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Post questions and info about combustion (flammable vapor) powered cannons here. This includes discussion about fuels, ratios, ignition systems, safety, and anything else relevant.
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Unread postAuthor: marpat » Sun Sep 07, 2008 2:23 pm

heres whats running through my head

1. dont use hydrogen peroxide in a spudgun

2. i thought your parents wouldnt even let you build a spudgun to begin with

3. have you even built a basic spudgun?
if so i would love to see pictures

4 how about you just build more basic spudguns and get experience before you attempt this
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Unread postAuthor: jimmy101 » Sun Sep 07, 2008 3:05 pm

Besides the problems (read HAZARDS) associated with the use of hydrogen peroxide you will have to figure out a way to actually make it work in a spudgun.

How will it be metered? How will it be ignited?

Even if you could get 60% peroxide it's still a liquid at NTP. Shake it up with a reducing agent (fuel) and it may well autoignite. That is not good since it is uncontrollable. If it doesn't, how will you fire the gun with a bunch of water sloshing around in the chamber?

When peroxide is used as a rocket fuel it is metered and pumped at high pressure into a combustion chamber. The fuel is also metered and pumped into the chamber. The system is setup to either autoignite or a spark is used to intially fire the mixture. Really don't see a way to do this in a spudgun.

Like everybody else has said. Start with a standard combustion (that'll give a gun with about the same KE as a low power rifle). Work up to either a hybrid or a pneumatic. H<sub>2</sub>O<sub>2</sub> is impractical. There are many other ways to get to that kind of chamber energies without the serious complications involved with H<sub>2</sub>O<sub>2</sub>.
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Unread postAuthor: psycix » Sun Sep 07, 2008 4:16 pm

Besides all the dangers and every other statement made about H2O2 in this thread, please note that it is also a very unpractical way of fueling:
1- It may be a very expensive fuel per shot. You may put alot of money into this project and only fire it a few times.
2- You may need to distill it and have alot of hassle before you can use it. Hours of work, seconds of fun.

Is an hybrid not good enough for you? If you want a very powerful gun, just construct a very high mix hybrid. Easier, cheaper, safer and much more fun.

HOLY crap just before hitting the Submit post button my little brother come into the room and opened up a drawer. Its a drawer where I keep my chemicals in like KNO3, S, NaOH, distilled water, a can of butane and some other stuff. A bottle of 30% H2O2 was also there.
Now the following happened:

We discovered a leaking bottle of H2O2 and a hole was eaten through the bottom of the drawer!
The bottle is somewhat pumped up and droplets were all over it.
The bottom of the drawer is soft, and the bottle dropped down into the drawer below.

OMG this unlucky coincidence. I was just posting about H2O2 and during that, I discover this....

First I am going to clean up some stuff over here, pictures come tomorrow.
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Till the day I'm dieing, I'll keep them spuddies flying, 'cause I can!

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Unread postAuthor: ramses » Mon Sep 08, 2008 3:29 pm

@magnum- sorry the user on 4hv's user name was thermite. you both shared less than safe ideas (mixing chlorate's with thermite). My bad.
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Unread postAuthor: Necrosis » Thu Sep 11, 2008 4:17 am

Isn't hydrogen peroxide used to bleach your hair and stuff?
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Allthough we may be the most intelligent creature on this planet, we are also the most inconsistent.
To find peace within our existence we often create a logic that endangers our lives.
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