HHO Gun possibility?

Boom! The classic potato gun harnesses the combustion of flammable vapor. Show us your combustion spud gun and discuss fuels, ratios, safety, ignition systems, tools, and more.
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boyntonstu
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BoyntonStu
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Sun Jun 28, 2009 7:52 pm

:shock: I think that will become popular soon!
Where can I get one??? 8)
BTW, what you called a "membrane" we usually call a burst-disc.LOL
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Sun Jun 28, 2009 8:56 pm

I don't quite get the point. The concept is well known in laboratories and chemical storage facilities. It's called a blast door. Typically, they are large steel doors mounted in the ceiling and held shut by shock aborbers. If an explosion occurs the doors open. Basically the doors are the "membrane" or "burst disk". The ones I've seen typicall cover perhaps 1/2 the total floor area of the room being protected. In other words, to work they must be able to vent a huge amount of air very quickly.

To get it to actually work in the real world you need to spend some time figuring out the required vent area. That 1" ID pipe won't help much if you've get a flame propagating back into a gallon size tank of HHO. (Gawd I hate that term, it's a mixture of H2 and O2, why do people insist on made up names for things that have been known for hundreds of years?)
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boyntonstu
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Sun Jun 28, 2009 9:05 pm

jimmy101 wrote:I don't quite get the point. The concept is well known in laboratories and chemical storage facilities. It's called a blast door. Typically, they are large steel doors mounted in the ceiling and held shut by shock aborbers. If an explosion occurs the doors open. Basically the doors are the "membrane" or "burst disk". The ones I've seen typicall cover perhaps 1/2 the total floor area of the room being protected. In other words, to work they must be able to vent a huge amount of air very quickly.

To get it to actually work in the real world you need to spend some time figuring out the required vent area. That 1" ID pipe won't help much if you've get a flame propagating back into a gallon size tank of HHO. (Gawd I hate that term, it's a mixture of H2 and O2, why do people insist on made up names for things that have been known for hundreds of years?)
Vent area? Gallon tank? 1" pipe.

None of these apply.

Electrolysis separates H2O into 2H and O, hence HHO. (no biggy)

You charge the chamber with HHO, close the valve and ignite it.

You make the HHO in your garage or anywhere you have a car battery handy.

The idea is to create a pressure vessel powered by HHO.

No propane ,Butane, Mapp gas, or hairspray.

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...The idea is to create a pressure vessel powered by HHO.

No propane ,Butane, Mapp gas, or hairspray.

BoyntonStu
Been done here before (can't find it now) there was a mini in stainless steel. (and others(?))
Hydrogen hasn't been too popular because of it's rapid heat loss (high velocity but low volume(?)) IIRC,
and fears of hydrogen "imbrittlement" (small bubbles forming in steel) which can be avoided with the right metals.

From the looks of vid, seems like it could push a BB to high velocity(?)
I find hydrogen interesting myself 8)
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Mon Jun 29, 2009 1:01 am

boyntonstu wrote:Electrolysis separates H2O into 2H and O, hence HHO. (no biggy)
BoyntonStu
If it's no biggy then you won't mind calling it what it is...H2 and O2. Electrolysis is a relatively common knowledge procedure learned in 8th or 9th grade Physical Science class.

HHO is a made-up term by non-scientists to try to convince the ignorant masses that it is some breakthrough technology that has only made itself known in recent times....not true.

It actually seperates into 2H2 + O2...and while it's possible to use in a spudgun, it has generally been discouraged because of the danger of handling and volitility. For hobbyist spudgun usage, you can't beat Propane/MAPP for being the perfect combination of safety, convenience, power, clean burning, and affordability.
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Mon Jun 29, 2009 3:22 am

Yep.

I've even made an oxy-hydrogen fueled mini..

And starman is correct, HHO is a completely incorrect, and made up by idiots trying to market fuel systems which will "increase economy" - which then goes against the laws of thermodynamics. You don't get more power out than goes in.

You need a suitable chamber for it, as hydrogen has an extremely rapid burn rate. Add in oxygen and you go even closer to the sound barrier (bad). If you are to do it, VERY strong chamber and minimalize turbulence.
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Mon Jun 29, 2009 11:16 am

Sign me up as another who sees the term "HHO" and immediately writes off the person using it as an idiot(*).




(*) Exception for usage wherein the person using the term is trying to educate the afore mentioned idiot.
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Mon Jun 29, 2009 11:49 am

BTW, anyone interested in a store bought "HHO" (aagh, even Estes knows not to call it HHO) powered rocket might want to take a look at http://www.estesrockets.com/rockets.php?pid=001876
With a bit'o plumbing it could probably be used to fuel a spudgun. It's described as hydrogen fueled, which it is, but it also uses the generated O<sub>2</sub> as the oxidizer. Look up the patent for more details. The use of citric acid as the electrolyte is much safer than the often used lye or table salt. I wonder what the electrodes are made of?

BTW2, if anyone is interested in a large scale homebrew H<sub>2</sub> + O<sub>2</sub> launcher take a look at http://www.et.byu.edu/~wheeler/benchtop/hydropyro.php and http://www.et.byu.edu/~wheeler/benchtop/pumpkin2.php. Single step through the launch video on the second link.
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Mon Jun 29, 2009 4:17 pm

jimmy101 wrote:BTW, anyone interested in a store bought "HHO" (aagh, even Estes knows not to call it HHO) powered rocket might want to take a look at http://www.estesrockets.com/rockets.php?pid=001876
With a bit'o plumbing it could probably be used to fuel a spudgun. It's described as hydrogen fueled, which it is, but it also uses the generated O<sub>2</sub> as the oxidizer. Look up the patent for more details. The use of citric acid as the electrolyte is much safer than the often used lye or table salt. I wonder what the electrodes are made of?

BTW2, if anyone is interested in a large scale homebrew H<sub>2</sub> + O<sub>2</sub> launcher take a look at http://www.et.byu.edu/~wheeler/benchtop/hydropyro.php and http://www.et.byu.edu/~wheeler/benchtop/pumpkin2.php. Single step through the launch video on the second link.
Thanks,

Good information.

http://www.et.byu.edu/~wheeler/benchtop/pumpkin2.php

Does not work for me.

Tiny?


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Mon Jun 29, 2009 5:44 pm

boyntonstu wrote: http://www.et.byu.edu/~wheeler/benchtop/pumpkin2.php

Does not work for me.

Tiny?
Try it again, it works OK for me in all three browsers I use.
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boyntonstu
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Mon Jun 29, 2009 6:07 pm

jimmy101 wrote:
boyntonstu wrote: http://www.et.byu.edu/~wheeler/benchtop/pumpkin2.php

Does not work for me.

Tiny?
Try it again, it works OK for me in all three browsers I use.
Yep!

Worked just fine.

BoyntonStu

Disclaimer: I am an idiot for using the term 'HHO' instead of H2 an O2..

It was http://www.hhoforums.com where I began to use this horrible term. So sorry.

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john bunsenburner
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Mon Jun 29, 2009 6:22 pm

Alternatively it can be called browns gas, I am not sure why but its been used. HHO is incorrect as people said. The process is misleading though seeing as how one would expect H<sub>2</sub>O to be split up into two hydrogen atoms and one oxygen, so I would assume a mistake is accpetable.
A man who does a mistake once is learning, if he does it twice he is a fool.
Now perhaps we can compare the energy given of when hydrogen combusts compared to the energy when MAPP or propane combust. I am not sure if it is that mach larger, most probably the higher combustion temperature of hydrogen is the reason for its "power", is this correct?
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Mon Jun 29, 2009 6:37 pm

john bunsenburner wrote:Alternatively it can be called browns gas, I am not sure why but its been used. HHO is incorrect as people said. The process is misleading though seeing as how one would expect H<sub>2</sub>O to be split up into two hydrogen atoms and one oxygen, so I would assume a mistake is accpetable.
A man who does a mistake once is learning, if he does it twice he is a fool.
Now perhaps we can compare the energy given of when hydrogen combusts compared to the energy when MAPP or propane combust. I am not sure if it is that mach larger, most probably the higher combustion temperature of hydrogen is the reason for its "power", is this correct?
Copied from another forum and authored by a fellow 'HHO' idiot.

"First of all, with a fast initiator (like a brisant explosive charge)
and atmospheric pressure (etc.), the gasoline will win, big time. Why?
At atmospheric pressures and temperatures, gasoline vapor is much more
dense than hydrogen. Even though hydrogen has much more energy per
pound, gasoline has much more energy per unit of volume.

Now, simply a spark to ignite the mix and the hydrogen will be MUCH more
brisant, it will deflagrate or detonate with a bigger "bang" because it
has a much higher propagation velocity than gasoline. In fact, hydrogen
burns so fast, it may not need an initiator to be an FAE. If you look
at the experimental data on flame front propagation, the measurements
showed supersonic propagation of the flame front in a tube, which would
turn it from simple burning or deflagration (combustion that propagates
through a gas or along the surface of an explosive at a rapid rate
driven by the transfer of heat wordnet.princeton.edu/perl/webwn
<http>)
to detonation (Detonation is a process of combustion in which a
supersonic shock wave is propagated through a fluid due to an energy
release in a reaction zone. It is the more powerful of the two general
classes of combustion, the other one being deflagration.
en.wikipedia.org/wiki/Detonation
<http>).

So, it depends, with a brisant detonator, the gasoline will still be
slower, but more powerful, with a flame as an initiator (no pressure
wave from the initiator), hydrogen will produce MUCH higher peak
pressures and a bigger "bang." Sorry, it is not simple.

Combustion is a complex subject (and I am not a guru in it), pressure,
temperature and density all matter. Hydrogen has a lot lower density
than gasoline (or gasoline vapor.) To cause ANY fuel/air mixture to
burn, the mixture must be raised above its autoignition temperature.
Hydrogen/oxygen mixtures are much less dense, they need less energy to
get hot enough to react. Gasoline vapor/air takes more energy to get
hot enough to initiate the reaction AND takes energy to complete the
reaction (which comes from the reaction and reduces the output energy.)
The time needed to transfer the energy slows the reaction.

Energy transfer rates are why hydrogen/oxygen reactions are much faster
than hydrogen/air reactions. Hydroxy is a hydrogen/oxygen mixture."

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Mon Jun 29, 2009 7:01 pm

im not quite sure what you are trying to prove with those videos? but there have been cannons made of this just not many. and i havnt seen any that are of considerable size.
http://www.spudfiles.com/forums/hydroge ... 16834.html
this was the first hydrogen gun i saw and it was the one that made me interested enough to tinker with the idea. but it was difficult for me to make an electrolyzer that could produce enough hydrogen for much fun so i just put it in a corner and eventually cannibalized it for other projects.
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