SpudFiles

Hello, I have recently been making designs for a pump action combustion, and plan for it to have both oxygen and propane injected into the chamber whenever the handle is pumped, negating the need to vent after shots. However, I need a cheap, pressurised source of oxygen that I can mount on my cannon. Any help would be appreciated.

However, I need a cheap, pressurised source of oxygen that I can mount on my cannon.

Not a phrase that really works together.

You can buy small disposable cylinders (which run out rather quickly), or larger cylinders which can be quite expensive and hard to lug around. If you're willing to homebrew, you could use electrolysis or decomposition of chlorates and pressurize it yourself.

I'd avoid homebrewing the stuff, as you run into massive dangers. Do you know the problems with working with oxygen?

I'm not sure if he does, but i don't. Please go on

http://www.hse.gov.uk/pubns/hse8.pdf

As an example, smokers in oxygen tents have set fire to themselves, their bed, the tent and then the hospital. By just lighting a cigarette.

Woah yeh i see *OUCH*

Like inonickname said. Probably the most readily available are Bernzomatic torch Oxygen cyclinders. You'll need the correct fitting since it is non-standard (and left hand thread).

Figure you need 20% of the chambers volume for each shot. So 20ci for a 100ci chamber (that's a pretty big chamber for what you are trying to do).

Looks like the standard cylinder contains about 40g of Oxygen ... 1.25 mole ... 28 liters at STP ... 1700 ci at STP. So ball park puts it at 85 shots for the 100 ci chamber. Not to bad. I think the cylinder is about $9, about ten cents per shot for the O2 for a largish chamber.

You might just get the Bernzomatic oxygen tourch setup:
http://hand-tools.hardwarestore.com/69- ... 04797.aspx
If you do it right you could use the MAPP and O2 and still be able to take it back off the gun and use it as a torch.


EDIT: There are some pretty significant safety issues with using pure O2 into a closed chamber. If you ever get both the fuel and O2 cylinders connected at the same time you run the risk of a huge explosion. Not like a typical combustion or pneumatic chamber failure, more along the lines of the garage (and you) are gone.

I did it and it worked for a while, then everything inside the chamber melted and caught on fire. If you add too much oxygen, there can be left over which enables stuff inside to burn, so use a spark plug and a metal chamber. It does run out fast as hell, at least the way I was using it. I officially ditched the idea altogether and think I will go with HPA for a cannon like mine at some point in the future, or if I decide to make another one like it. The O2 is picky, expensive and can be dangerous.

Hmm ok then, would those camping stove fuel things which have both fuel and air in them work?

EvilFish wrote:Hmm ok then, would those camping stove fuel things which have both fuel and air in them work?

Camping stove fuel things don't have both fuel and air in them, if you're reffering to the things I think you are. Pressurized gas mixtures almost NEVER contain both a fuel and an oxidizer, for safety reasons. One source of ignition, and BOOM!

I'm certain I read about them on spudfiles, someone was using them to fuel their mini because he could just flood the chamber with it.

Ok, I have been looking around, and have decided to use a large venting valve that opens with the action of being pumped, and a fan to help with fast venting. This is a similar to the system on the TITS I believe. thanks to everyone for thier help.

EvilFish wrote:I'm certain I read about them on spudfiles, someone was using them to fuel their mini because he could just flood the chamber with it.

They were using an air mixer, basically just the standard Bernzomatic propane torch head (or a Bunsen burner). As the propane flows throught the head it sucks air in at more or less the correct ratio. Flush a chamber with enough of that and you purge the spent gases from the previous shot and provide fuel + oxygen for the next shot. Figure you need at least a couple chamber volumes worth of fuel+air mix to get reasonably close to the proper mixture.

A moveable piston that pushes the spent gases out of the chamber followed by a powered return while the torch head supplies fuel might work.

jimmy101 wrote:There are some pretty significant safety issues with using pure O2 into a closed chamber. If you ever get both the fuel and O2 cylinders connected at the same time you run the risk of a huge explosion. Not like a typical combustion or pneumatic chamber failure, more along the lines of the garage (and you) are gone.

Do I hear detonation versus rapid deflagration?

EvilFish wrote:Hello, I have recently been making designs for a pump action combustion, and plan for it to have both oxygen and propane injected into the chamber whenever the handle is pumped, negating the need to vent after shots. However, I need a cheap, pressurised source of oxygen that I can mount on my cannon. Any help would be appreciated.

I'M NOT SURE IF THIS IS A COMBUSTION QUESTION I'M KINDA NEW BUT IT SOUNDS LIKE A HYBRID QUESTION USING COMPRESSED AIR AND FUEL.