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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MrCrowley
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Tue Jan 27, 2009 6:59 pm
Oh are we all talking about combustions here...didn't see the topic section
*crawls back into hole*
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Combustion Monkey
- Specialist

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Tue Jan 27, 2009 7:04 pm
These are all outstanding ideas and the QCTBDC is absolutely brilliant! I should have stated in the beginning that this cannon is built around the idea of getting the most bang possible wile still being self contained and hand held, although heavy. So the idea of external air supplies are out. But this is still great food for thought for future cannon builds.So keep the ideas coming!
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Hubb
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Contact:
Tue Jan 27, 2009 7:08 pm
I think what Rag was referring to is that you should build yourself a quick change burst disk changer without the triggering of the burst disk.
In all honesty, that is probably going to be your best solution.
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Combustion Monkey
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Tue Jan 27, 2009 7:14 pm
As I stated above, I have built a quick disk changer of sorts. More of a cartridge. It even works with a golf ball loaded into it. Its a female to female coupler with one end taped up. The free end of the coupler gets slid onto the barrel stump. I just want something that is built into the gun and doesn't need to be replaced ,and I am sure that it can be done.
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jor2daje
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Tue Jan 27, 2009 7:17 pm
I doubt the flow would be any good in a large pop valve
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Combustion Monkey
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Tue Jan 27, 2009 7:21 pm
jor2daje wrote:I doubt the flow would be any good in a large pop valve
296 cubic feet per min. for the valve I am looking at.
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jor2daje
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Tue Jan 27, 2009 7:37 pm
Is it a straight line or does it flow through holes that most pop offs
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Ragnarok
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Tue Jan 27, 2009 7:52 pm
Combustion Monkey wrote:296 cubic feet per min. for the valve I am looking at.
That sounds very much like it's going to be on the low side. I can't tell you for certain without a pressure or temperature appended, or the specification of whether it's ACFM or SCFM...
For comparison, HEAL's valve pushes ~1600 SCFM at it's peak, and it's a much smaller cannon.
EDIT: My mistake, it's not 1200 SCFM, it's closer to 1600.
Does that thing kinda look like a big cat to you?
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Ragnarok
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Tue Jan 27, 2009 8:03 pm
Combustion Monkey wrote:How big is HEAL?
Not exactly very big. This picture should give you a good idea of the size (it's a a bit under a metre and a half)
I will admit HEAL does have a pretty powerful valve for it's size - however, big for it's size would be low for your size, so I reckon that you'd be better off with no valve at all than trying to add in a pop valve.
Does that thing kinda look like a big cat to you?
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Combustion Monkey
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Tue Jan 27, 2009 8:17 pm
Very nice gun. I half started this thread to see why no one was using some version of a mechanical dump valve. And now i have the answer I think. The answer is, why would you when burst disks work so well! I guess I'll just spend a little time refining my golf ball burst cartridges to see if I can maximize them. Thanks to everyone for the great discussion.