Oxy Acetylene as a fuel

[Jolly Roger]

lol

[VEGEMITEMODDER]

one or the other

[dinsdale]

first of all i suggest you forget this idea, waaay too much potential.
however i built a super simple oxy acetylene cannon and it worked.
i am a welder and i made it at work to prove a point, i used a 4 foot piece of 2" ID sch 40 galvanised steel pipe with a 1/2" plate welded to the end with a 9/16" hole in the center. i crammed a potato down the barrel leaving about 6 inches for gas, i filled it by obtaining a neutral flame on the torch, and then blowing it out and putting the nozzle into the hole in the steel plate. when i figured i had enough gas (after about 1 sec.) i pulled the torch out and quickly
covered the hole with masking tape. i then lit the torch and touched the flame to the tape patch. it was extremely loud, had insane recoil and fired the potato
so hard that it dented the door of a boxcar.

PLEASE - DO NOT ATTEMPT USING OXYGEN IN ANNY CANNON!!!!

IT WAS EXREMELY STUPID ON MY BEHALF DESPITE THE SUCCESS

[spudmonkey]

so i use oxy-mapp all the time, untill now because i ran out of oxy its really fun loud and it kicks farily well

[Jolly Roger]

Hey spud with oxygen, do you have to go and but a new canister every time you run out or are you able to get it filled some how. I get my mapp gas bottles refilled at work, saves a bit of cash, but I wasn't sure bout oxygen thats all.

[spudmonkey]

i dont know of anywhere i can get it filled although i would like to find a place that would or buy a larger bottel thoes bernz-o-matic oxy bottels dont have much in them, i only use it with oxy in my sch80 over-under, it lasted me 25 shots but i also cut a fence down with it so i dont know how many shots you would normaly get out of it, i didnt know that their was places to get mapp gas filled

[schmanman]

maby a medical supply store ?

[spudmonkey]

actually thats an idea my brother is a firefighter-ems i bet hes got acess to that sorta stuff

[schmanman]

having connections is nice, eh ?

[SpudStuff]

The red cans next to the propane at the hardware stores are oxygen.
This guy used it in abs without problems.Retarded Cow Shit

[spudmonkey]

yah its good, when your hangin out with him and he gets a call now that fun, get to see some cool stuff
spudstuff: that was what we were talkin about

[whatthehellamidoing]

over the summer i had a job as a welder/steel fabricator. one of the guys i worked with had an oxy-acetylene cannon, and we could launch a 4 inch solid steel ball about 400 feet. before you make one of these, make sure you use 1/4 in steel pipe, with an endcap with a very strong weld. otherwise, the pressure created by an explosion of that size will burst pvc. even with the 1/4 in steel, it is still very dangerous as acetylene is an extremely active gas, and has to be stored with acetone so it doesnt combust. acetlyene will automatically combust at 15 psi, and that is enough to tear the cannon to shreds. be very careful if you attempt this. i can try to put some plans up for you of our cannon, but i do not recommend shooting this cannon very often.

[dinsdale]

Another warning about acetylene,
it reacts with copper forming acetylide (i'm pretty sure thats the name)
it is a very poisonous gas, and can be lethal.

[boilingleadbath]

Ok, I'm going to go and apply standard chem-1 gas laws and figure out the silly pressure in the chamber of an O2-C2H2 combustion...

flame temp: 3700 K
Stanting temp: 300 K

2C2H2 + 5O2 -> 4CO2 + 2H2O
(7 moles reacts to form 6 moles)

Assuming pressure starts at 1 atmophere...
1 atm * 3700K/300K * 6mol/7mol = 10.6 atm

(if you are wondering... "which f'ing gas law is that?!" - it's not. It's boilingleadbath's law, peiced together on the spot from an inate understanding of the subject matter. Why go to the hassle of using the ideal gas law in this situation?)

10.6 atm (sorry about sig. figs...) is equal to 155 psia (10.6 * 14.7).
We typicaly use psig in our conversations, so that's 140 psi; about the (calculated) pressure generated by a 1.5x hybrid.
(for comparison, a I've calculated a propane-air combustion to produce something like 86 psi)

So, there is some benifit to an oxygen-acetylene cannon. (there is not much, if any, pressure benefit to a acetylene-air cannon; all benifits there are due to a increased burn velocity.)

...is it worth the noise, saftey hazard, and handling charistics of the fuel and oxidizer?
Honestly, I don't think so (and would opt to simply add a burst disk or use a hybrid), but others may think differently.

...oh, and cupric acetylide is a solid explosive. (I don't know if it's very poisonous, but I don't think you should go eating sensitive HEs)

[reaper613]

hey i only use oxy acetylene, my gun is sch 40 steel pipe and it handles the pressure fine.