

Don't forget that the experiment should be easily replicable, so all the teachers and the kids can assemble it. Using pencils (with the eraser removed, the graphite exposed on both sides) are very simple electrodes. They can make a competition, to find who can make the best water / salt combination to get more hydrogen

 

[Mikebits]

Thanks for all the replies. This demo is not something the kids would be doing, only the teachers. Actually this demo was done by teachers for other teachers. The point being that science can be fun and a way to excite teachers to make science learning fun for children. The demo came and went and worked out quite well, I used much larger gauge wire than in original setup, two beefy alligator clips and some nickles, all worked well and came off with a bang. This demo was in conjunction with a week long San Diego Science Festival where I participated. Here is a pretty good pic of our Petco park where the big day was held. I think we had about 100,000 people show up to learn about science.

**broken link removed**

And to give you an idea of the crowd at one of our booths. Our topic was DNA, tough concept to teach kids.

**broken link removed**

 

[Ghost of the Shadows]

I guess so. It's pretty interesting.

I found very interesting the production of hydrogen when I put a batterie in salty water one day, didn't know what I was gonna do... that catched my attention so much that I wanted to make an hydrogen welder afterwards to cut stuff .