From: tceisele@mtu.edu (Eisele)
Subject: Re: Hydrogen/Oxygen bombs with electrolysis
Organization: Michigan Technological University
Date: Thu, 31 Dec 1992 21:49:12 GMT

After reading Ari Jarmala's recipe for H-bombs, I thought it would be good
to post my design for a chemical hydrogen generator (the purpose is
different, with the chemical hydrogen being best for buoyancy, while Ari's
electrolytic hydrogen will make a better bang :-)  Anyway, here it is:


Materials: Reactants--Sodium Hydroxide (Red Devil Lye is good) -2 parts
		      Aluminum (Heavy aluminum foil, printer plates from
			the local newspaper, or shredded pop cans) -1 part
		      Water (warm) -16 parts
	   Parts--A reactor vessel. A piece of 4" (10 cm) diameter heavy-
			wall PVC pipe, with a flat end-cap on one end,
			and a screw-cap on the other, works nicely.  A
			stainless-steel pressure cooker is also good. 
			(one of those Bakelite microwave pressure cookers 
			would be nice, too).  Aluminum pressure-cookers
			are right out, for obvious reasons.
	          Two lengths of PVC pipe (2" diameter or more, each
			about a foot long), with flat end-caps for the 
			bottom of each, and screw-in plugs for the tops.
		  Several feet of Tygon or vinyl tubing (about 1/4" to 1/2"
			diameter) and five matching brass hose-barbs (one
			outlet for the reactor, and an inlet
			and outlet for each small PVC pipe)
		  A garbage bag, for collecting the gas
		  A small pump, that can suck the hydrogen out of the 
		  	garbage bag, and develop enough pressure to
			inflate a balloon.  I use a small rubber-bulb
			balloon pump that is made for inflating those
			balloons that clowns twist into animals.  A pump
			for a blood-pressure cuff would work good, too.

Construction:  First, make sure the reactor is gas-tight, or you are likely
to lose a lot of gas later.  Screw in the outlet barb, high enough that
splashing liquid in the reactor isn't likely to reach it.  A safety valve
might also be a good idea (drilling another hole, and putting in a cork or
a pressure-cooker safety valve, should do it).  For the first small PVC pipe,
put both the inlet and the
outlet at the top (this pipe is to catch the slopover when the reactor boils
over, which it will do if it is overloaded).  The barbs can be screwed
directly into holes drilled in the PVC pipe, and will make a good,
gas-tight seal quite easily if the hole is just a touch smaller than the
threads on the barb.  Run a length of tubing from the reactor to
the first pipe.  For the second pipe, put the inlet at the bottom, and the
outlet at the top (this pipe is a scrubber/chiller, to condense out the
steam and scrub out the alkali vapors).  Run another length of tubing from
the first pipe to the bottom of the second pipe, and run another length
from the top of the second pipe to the mouth of the garbage bag.  Put the
intake hose for the balloon pump into the mouth of the garbage bag as well,
and tie off the bag tightly. So, you will have something like this:

Reactor		Trap		Chiller 	Bag
_________	____		____		__________________________
|       |______|    |____      |    |___________|			|
|	|      |    |    |     |    |		|			|
|	|      |    |    |     |    |           |                       |
|       |      |    |    |     |    |           |   			|
|	|      |    |    |     |    |           \                       /
|       |      |    |    |     |    |            \                     /
|       |      |    |    |     |    |             \                   /
|       |      |    |    |     |    |              \                 /
|       |      |    |    |     |    |               \               /
|       |      |    |    |     |    |                \             /
|       |      |    |    |     |    |                 \           /
|       |      |    |    \_____|    |                  \         /
|_______|      |____|          |____|                   \_______/__pump>

Operation:  First, fill the chiller pipe about 1/3 full of cold water or
crushed ice, and cap both it and the trap tightly.  Then, add about 1 ounce of
aluminum, 2 ounces of lye, and 16 ounces of warm water to the
 reactor, and quickly close
the lid.  It is a good idea to wear safety glasses while doing this,
because sometimes the lye spatters.  Now, just wait.  The warmer the water
is you start with, the faster things get going.  
	The reaction will be really slow at first, but it will gradually
heat itself, and take off about the time the water starts boiling.  If you
add more than about an ounce of aluminum to the reactor, the pressure
will really ramp up, and a lot of boiling, caustic solution will boil over
into the trap until so much water is lost that the reaction slows
down, so don't get carried away.  If you start with cold water in the
reactor, you might have to wait 15-30 minutes, but if you start with hot tap
water it will get going in about 5 minutes.
	An ounce of aluminum will make about 30 liters of hydrogen, or
a little over a cubic foot.  A liter of hydrogen has a little over a gram
of buoyancy, and by an interesting coincidence, a 5" diameter balloon
weighs about a gram, and holds about a liter, so any round balloon bigger
than this will float very nicely for some time
	When the reaction stops, it is best to take the pot outside to dump
it out, because when you open it the steam is pretty caustic, and chips of
unreacted aluminum might plug your drain if you try to pour it down the
kitchen sink.
	This is great fun at parties, and is not as dangerous as you might
think, because it burns so fast that it doesn't have time to light anything
else. The burning gas tends to rise up away from the furniture and family
pets, and since it is pretty much pure hydrogen, it burns rather than
exploding, so it has a really weak concussion. A small party balloon has no
more of a blast than from, say, a small firecracker.  If you are holding
one in your hand when it is lit, it will burn all the hair off your hands
and scare the hell out of everybody, but that's about it :-)  It is still
better just to use them for their buoyant qualities though, at least
indoors.
	The only problem I have is this: After filling a garbage bag with
hydrogen, the obvious thing to do is to let it go outside, at night, with a
lit fuse.  Unfortunately, cannon fuse just seems to melt a hole in the side
of the gasbag without lighting it, because it doesn't burn with an open
flame. Other things we've tried as fuse, like cotton string, won't stay lit
on a free-floating balloon because the flame doesn't get enough fresh air.
Anybody have any other suggestions?


Tim Eisele
tceisele@mtu.edu

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Tim Eisele     Michigan Tech. University   tceisele@mtu.edu