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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super spuder
- Corporal
- Posts: 558
- Joined: Fri Apr 06, 2007 9:05 pm
- Location: Ontario Canada
Wed May 16, 2007 3:58 pm
Some of you may remember my last topic on this. I am actually going to build it now that is is nice out. I went and got this
as the chamber, it weighs 20 pounds
so this cannon is not going to be portable. I might also run accetaline and oxygen in it
. As for the barrel, it is probbly going to be 1 and 1/2 inch so i can shoot golf balls. i am going to use a coil and spark plug to ignight it. So just tell me if you have any comments sugestions or if you want to call me stupid, go for it. I just have one question. How thick should the barrel be?
trying to decide on a new project, probably something small.
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frocksie
- Private 4
- Posts: 91
- Joined: Fri Mar 23, 2007 2:05 pm
- Location: Maine
Wed May 16, 2007 4:08 pm
What is the volume of that chamber?
“He who controls the present, controls the past. He who controls the past, controls the future.”
-George Orwell
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spudthug
- Corporal 5
- Posts: 936
- Joined: Mon Feb 26, 2007 9:02 pm
- Location: johnsonburg, Pa USA
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Contact:
Wed May 16, 2007 4:26 pm
what the hell was that thing??!?!? sure do it but it may be hard getting the rusted parts off.. put a union on it for a burst disk..to make it loud..of course..obviously...dur..ill stop now....
4" piston valved cannon-half done..( i spilt my cement...)
Hybrid- 75% done. need to build propane holder and drill/tap sparkplug hole..
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SpudMonster
- Specialist 2
- Posts: 250
- Joined: Mon Aug 08, 2005 5:54 pm
Wed May 16, 2007 4:44 pm
Okay, first, a 1 1/2" barrel will not fit golfballs. It has to be a 1 1/2" SDR 21 barrel sleeved within 2" SCH 80 pipe.
Second, that bears a remarkable resemblance to the air chamber for an old piston-driven water pump such as <a href="
http://www.steamengine.com.au/events/re ... .jpg">THIS ONE</a>
While they are heavy, that is due to their cast iron construction. It's heavy, but casting techniques of yore left something to be desired at times. Not only that, but cast iron does not like high tensile loads very much, or shock loads. Both of whis it would see this application.
Want my advice? Don't use that as the chamber.
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super spuder
- Corporal
- Posts: 558
- Joined: Fri Apr 06, 2007 9:05 pm
- Location: Ontario Canada
Wed May 16, 2007 5:16 pm
@spudthug that was a pressure tank for a water pump. and heat from a torch will get anything off
i will go and find the volume
@SpudMonster this chamber was built to handle high water pressure, so it should not have trouble holding gass pressure
trying to decide on a new project, probably something small.
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sandman
- Corporal 2
- Posts: 672
- Joined: Thu Mar 15, 2007 6:59 pm
Wed May 16, 2007 6:13 pm
wouldnt heat make it worse?
would that not increase the reaction rate of iron and oxygen?
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super spuder
- Corporal
- Posts: 558
- Joined: Fri Apr 06, 2007 9:05 pm
- Location: Ontario Canada
Wed May 16, 2007 6:18 pm
it is not made of iron, and the volume is about 175 cubic inches.
trying to decide on a new project, probably something small.
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frocksie
- Private 4
- Posts: 91
- Joined: Fri Mar 23, 2007 2:05 pm
- Location: Maine
Wed May 16, 2007 6:25 pm
Is it 14in x 4in approximately?
“He who controls the present, controls the past. He who controls the past, controls the future.”
-George Orwell
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super spuder
- Corporal
- Posts: 558
- Joined: Fri Apr 06, 2007 9:05 pm
- Location: Ontario Canada
Wed May 16, 2007 6:33 pm
it is 10 by 4.5 plus the extra bit which is 2 by 2 aproxamatly. It is hard to tell because the bottom is bowl shaped and i don't know how thick it is yet
trying to decide on a new project, probably something small.
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cb4289
- Specialist
- Posts: 123
- Joined: Fri May 04, 2007 1:24 pm
Wed May 16, 2007 6:59 pm
That thing looks like it coluld kill you when you shoot it off. er. well maby not depends on what fuel you use and how thick it is.
dose my big ass make my ass look big -rosane
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frankrede
- Sergeant Major 2
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Wed May 16, 2007 10:08 pm
I wouldn't trust it with oxygen.
Maybe a plain old wimpy propane shot.
But even then I would hate to see you mess with oxygen/
Current project: Afghanistan deployment
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noname
- First Sergeant 4
- Posts: 2698
- Joined: Mon Apr 10, 2006 9:19 pm
- Location: Bay Area, CA
Wed May 16, 2007 10:46 pm
I have managed not to kill myself yet, shooting my soda can gun with propane and oxygen. I'd say you're safe if you remote fire (at least 50 feet away) and you're behind something stronger than 1" plywood.
Last edited by
noname on Wed May 16, 2007 11:07 pm, edited 1 time in total.
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FeLeX
- Specialist 3
- Posts: 310
- Joined: Sat Mar 10, 2007 10:45 pm
Thu May 17, 2007 1:16 pm
Why are people always sh!tting their pants when they hear that some one is going to use oxygen? What if they have a very sturdy tank? I mean what kind of pressure does oxygen make that makes you all so scared of it?
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Pete Zaria
- Corporal 5
- Posts: 954
- Joined: Fri Mar 31, 2006 6:04 pm
- Location: Near Seattle, WA
Thu May 17, 2007 1:27 pm
Sorry super spuder, but I think SpudMonster is dead on right; that's a cast iron cylinder probably from a water pump or steam apparatus.
In either case, it's not made to handle extreme pressures, but even moreso, it's not made to handle extreme pressure spikes.
Especially covered in however-many-years-worth of rust.
Sorry to say it, but I'd look for a stronger chamber. Look for a scuba tank or other gas tank that's too old to be officially used anymore, or something like that. We'd hate to see something in the news about "Local teen killed by shrapnel from home-made oxygen-burning potato gun"...
If you do choose to use this thing, test fire it 50 times remotely and then THROUGHLY inspect it for signs of wear.
Peace,
Pete Zaria.
