Subject: H2O2 welder

From: [email-masked] (Ken Knaell)
Date: 29 Nov 93 15:28:57 GMT

It seems that it might be easy to build a water welder if one enclosed
a volume of water and separated the volume into two spaces above the
positive and negative electrodes to collect the H2 and O2.  One could
then use an Oxy-Acetylene torch with the handpiece valves wide open
and regulate the amount of heat by adjusting the current into the
electrolysis cell.  However one thing scares me about doing this
possibly very dangerous "build your own" water welder.

If perhaps the oxygen and hydrogen get mixed in this enclosed
space one could have an explosion.  This might happen if perhaps
one valve ont the oxy-acet handpiece was left closed and both gasses
had to exit bya single line.  If you have ever seen the fierceness
that pure oxygen lends to an otherwise placid flame this poses a
a serious threat.  To see how the temperment of such a flame changes
try pointing an oxy-acet handpiece exhaling oxygen into the base of
a bunsen burner.  The flame will jump down into the base of the tube
with a nasty pop and sound like it is trying to melt the tube.

It sounds easy but BE CAREFUL !!

////////////////////////////////////////////////////////////////////
|   KENNETH KNAELL            |   STATEMENTS MADE HERE DO NOT  |
|   CARDEROCK DIV NSWC        |   REPRESENT POLICY OF THE      |
|   BETHESDA, MD 20084-5000   |   U.S. NAVY                    |

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From: [email-masked] (James Foster x2912)
Date: Mon, 29 Nov 1993 20:54:27 GMT

In article <[email-masked]>, [email-masked] (Ken Knaell) writes:
|> It seems that it might be easy to build a water welder if one enclosed
|> a volume of water and separated the volume into two spaces above the
|> positive and negative electrodes to collect the H2 and O2.  One could
|> then use an Oxy-Acetylene torch with the handpiece valves wide open
|> and regulate the amount of heat by adjusting the current into the
|> electrolysis cell.  However one thing scares me about doing this
|> possibly very dangerous "build your own" water welder.
|> 
|> If perhaps the oxygen and hydrogen get mixed in this enclosed
|> space one could have an explosion.  This might happen if perhaps
|> one valve ont the oxy-acet handpiece was left closed and both gasses
|> had to exit bya single line.  If you have ever seen the fierceness
|> that pure oxygen lends to an otherwise placid flame this poses a
|> a serious threat.  To see how the temperment of such a flame changes
|> try pointing an oxy-acet handpiece exhaling oxygen into the base of
|> a bunsen burner.  The flame will jump down into the base of the tube
|> with a nasty pop and sound like it is trying to melt the tube.
|> 
|> It sounds easy but BE CAREFUL !!
|> 
|> 
|> ////////////////////////////////////////////////////////////////////
|> |   KENNETH KNAELL            |   STATEMENTS MADE HERE DO NOT  |
|> |   CARDEROCK DIV NSWC        |   REPRESENT POLICY OF THE      |
|> |   BETHESDA, MD 20084-5000   |   U.S. NAVY                    |

Well, that is what check valves are for, but it would take a fairly
sensitive one (a float system of some sort?) to work at the low
pressures that something like this would generate.

So how do the commercial units keep up pressure, and how much do they
use?  I can envision a sealed electrolysis unit with a water level 
sensor that pumps water in when the level falls too low.  The gasses 
would then build pressure in their respective chambers.  You could scale
the pressure ratio by how large the chambers were. Equal sized would
give 2/1 (H2/O2) which might be what you want anyway.  I imagine you'd
only need three to five psi for the thing to work okay.  I forget my 
chemistry, however.  As the pressure builds up will the electrolysis
rate decrease, or does it stay more or less constant?

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From: [email-masked] (bill nelson)
Date: Tue, 30 Nov 1993 07:40:25 GMT

[email-masked] (James Foster x2912) writes:
: 
: So how do the commercial units keep up pressure, and how much do they
: use?  I can envision a sealed electrolysis unit with a water level 
: sensor that pumps water in when the level falls too low.  The gasses 
: would then build pressure in their respective chambers.  You could scale
: the pressure ratio by how large the chambers were. Equal sized would
: give 2/1 (H2/O2) which might be what you want anyway.  I imagine you'd
: only need three to five psi for the thing to work okay.  I forget my 
: chemistry, however.  As the pressure builds up will the electrolysis
: rate decrease, or does it stay more or less constant?

Since neither O2 or H2 are particularly soluble in water, I don't think
that the rate would decrease much with pressure. At least, until it got
fairly high.

Remember that these torches use minute tips - about the size of a hypodermic
needle. I doubt if more than a pound or so of pressure would be necessary.

Bill

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From: [email-masked] ([email-masked] (Greg Young))
Date: 30 Nov 1993 17:09:08 GMT

In article <[email-masked]>,
>needle. I doubt if more than a pound or so of pressure would be necessary.

Right, the decrease in electrolysis rate over the pressure range of 
interest would be negligible.

The minimum usable pressure would be a function of flame velocity. 
The pressure has to be high enough that the gas velocity through
the tip exceeds the flame velocity of H2/O2, which is pretty high.
Otherwise you get a flashback.  I hate flashbacks.

Pressurization of the gasses could be managed by a pressurized 
reservoir attached to the electrolysis chamber.  An air pressurized
water reservoir about 10X the volume of the chamber should work if
half the volume is airspace.  This would keep the pressure drop 
within reason.

Initiate guesstimation mode -- Check assumptions before using

A standard O2 bottle contains about 300 cu.ft. at STP.  If a long
work session uses 10% of a bottle of O2, that's 30 cu.ft. or about
1400 ml of H2O electrolyzed.  With a 500 ml chamber and a 5 liter
reservoir half filled with water, the pressure drop over the run
would be from 5 psi to 3.5 psi. Whether this would be acceptable
I don't have the experience to judge.

Control of the electrolysis rate could be accomplished using
cylindrical or tapered electrodes.  As gas builds up the water will
be forced into the reservoir and the working length of the electrode
will be reduced, reducing the rate of gas production.  Some 
experimentation would produce a good electrode geometry.

Since water electrolyzes at about 1.5V, a 3 volt supply should
do a good job if the water has some salts in it.  The current 
requirements can be calculated.  The low voltage reduces the 
possibility of sparks in the chamber.  Sparks in the chamber would
be a BAD thing.

The problem I don't see a way around is the need to get the mixture
at the torch perfect.  If you don't get a perfect mixture then  
hydrogen or oxygen builds up in the cell, since electrolysis produces
exactly two volumes of H2 per volume of O2.  The electrode geometry
could eliminate the possibility of mixing in the chamber by shutting
down the electrolysis, but the torch is going to go out.  A floating
ball type valve could keep water out of the hoses when this happens,
but an unplanned shutdown could be a real pain.

Feed me an interesting idea and I can ramble for hours.  I'll shut 
up now.  

Disclaimer -- H2 and O2 do very energetic things when mixed.  Making
	      an apparatus like the one under discussion could be
	      very hazardous to your health.  Explosions may ensue.
	      These ramblings are those of the author alone and are not
	      in any way, shape, form, or fashion official policy
	      of the University of North Carolina.  Okay, Lori?

Did I forget anything important?

Greg  AC4YT
[email-masked]

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From: [email-masked] (Jim Berilla)
Date: 1 Dec 1993 06:01:56 GMT

A friend of mine has such a torch.  I forget the name of the manufacturer,
but the list price is about $1200.  A few comments about it that I haven't
seen here yet:

It uses a single electrolysis chamber, with the hydrogen and oxygen collecting
mixed above the water + potasium hydroxide electrolyte.  The manufacturer
claims that the chamber is strong enough to withstand an explosion of the
gasses in the chamber.  The chamber is made of about 3/8" thick stainless
steel.  The power supply cycles on and off to maintain pressure.

The gasses are carried from the generator to the torch with a single 1/4"
ID PVC tube.  The tube on his is apparently the original tube, and doesn't
seem to be the anti-static variety (which has a black stripe running along
the side).

There is no way to control the mixture.  The flow is regulated by a knob
on the torch handle.

It is very nice to use.  A dream on small work.

-- 
      Jim Berilla / [email-masked] / +1 216 368 6776

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From: [email-masked] (Michael Moroney)
Date: Wed, 1 Dec 1993 08:15:29 GMT

I've heard of an interesting variation on an H2/O2 torch.  In this torch the
H2 is passed through an electric arc converting it into atomic hydrogen (H).
This is burned with the O2, and the heat of combustion of atomic hydrogen
is much higher than that molecular hydrogen, and the torch is rather hotter 
than oxyacetylene.  

(instead of 2H2 + O2 = 2H2O the reaction is 4H + O2 = 2H2O)

-Mike

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From: [email-masked] (Ralph Snel)
Date: Wed, 1 Dec 1993 16:01:34 GMT

> (instead of 2H2 + O2 = 2H2O the reaction is 4H + O2 = 2H2O)
Sounds almost like a plasme burner to me: take an appropriate microwave
and any (inert) elemental gas like N2, zap it with the microwaves and
pump it out of the chamber before the electrons and ions recombine. Gets
you up in the 10000 K range.

Ralph

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From: [email-masked] (Mike Folenta)
Date: 1 Dec 93 16:31:31 GMT

[email-masked] (Michael Moroney) writes:
|> I've heard of an interesting variation on an H2/O2 torch.  In this torch the
|> H2 is passed through an electric arc converting it into atomic hydrogen (H).
|> This is burned with the O2, and the heat of combustion of atomic hydrogen
|> is much higher than that molecular hydrogen, and the torch is rather hotter 
|> than oxyacetylene.  
|> 
|> (instead of 2H2 + O2 = 2H2O the reaction is 4H + O2 = 2H2O)
|> 
|> -Mike

     Weeeeellllll, I don't really think so!!!

     How long (time wise or distance from the arc) do you think that the
 atomic hydrogen is going to stay as a monomer?

     Molecules which as typically found as dimers (N2, O2, H2, etc) are
 that way because the base atoms are SOOOO reactive that as soon as they
 see or get near ANY other atom, they react (bind).  And the most likely
 atom around when you split H2 is another H.  And then they rebind and are
 more stable and the universe goes on.

     Yeah, monoatomic hydrogen would be VERY reactive. :-}

     But why do we need to try and get an atomic hydrogen torch?  We were
 just looking for a small, clean torch originally for jewelry work.

-- 
       ***** These are my opinions.  Get your own. :-) *****
      Michael Folenta          | U.S. Army ARDEC
   Future Weapons Branch       | Picatinny Arsenal, NJ 07806-5000
  email [email-masked] | (201) 724-3791  [DSN 880-3791]

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From: [email-masked] (Bob Neidorff)
Date: Thu, 2 Dec 1993 13:58:29 GMT

I guess all of this H2O stuff has got me thinking.

Wouldn't it be cheaper to use a normal oxy-acetylene torch on an
Oxygen and a Hydrogen bottle?  Hydrogen can't be as expensive or
as unstable as acetylene, and it seems like, from the costs 
mentioned so far, that oxy-acetylene rigs are cheaper than these
water torches.

What am I missing?

And you thought this stuff was dangerous enough.  Now you got me
thinking!  :-)

-- 
Bob Neidorff; Unitrode I. C. Corp.  |  Internet: [email-masked]
7 Continental Blvd.                 |  Voice   : (US) 603-424-2410
Merrimack, NH  03054-0399 USA       |  FAX     : (US) 603-424-3460

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From: [email-masked] (Knaell)
Date: 2 Dec 1993 10:59:29 -0500

In rec.crafts.metalworking, [email-masked] (James Foster x2912) writes:
							I imagine you'd
>rate decrease, or does it stay more or less constant?

I imagine that it would only take a slight pressure also since one could
run the torch with the handpiece valves wide open.  The stoichiometric
mixture of two volumes of hydrogen to one of oxygen to produce a neutral
(not oxidising or reducing) flame would be insured since the gasses
came from neutral water.  The pressures would be approximately equal
if the electrolysis took place in oneenclosed volume with only a slight
pressure head of water between the H2 and O2 collection chambers.

The thought occurs to use two plastic 1 liter soda bottles to minimize
explosion hazard and to be able to see the water levels.  These would
be connected by a water bridge as showen.  The electrical current to
stainless steel electrodes could be made through the same metal tubing
used to withdraw the gas.
	 +V           -V
	  .            .
	  .            .
      ____.            .______
   <- ___ \            / ____ ->
  gas    \.\          /./   gas
	 |.|          |.|
	 |.|          |.|
	 /.\          /.\
	/ . \        / . \
       |  .  |      |  .  |
       |  .  ________  .  |
       |  .  ________  .  |
       |  -  |   ^  |  -  |
       \_____/   |  \_____/
		 |
		 |
	     water bridge

I think 1 liter of water lould supply enough gas for most of my welding
jobs.

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From: [email-masked] (David Hoopes)
Date: 2 Dec 93 12:56:22 GMT

[email-masked] (Mike Folenta) writes:

[stuff deleted]

> just looking for a small, clean torch originally for jewelry work.

More power!!!!

-- 
---------------------------------------------------------------------
David Hoopes                              Exabyte Corp.
[email-masked]                       11100 W 82nd St.          
Voice: (913) 492-6002 x3323               Lenexa, Ks  66214

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From: [email-masked] (Michael Moroney)
Date: Fri, 3 Dec 1993 06:52:50 GMT

> atomic hydrogen is going to stay as a monomer?

That's what I thought until I first read about it.  This is what the McGraw
Hill Encyclopedia of Science and Technology has to say:

"...Atomic hydrogen is also produced when an electrical discharge is passed
through hydrogen gas at low pressure or when a mixture of hydrogen and
mercury is irradiated with light of wavelength 2537A from a mercury arc.
...
The heat released when hydrogen atoms recombine to form hydrogen molecules
is used to obtain very high temperatures in atomic hydrogen welding."
[hmm, no mention of O2 used in such a torch.  Maybe they don't bother
(heat of 2H -> H2 releases almost twice as much energy as H2 + 1/2 O2 ->
H2O)]

>     Yeah, monoatomic hydrogen would be VERY reactive. :-}

"Atomic hydrogen is a powerful reducing agent, even at room temperature.
It reacts with oxides and chlorides of many metals including silver, 
copper, lead ... reduces some Na and K salts to the metallic state...
reacts with a number of elements to yield hydrides.

-Mike

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From: [email-masked] (Neil R. Marsh)
Date: 2 Dec 1993 22:12:41 -0800

> Oxygen and a Hydrogen bottle?  Hydrogen can't be as expensive or

        As I understand it, hydrogen is a real SOB to store; atoms are
so small they sneak through seals, threads, and such.  The only way to
make it stay put is to bind it with some other element, like oxygen,
and that brings us right back to water.

--
------------------------------------------------------------------------
Neil Marsh  [email-masked] -or- [email-masked]  Chehalis, WA USA

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From: [email-masked] (John De Armond)
Date: Sat, 04 Dec 93 06:32:37 GMT

>and that brings us right back to water.

Not really.  Even though the hydrogen atom is the smallest, that it 
is diatomic means the molecule is too large to diffuse to any
great degree.  Now helium, that's another matter.  At my welding
supply store we DID have to watch the shelf-life of our helium
cylinders in order to minimize diffusion loss.

The reason one would want to use a H/O generator is simple.  The
machine capable of running a jewelry-sized torch is scarcely larger
than a small toolbox and is easily carried in one hand.  With the
machine, one does not have to lug a couple of cylinders around,
doesn't have to buy or lease them, doesn't have to hassle with 
driving to the welding store for refills and there is no worry of
running out in the middle of a job.

John

-- 
John De Armond, WD4OQC                   | For a free sample magazine, send
Performance Engineering Magazine(TM)     | a digest-size 52 cent SASE 
Marietta, Ga     "Love America"          | (Domestic) to PO Box 669728
[email-masked]    "Hate its government"   | Marietta, GA 30066
Email to me may be published at my sole discretion.

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From: [email-masked] (Scott Cannoy)
Date: 4 Dec 93 05:08:11 GMT

>and that brings us right back to water.

Hydrogen is stored the same way as compressed oxygen. Many Jewelers, glass
workers, and plastics people use Oxy/hydrogen flame for their work 
because of the cleanliness (no stray carbon particles to mess up their work).

Contact your local welding supply house about using your existing oxy/acety
torch with hydrogen as a fuel gas. I know with Victor Equipment you are 
able to use the same tips for both fuels. You will have to buy a 
regulator for hydrogen, as the one you use now for acetylene will not 
handle the 2000psig that hydrogen is stored at.

Scott

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From: [email-masked]
Date: 4 Dec 93 13:52:21 -0500

> (instead of 2H2 + O2 = 2H2O the reaction is 4H + O2 = 2H2O)

I have seen this referred to (in VERY old chemistry textbooks) as 
"Langmuir's atomic hydrogen blowtorch" -- I'll try to dig up the reference 
if anyone is interested.  I seem to remember that the arc was struck 
between carbon electrodes and the arrangement gave temperatures in excess 
of 2000 C
Sidd

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From: [email-masked]
Date: 4 Dec 93 13:56:57 -0500

> and that brings us right back to water.

Does the hydrogen stored in hi-pressure tanks gradually seep out ?
We use these tanks in the lab sometimes. Do I have to worry about 
pressure loss and what is the time scale over which such a loss
would occur ?

Sidd

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From: [email-masked] (James Foster x2912)
Date: Mon, 6 Dec 1993 01:33:27 GMT

In article <[email-masked]>, [email-masked] (John De Armond) writes:
|> [email-masked] (Neil R. Marsh) writes:
|> 
|> >        As I understand it, hydrogen is a real SOB to store; atoms are
|> >so small they sneak through seals, threads, and such.  The only way to
|> >make it stay put is to bind it with some other element, like oxygen,
|> >and that brings us right back to water.
|> 
|> Not really.  Even though the hydrogen atom is the smallest, that it 
|> is diatomic means the molecule is too large to diffuse to any
|> great degree.  Now helium, that's another matter.  At my welding
|> supply store we DID have to watch the shelf-life of our helium
|> cylinders in order to minimize diffusion loss.
|> 
|> The reason one would want to use a H/O generator is simple.  The
|> machine capable of running a jewelry-sized torch is scarcely larger
|> than a small toolbox and is easily carried in one hand.  With the
|> machine, one does not have to lug a couple of cylinders around,
|> doesn't have to buy or lease them, doesn't have to hassle with 
|> driving to the welding store for refills and there is no worry of
|> running out in the middle of a job.
|> 
|> John
|> 

Would something like the "Little Torch" mentioned recently be
suitable for running on H2/O2?  I called Smith and found that
the place I get my tanks from handles them, though I haven't
had the time to get over there and take a look at one.