Combustion Or Pneumatic?

[julz]

Hi, I am about to start making a normal sized spud cannon with my Dad. i have some inner conflicts about what type to make. Below I have written the pro's and con's that I know of for each gun. Could you post you opinion on what I should make as well as any other factors. Thanks!

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               Combustion
       Pros
easy to make
cheap
many shots in little time
fire good distance   
portable




cons
Very Loud
 explosions=fire=possible bushfire
 illegal
require flammable fuel to work



                        Pneumatic
       Pros
shoot farther than combustion
quiet
does not require fuel=no fire danger        
basic design
possible loophole in law to get out of trouble




Cons
must pump for every shot=low rate of fire
not portable
big

thanks for any help, --->Julz

[iamthewalrus]

shouldnt low rate of fire be a con, and i love the pnumatic loophole

[julz]

it is. that is where it goes on my screen anyway. jst checked and this is a resolution issue. i'll edit it to work now.

[PCGUY]

You can add a pro to combustion with the ability to be portable, with a pneumatic it's much harder to do.

Pneumatics are great for somewhere where you will be for a whial, but if you want to take your spudgun over to some campout for the night, a combustion with onboard propane would be your best bet.

[v3ngence]

Arn't we all forgetting about the kool factor when you shoot a combustion in the dark? Thats actualy the main reason I decided to try combustions, you just can't beat the muzzle fire...

[julz]

well ATM i'm leaning toward a Combustion with a silencer and onboard propane. can somebody plz explain how the onboard propane system works with a metering system, like on http://www.spudtech.com. thanks


UPDATE: turns out that pneumatic's are also illegal after closer inspection of the NSW Prohibited Weapons list.

Item 2(3) Any device that is designed to propel or launch a bomb, grenade, rocket or missile by any means other than by
means of an explosive, including a device known as a PVC cannon.

this means basically if it doesn't use an explosive it it still illegal if its designed to blah blah blah. is a potato a grenade, bomb, rocket or missile? i dont know. what do u reckon? legal or not?

[PCGUY]

I would say you will be fine as long as you are out shooting somewhere where there isn't anyone around. I don't think a spud is a gernade, bomb, rocket, or missile.

[CS]

If said this before combustions are way cooler. The only thing pneumatics have on combustions is they shot farther. Pnueumatics might be better for old people because there not going to moving a whole lot with there gun. I like combustions because i can put it in my guiatar back pack and ride to my freinds house on my bike. Another reason why combustions are better is do you want a loud BOOM and a flame or do you want a whoosh of air. Me i like loud noise and a boom but maybe your different. Build a Combustion!

[julz]

well, my dad has decided to make a pneumatic cos hedoesn't think the way we all do. ie. gas+spark+dead grass and dry trees=FUN
i'll edit when we have decided what type to clone.

alright, we're going to make a Peacemaker clone with a ball valve rather than use electronic stuff. it will be a simple 'U' shape with a wooden stock. i'm going to post 3d pics soon of what it should look like.

one other question. with the compression chamber how do you pump the air in? do i need a special valve or what? thanks

jpeg

rar file of 3d animated gif(4megs)
the pics are not fully detailed and don't have all the features, just the basic shape

[julz]

any ideas people?
any answers?

[iamthewalrus]

y donht u use a sprinkler valve mod instade of a ball valve, ball valves suck, sprinkler valves are a lot better, and moded ones dont even use electrics

[julz]

i don't get how sprinkler valves work, i have to go now but would you please explain hot to implement them?
that would be very much appreciated.
bye!

[iamthewalrus]

just go to the how to, its all there, itts a lot easier then it looks, take out the scrws, take off the top, tap in a hose and blowgun and appoxy the solinoid hole. thats about it in a nutshell

[julz]

ill try this. only problem is i dont know i u can get tham where i am. i guess i could try and fall back on a ball valve if i stuff up.

plans for cannon coming soon!

EDIT: here is a shitty pic

the chamber is made of 2.5" by 10" PVC with an endcap on it. then it goes to a 2.5" to 1.5" reducer. this leads on to a 1.5" coupling and 90 mm of 1.5" PVC pipe.then it has a 90 degree turn, 60mm of 1.5" pipe and aother 90 degree turn, making the 'U' shape. 60mm of 1.5" PVC comes next followed by either a sprinkler or a ball valve, then 50mm of PVC pipe, a 1.5" coupler, a 1.5" to 1" reducer and a 1" by 36" PVC pipe.

[Harpoon]

Ball valves can take higher pressures and are better if you want to shoot stuff at 200+ psi
They work fine and can be made to open faster by using a spring to open them.

Obviously you'll be using copper pipe or something stronger at these pressures