1000psi+ semi auto marble gun

maggotman · Sat Jan 31, 2009 8:03 pm

i have got some electrical conduit thats a perfect id for marbles and a real tight fit in 22mm copper. pipe basically im looking for some sort of breech loading that will reload itself. i am going along the lines of a piston valve held closed by a spring and a form of valve to limit air going to the chamber to stop the valve honking i will be storing the air in 1 or 2 fire extinguisher's an be using it at full pressure.

sputnick · Sat Jan 31, 2009 8:06 pm

good for you?

maggotman · Sat Jan 31, 2009 8:10 pm

real constructive post eh ?

if i have the balls just drop into the pipe will they self feed or will i need a spring

sputnick · Sat Jan 31, 2009 8:12 pm

Oh you actually had a question, I thought you were just bragging about your gun before it was even built...

I have no idea what you are saying, you need a diagram, mate.

maggotman · Sat Jan 31, 2009 8:18 pm

i would love to draw one but i don't have any drawing programs on my computer
would you no of any free online drawing facility's

sputnick · Sat Jan 31, 2009 8:20 pm

um, paint? every windows computer has it...
if you are not running windows or for whatever reason lost it, dowload paint.net, its not a website, the program is called paint.net, you can get it at download.com

maggotman · Sat Jan 31, 2009 8:22 pm

thanks im running windows basically i got a virus and deleted some important things by accident trying to fix it

snobum101 · Sat Jan 31, 2009 10:14 pm

go gravity feed bro

sputnick · Sat Jan 31, 2009 10:18 pm

Snobum, just no.

really, just no.

Magasines that go above the barrel look shitty.

That sh|t may have flown in the 1920's but come on, so many people just skip on a spring and a chance to make awesome guns.

Ragnarok · Sat Jan 31, 2009 11:02 pm

Have you actually bothered to look up what the working pressure on 22mm copper actually is?

It's ~750 psi, which falls somewhat short of your optimistic 1000+ psi planned pressure, and even with your conduit added, I wouldn't be doing this, because, bear in mind, the working pressures on British copper pipe are usually not far off the pipe yield pressures (although they fall at around a quarter of pipe burst pressures), so it is ill advised to take them past their working pressures - and I wouldn't advise exceeding more than perhaps 500 psi in even the smaller bores of UK copper (especially not the larger ones) - and even then, that would be only if you had extensive experience using and building cannons of higher pressures.

Now, I'm all for taking things further, but do you not think this might be too far?

inonickname · Sun Feb 01, 2009 12:30 am

Ragnarok wrote:Have you actually bothered to look up what the working pressure on 22mm copper actually is?

It's ~750 psi, which falls somewhat short of your optimistic 1000+ psi planned pressure, and even with your conduit added, I wouldn't be doing this, because, bear in mind, the working pressures on British copper pipe are usually not far off the pipe yield pressures (although they fall at around a quarter of pipe burst pressures), so it is ill advised to take them past their working pressures - and I wouldn't advise exceeding more than perhaps 500 psi in even the smaller bores of UK copper (especially not the larger ones) - and even then, that would be only if you had extensive experience using and building cannons of higher pressures.

Now, I'm all for taking things further, but do you not think this might be too far?

Maggotman doesn't seem to have problems doing incredibly unitelligent things, and push things a lot further than they need to be. Like modding fidge compressors, also see my sig.

While it's usually safe, I wouldn't mess around with pressures like that in copper.

Hotwired · Sun Feb 01, 2009 7:26 pm

sputnick wrote:Magasines that go above the barrel look shitty.

I don't know, I kinda like the Bren gun.

Admittedly having a magazine on top does seem to bother some people although it makes no difference at all to the cannon and considering the accuracy to start with, not losing much in that department either.

I have a number of sketches which simply flip the cannon over...

The magazine is now conventionally underneath and you get the chamber at the top to mount stuff on.

maggotman · Sun Feb 01, 2009 7:44 pm

I think you will find that i am well with in my limits working with copper. pipe
http://www.airlink-compressors.co.uk/Tu ... r_tube.htm
near the bottom copper pluming pipe.

I am not going to disagree what I am doing is not the cleverest of things but if i thought i was going to get blasted with bits of shrapnel under very high pressures i would not be doing it.

In one of my guns using 15mm pipe as a barrel it has bulged out from firing but im not allowed to discuss cannon in the forum because of the rules.

tried out my barrel today at 600psi impressive results got a marble threw 18mm plywood with ease i shot one at a 3x7 and it was imbeded about 1 inch deep, i was using a 150mm barrel with a 20cm 22mm copper pipe as the chamber, even tho i am using a small chamber it is still quite loud.

Could i put the pilot under the marbles to push them up into the barrel and
were would i get such a spring with enough force to lift 10 or so marbles also what about if a had the mag in line with the barrel then with a 90 bend into the breech.

Hotwired · Sun Feb 01, 2009 7:55 pm

a) The pilot gas is still compressed gas, it is possible you could make an arrangement to force the marbles along.

b) Have a look in DIY shops, any random hardware places for springs or even online merchants. Off the top of my head I know Maplin and MUTR stock various springs.

c) That can work too.

Also, I really hope that's a typo for the cost of that sites copper plumbing pipe.

Sticky_Tape · Sun Feb 01, 2009 8:39 pm

Somthing unrelated but not worthy of a separate topic: http://www.airlink-compressors.co.uk/Fi ... st%20valve Take a look at the qev's for low price.
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