Hydrogen

Harness the power of precision mixtures of pressurized flammable vapor. Safety first! These are advanced potato guns - not for the beginner.
LGM
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Sat Feb 17, 2007 9:24 pm

Would a 2x shot with hydrogen shatter sch 40 2" steel pipe?
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Sat Feb 17, 2007 11:23 pm

In simple terms, no, but I REALLY wouldn't advise it. There's too many safety hazards.
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frankrede
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Sun Feb 18, 2007 12:38 am

I really don't know but I would feel more comfortable with sch 80 higher
Current project: Afghanistan deployment
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BC Pneumatics
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Sun Feb 18, 2007 10:13 am

In my opinion, it is very possible that your chamber would fragment, especially if it was long. (flamefront acceleration is not always your friend.)

Also, what is meant by 'a 2x mix' ?
This tells us absolutely nothing. In hybrid terminology, it refers to the number of atmospheres of pressure inside the chamber. If you really meant "a stoichiometric mix of H2 & O2 pressurized to 2atm" then you are sure to run into some serious trouble.
Last edited by BC Pneumatics on Sun Feb 18, 2007 10:28 am, edited 1 time in total.
LGM
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Sun Feb 18, 2007 10:39 am

I mean a 14.7 psi mix of hydrogen at aproximatelly its ideal percentage in air.

I would only use pure H2 O2 in a very small, very thick pipe.
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Velocity
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Sun Feb 18, 2007 10:42 am

Doesn't hydrogen corrode some type of metal pipe, maybe steel or aluminum?
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BC Pneumatics
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Sun Feb 18, 2007 10:43 am

LGM wrote:I mean a 14.7 psi mix of hydrogen at aproximatelly its ideal percentage in air.

I would only use pure H2 O2 in a very small, very thick pipe.
This doesn't make sense...
You also might want to note that a stoichiometric mix of H2 and O2 can reach a peak velocity of 4,000 meters/second right after DDT occurs. (The main point is- will you have a large enough chamber for that to happen.)
LGM
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Sun Feb 18, 2007 10:46 am

You are refering to embrittlement. In high pressure applications, hydrogen will react with the carbon in carbon steel pipe to create methane, weakening the pipe. I am not worried about this happening. I would have it at low pressure for short periods of time. And if I did fire it with hydrogen, I would only do it a couple times in case of pipe weakening from the shock.
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BC Pneumatics
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Sun Feb 18, 2007 10:54 am

Two inches isn't a 'very small pipe'
LGM
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Sun Feb 18, 2007 11:01 am

I know, I will not be adding oxy to this, just air. I said if I would, then I would use very small pipe.
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BC Pneumatics
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Sun Feb 18, 2007 12:46 pm

It would have been nice to include everything you planed to do, in your first post. You don't want a '2x mix of H2 and O2", 2x mix of H2, O2, CO2, CO, N2, and a host of other things in there.

I still don't know how far I would trust a 'steel chamber' though. It would actually depend a lot on the ammo.
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Thu May 17, 2007 8:37 pm

LGM wrote:Would a 2x shot with hydrogen shatter sch 40 2" steel pipe?
If you are still watching this topic - I am interested in how you would obtain, then carry / meter / deliver the hydrogen.
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BC Pneumatics
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Fri May 18, 2007 8:16 am

While this should really be a separate topic, using a water small pump to displace hydrogen from a bottle is a simple and effective method that I like to use.
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Fri May 18, 2007 9:45 am

BC Pneumatics wrote:While this should really be a separate topic, using a water small pump to displace hydrogen from a bottle is a simple and effective method that I like to use.
I was thinking in terms of a pressurized mass supply rather than small amounts made by electrolysis in a two-litre bottle. Though if you could make large amounts on-site at the firing range . . . Would take a lot of power.
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dongfang
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Fri May 18, 2007 10:57 am

Hi,

Anyway why would anyone want to use hydrogen?

I did the figures once; it is not a very good potato gun fuel. Reason: Extremely high energy density per mass unit, but also extremely few mass units per volume unit. Result: Only moderate size o' bang in a chamber. Smaller than for many other fuels.

Soren
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