combustion Marble cannons ?

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.
Walsh_3rdE
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Wed Apr 04, 2007 2:57 am

( sorry if this is the wrong section to ask for help)


Im wanting to make a a combustion marble cannon but all my experience is in making farly MAssive potato chuking ones.

Is it possable to have a big enough chamber to make it fire a long way ( eg 200 meters umm or americans i think thats around a bit under a 1/4 mile ) and not get my hands blown off when it fails to escape quikly enough through the marble sized barrel pipe


Cheers :twisted:

other ammo would incluse AA batties
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jackssmirkingrevenge
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Wed Apr 04, 2007 3:13 am

Walsh_3rdE wrote:Is it possable to have a big enough chamber to make it fire a long way ( eg 200 meters umm or americans i think thats around a bit under a 1/4 mile ) and not get my hands blown off when it fails to escape quikly enough through the marble sized barrel pipe
If you're using pressure rated PVC, not much chance of a failure happening. get yourself some 3/4" i/d PVC for a barrel as long as you can afford to make it and have a chamber of the correct ratio to match.
hectmarr wrote:You have to make many weapons, because this field is long and short life
Walsh_3rdE
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Wed Apr 04, 2007 3:25 am

thanx Jackss

my previous cannons have a C:B ration of 1:1.5 the barrel not heaps bigger than the chamber - will this do ? what C:B ratio would you recomend
Walsh_3rdE
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Wed Apr 04, 2007 3:29 am

you may laugh at this but ive only been mesuring the C:B ration by length of pipe even though the Camber is double the size width ways. so in effect if i was to messure volume of the inside it would prolly end up 1:1.1 - 1.2 :P

am i correct in measuring the chamber by length only or should i be calcualting the volume to come up with my C:B ratio's ???


thanx again
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Redcoat
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Wed Apr 04, 2007 3:30 am

well what i would do for that is use my normal potato gun chamber and change the reducer on it to one that brings it down to a medium sized marble calibre.
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Walsh_3rdE
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Wed Apr 04, 2007 4:03 am

- not a bad idea - exept my normal chamber size is 100 mm reducing that to the size of a marble would be difficult because i dont think reducers step down that far from that size.
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Redcoat
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Wed Apr 04, 2007 5:28 am

well you could fill the gaps with some sort of silicon or hot glue gun style stuff.And you couls always use the large marbles, Tombowlers (thats what there called in my commnity and its the worst name but wth.) :D
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Walsh_3rdE
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Wed Apr 04, 2007 5:38 am

could work execpt i would have to use an end can and drill a hole in it and silcon around that. would work but would also be weaker -

thats probly not to bad idead if 1 i use two caps back to back so there is extra support and 2 its a good fail safe - istead of it blowing up the barrel shoot into the distance :P
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Wed Apr 04, 2007 7:04 am

i hope i helped. :fart:
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locksmith
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Wed Apr 04, 2007 11:20 am

just out of curiousity why go combution for a marble gun and not pnuematic?
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Wed Apr 04, 2007 12:00 pm

well, for the chamber, use 30 cm of 8cm wide pressure rated pipe, and for the barrel, 1 meter of 3/4" PVC pipe. And, no, 200 megters is more 1/8 of a mile.
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Walsh_3rdE
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Thu Apr 05, 2007 1:22 am

Locksmith asked why go combustion

basically coz ive never made a pnuematic and

1 i wouldent know how to make it air tight and get all the plugs that fit the pum/compressor

2 i dont no how to hook up the valve proply


3 a pnuematic your right would probly be better however a combustion is easyer , quicker and prolly less expensive to build
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