Hydrogen Harvesting

SpudsMcGee · Sat Feb 28, 2009 10:32 pm

Hiya Everybody,
If you haven't been acquainted with "Works Bombs", they are like dry ice bombs but they use The Works toliet bowl cleaner and aluminum foil balls in a soda bottle. There is a chemical reaction that creates hydrogen. Then the gas builds up pressure until the bottle goes boom.
But what I want to know is...
How should I go about harvesting the hydrogen gas in the safest way possible for use in a spud gun?

rp181 · Sat Feb 28, 2009 10:41 pm

*Works bombs* work because they are sodium hydroxide or hydrochloric acid. Sodium hydroxide (pure) is sold as crystal drain cleaner. I do not think it is worth using this as a way to get hydrogen. It is used up quickly. Look into electrolysis for a more economical way, or buy a propane tank =)

inonickname · Sat Feb 28, 2009 10:42 pm

To pressurize as per a pneumatic, or ignite in a combustion?

First you should check if it's actually just hydrogen, because in a toilet bowl cleaner you probably have peroxide, chlorine et cetera. Best way I can of is install a piece of tubing going to the inlet of a fridge compressor, and store it at around 300 psi and regulate it out as required.

But most importantly, check that it only produces hydrogen. It's very unlikely.

SpudsMcGee · Sat Feb 28, 2009 10:44 pm

Its sodium hydroxide, I did my science fair on them. The works can be bought at a dollar store, and can be used over 20 times per bottle. Why don't you think it would be economical?

Edit: Its most likely not pure, but what effects would that have on my cannons performance?

dudeman508 · Sat Feb 28, 2009 10:46 pm

If i where you i would have two chambers sepereated by a ball valve and a quick connect. Put your cleaner and tinfoil in one chamber wait for it to pressurize, close the ball valve and disconnect the quick connect.

SpudsMcGee · Sat Feb 28, 2009 10:49 pm

When the reaction happens, a lot of heat is released and I don't think that it would be very helpful to the cannon.

inonickname · Sat Feb 28, 2009 10:53 pm

SpudsMcGee wrote:Its sodium hydroxide, I did my science fair on them. The works can be bought at a dollar store, and can be used over 20 times per bottle. Why don't you think it would be economical?

Edit: Its most likely not pure, but what effects would that have on my cannons performance?

That depends, are you compressing it for use in a pneumatic or igniting it in a combustion?

In a pneumatic, probably little effect. If you're using it in a pneumatic then just hook it up to the inlet of a good compressor and pump it up and store it in an old compressor chamber or something.

In a combustion, it may be a little more degrading. A lot of chemicals are dangerous when ignited, so use good ventilation (which is usually something you don't need with hydrogen).

Personally, for use in combustions I have two old compressor tanks (medium sized) and I'm using an electrolysis unit (must build a much larger one) hooked up to a fridge compressor to pump each tank with a few hundred psi of each, then regulate it out. That's a future project though.

SpudsMcGee · Sat Feb 28, 2009 11:12 pm

It would be a combustion. And heres a link to a good video of the works bomb.

Lentamentalisk · Sun Mar 01, 2009 8:58 pm

Ok, simple solution.
I was doing similar stuff, but filling balloons, and making crude hydrogen torches.
I put it in a wine bottle, so that I could heat it up, to speed up the reaction, though once it gets going, the reaction happens quite quick. On a hot day, you might even want to stick it in a water bath to keep the temperature down. Then, the super key part, is that you MUST bubble it through water to both cool it, and to get all of the nasties out of it.

When I did this, I put the foil in long, loose rolls, to maximize sufrace area, an make the amount of foil reacting as constant during the entire duration, as possible. Next, I took a cork, drilled a hole through it, and epoxyed a rubber hose on, which leads to the bottom of a plastic water bottle. I then stuck the neck of the balloon over the mouth of the bottle. Once everything is set up, you can pour in "The Works" and quickly put the cork in.
The water becomes absolutely filthy, so you know you are doing some serious filtering.

jimmy101 · Mon Mar 02, 2009 12:44 pm

Unless you know what you know what you are doing this is not a very good idea.

You must have a pressure relief safety since in a closed system this'll develop very high pressures. In Lentamentalisk's setup the balloon is the safety. Pressurize the system to anything more than a PSI or two will pop the ballon.

If you don't have a safety release and the system explodes you have, not only hunks of glass and plastic flying about but also hot alkali.