Why not to use acetylene as spud gun fuel.

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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joannaardway
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Thu Mar 15, 2007 4:45 am

Some people use actylene fine. Others won't - and it's the newbs/n00bs who come here, see your post and don't know how to construct correctly, and they'll blow themselves sky high.

And you couldn't hit even the merest fraction of the earth's escape velocity.

Now, go upgrade your n00bish posting skills, and post SAFELY!
Novacastrian: How about use whatever the heck you can get your hands on?
frankrede: Well then I guess it won't matter when you decide to drink bleach because your out of kool-aid.
...I'm sorry, but that made my year.
pyrodimitri
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Thu Mar 15, 2007 9:16 pm

I've made oxy/acetalyne guns before for the movie industry with great success. I whole project involves a lot of testing for no two guns use the same fuel ratio, even if they are built identically. You can shoot some types of ammo with good success as well, tennis balls and bowling balls work great. Again, I stress using caution when experimenting with this fuel mix and test, test ,test.
LGM
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Fri Mar 16, 2007 9:48 pm

I have heard that ABS, given the fact that it can withstand shock better than PVC, can be used with acetylene.
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Legendpilot
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Fri Mar 16, 2007 10:04 pm

joannaardway wrote:And you couldn't hit even the merest fraction of the earth's escape velocity.
Very true; intelligence is divine.
joannaardway wrote:Now, go upgrade your n00bish posting skills, and post SAFELY!
As well as humor. -Lp
Last edited by Legendpilot on Fri Mar 16, 2007 10:07 pm, edited 2 times in total.
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Extrusion
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Fri Mar 16, 2007 10:05 pm

LGM wrote:I have heard that ABS, given the fact that it can withstand shock better than PVC, can be used with acetylene.
It wouldn't be very smart to use it with either one.
"No living person is a virgin because life screws us all." - Extrusion
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Affliction
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Mon Mar 26, 2007 11:24 pm

I have used acetylene in the past in my gun.... Scary Powerful! just about knocked me on my ass from the recoil and the spud must have gone half a mile! My gun is a 4" by 2' chamber and a 2" by 4' barrel with a custom fuel/air automixer; no need to vent the chamber, does it at fuel load.
Blue flame everytime baby! I use sch40 ABS with no problems. Acetylene is way too unpredictable and explosive to use all the time so I went back to propane. I recently bought a canister of MPS gas which I'm gonna use as soon as I get my cannon out of storage; (don't ask, cops were at my house on a daily basis) Future mods are a breechload system with the spudcutter on the inside diameter to make a really tight round (you'd need a sledgehammer to load this way at the end of the barrel) The effect will be equivalent to a burst disc system but much more simple.
My cannon was capable of penetrating 1/2 inch plywood with a baking potato! Can't wait to see what MPS and mods do!
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c19o
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Mon Mar 26, 2007 11:35 pm

Affliction wrote: aNd the spud must have gone half a mile!!!
I think your gun would have blown up if the pressure was high enough to launch a spud that far.
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joannaardway
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Tue Mar 27, 2007 3:56 am

^Echoed. I've seen few reliable claims of ranges that high with a spud.

Spuds just aren't dense or aerodynamic enough to allow them to go that far except in very very rare cases.
Novacastrian: How about use whatever the heck you can get your hands on?
frankrede: Well then I guess it won't matter when you decide to drink bleach because your out of kool-aid.
...I'm sorry, but that made my year.
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Affliction
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Tue Mar 27, 2007 6:24 pm

c19o wrote: I think your gun would have blown up if the pressure was high enough to launch a spud that far.
well the field I tested my gun in at the farm is approximately 1/4 mile to the forest and I consistently put my projectiles into the trees at that range with propane. and I'm using 1/4 inch thick abs for the chamber which is 1/2 inch thick at the joiners where my fuel injection and ignition go through, so a very strong gun this is. And ABS does not make shrapnel like pvc; it just ruptures. So I figured I was safe to test acetylene. my cannon is 6' 6" in total length so this is not the pea shooter you guys are used to. I would not want to be near anyone trying this with pvc. The spud I used for this test was a large 6" by 2" monster which my dad grows on the farm. It quite easily cleared the trees and was still on an upward arc at that point. So I guessed it could have gone that far.
I was just stating I tried this as a fuel a few times and the ridiculous power it posesses but you take your life in your hands if you try it.
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schmanman
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Tue Mar 27, 2007 6:47 pm

Affliction wrote: and the spud must have gone half a mile!!!
umm, sure. whatever.

like joanna, I HIGHLY doubt this.

it takes a lot to propel a spud half a mile, not your everyday average spudgun. :wink:
8)
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sandman
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Tue Mar 27, 2007 6:52 pm

joannaardway wrote:
And you couldn't hit even the merest fraction of the earth's escape velocity.
lol, my uncle helped create a pipe used in a hydrogen fueled cannon to put something into orbit, it had like 40 injection points and 15 ignition points

anyway, if it was me id use only steel for starting tests with acetylene
maybe ABS if i thought it was safe but i doubt it
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Affliction
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Tue Mar 27, 2007 8:00 pm

You guys sound like a bunch of amateurs; a half mile is not that far....EX.
a 22 calibur rifle is lethal to a mile but that does not mean that the projectile cannot continue it's flight for two or three miles! it just means it has lost the inertia to be lethal. 1812 style cannons fired over 5 miles and they were very inefficient at sealing a projectile to a barrel. so is a half mile a strech for a 1 pound potato..... I don't think so. Fired at 45 degrees it is possible with enough power.
You spudders overcomplicate everything; the fuel meters and the multispark ignition and the like and you use "shrapnel producing pvc", no wonder you have no clue. You buy a propane brazing torch and elimate it's most important design feature; it mixes air with your fuel to produce the optimum.. IE. BLUE FLAME! and instead try and reinvent the wheel!
Figure out how to use the built in design features of the products you destroy/modify to do the job for you. If fuel and air are mixed as the enter the chamber they also expel spent gasses, DUH! my motto is the KISS theory (keep it simple smart guy). Fans in the chamber are MOOT.
The american military discovered they have more explosive destruction if they detonate above ground before impact instead of at ground level; basic psysics, so placing your ignition a few inches before the encap gives maximum effect. There are many disciplines of science involved in making an effective spudgun and first is understanding how fuel burns in a chamber and how to maximise it's output. Next is volumectric effieciency, how the expansion rate of combusting gasses will effect the effieciency of the barrel volume. I see all your video's on YouTube and all I hear are "FWUUMP" instead of a proper "PAKK" sound.
Pathetic!
I came to this forum to possibly learn something new I havn't tried and all I get from you children is "nope it's not possible and you are full of S$#T!" Sorry I did try acetylene and I posted my best guess as to the distance.
sjog
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Tue Mar 27, 2007 9:19 pm

No it is keep it simple STUPID
Killjoy
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Tue Mar 27, 2007 9:29 pm

not to criticize you or anything, but how old are you Afflication? And it might be in your best interests to post the cannon that did this (supposidly), along with specs, and possibly a video.
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Affliction
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Tue Mar 27, 2007 10:05 pm

Killjoy wrote:not to criticize you or anything, but how old are you Afflication? And it might be in your best interests to post the cannon that did this (supposidly), along with specs, and possibly a video.
I always love a Killjoy cause they break me out of my drunken stupor and focus my energy into killing this fucker! but ya I got specs and soon videos of massive destuctive power. I'm Early 30's with more knowledge than most of you 12 year old destructive punks. I'm interested in maximum performance out of a combustion gun. And acetylene just isn't the way. WTF! I did post specs! my bazooka is a 6'6" long by (4" by 2' chamber by 4' by 2" barrel) cut pipe lengths.... and All SCH40 ABS!
You are a pathetic imbecile if your spudgun goes "FWOOOMP" as you fire it.
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