construction materials
Not that anyone asked,but in my humble opinion the best expansion chamber is made from a large,(say 20 lb) fire extinguisher tank.The best barrel is made from a piece of 1" copper pipe about 4' long.The best propellant is oxygen and butane,and the best projectile is the bottom end of a ski pole wrapped with cord and topped with shrink tube.You won't blow it up,the smaller barrel concentrates more force,the propellant burns completely and the projectile will penetrate just about anything.Even rock.I've fired through both car doors and into a 55 gallon drum on half a balloonful of oxygen and two tiny shots of butane.C batteries work pretty good,too.Or you can use a 11/4" barrel and use those cheap,driving range golf balls -with the shell taken off- as projectilesThey will bounce back after going through a cinderblock and two bricks,though,so shoot from behind protective cover.
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brogdenlaxmiddie
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Why exactly was this needed or helpful?
BTW- Welcome to the forum 8)
BTW- Welcome to the forum 8)
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jackssmirkingrevenge
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Nothing better than a few photos and/or videos to back up your humble opinion and lend more weight to your argument 
hectmarr wrote:You have to make many weapons, because this field is long and short life
You have much to learn, young grasshopper
Welcome to the forum. If you have this launcher of yours, post it in whichever showcase is appropriate.
Welcome to the forum. If you have this launcher of yours, post it in whichever showcase is appropriate.
Spudfiles' resident expert on all things that sail through the air at improbable speeds, trailing an incandescent wake of ionized air, dissociated polymers and metal oxides.
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SpudBlaster15
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Last edited by SpudBlaster15 on Wed Jul 14, 2021 6:29 pm, edited 1 time in total.
Yes the 20# fire extingisher is the correct chamber but I use mine to build a pneumatic....it is allmost finished. I am going to epoxy the fitting to the chamber just for good measure.
have it posted in a day or so..
have it posted in a day or so..
While we're on that topic, O<sub>2</sub>/MAPP is better than O<sub>2</sub>/C<sub>4</sub>H<sub>10</sub>, ski poles aren't very good ammo at all, and I really doubt that such a small launcher running on atmospheric pressure O<sub>2</sub>/C<sub>4</sub>H<sub>10</sub> could put a projectile like a golfball through a cinderblock and 2 bricks without some very odd circumstances in play.
Once again, seeing is quite a bit closer to believing than is reading, so we want videos, or at least pictures.
Once again, seeing is quite a bit closer to believing than is reading, so we want videos, or at least pictures.
Spudfiles' resident expert on all things that sail through the air at improbable speeds, trailing an incandescent wake of ionized air, dissociated polymers and metal oxides.
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jackssmirkingrevenge
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The're probably thinking of firearms, this is the general idea behind the taper or squeeze bore gun as used by the Germans in their sPzB 41 anti-tank gun.SpudBlaster15 wrote:Sorry for being the Physics Nazi, but that is a misconception too many people seem to have.
hectmarr wrote:You have to make many weapons, because this field is long and short life
No, a lot of people I know have thought the same thing, and they're hardly firearms savvy.jackssmirkingrevenge wrote:They're probably thinking of firearms
People just imagine that force from pressure can just be concentrated down, thinking that the imaginary "lines of force" will the air flow path - which isn't the case.
Does that thing kinda look like a big cat to you?
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Jared Haehnel
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You need more details... Is it pure O2 and butane? Is it at atmoshperic pressure or is it a pressurized? Do you have pictures? Can you take pictures...
Honestly I just can't see a golf ball going through concret bricks, the out side shell is the hardest part of the ball..if you remove that you just have giant boucy ball...
And Ragnarok is right... the pressure isn't concetrated just becuase the object is smaller... the only advantage you have over using a small barrel is you generaly have lighter ammo and greater vilocitiescompared to a larger bore... but that doesn't include sabots
Honestly I just can't see a golf ball going through concret bricks, the out side shell is the hardest part of the ball..if you remove that you just have giant boucy ball...
And Ragnarok is right... the pressure isn't concetrated just becuase the object is smaller... the only advantage you have over using a small barrel is you generaly have lighter ammo and greater vilocitiescompared to a larger bore... but that doesn't include sabots
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jackssmirkingrevenge
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hectmarr wrote:You have to make many weapons, because this field is long and short life
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Jared Haehnel
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I ment with the design he had presented...the velocity would not likely be high enough...Jared Haehnel wrote:
Honestly I just can't see a golf ball going through concrete bricks
I can