Page 1 of 2

200psi metal cannon Update:lots of damage pics

Unread postPosted: Mon Jan 28, 2008 1:13 pm
Author: bigbob12345
Okay well this was my first pneumatic. I made it about a year ago and back then I was worried about the pvc exploding so I made it out of metal.It isn't anything special but it actually is pretty fast if you pump it to 200psi.And don't comment on the ball valve I tryed to put a sprinkler on once it didn't make any difference in power probably because the volume is so low it just dumps it instantly.I might try to get my hands on some dry ice that I can pop in there close the cap and wait for the pressure to get to 300+psi but that would require a pressure gauge which isn't currently on it.

the specs
Chamber:2ft of 1in pipe
Barrel:3ft of 1in pipe
Valve:1in ball valve
Fill system:Presta valve epoxyed into the endcap
Pressure used:100-200 psi hope to so make that 300psi

The pics

The gun
Image

The chamber
Image

The snow that caused me to miss school today :D
Image

Edit just for you ALHISGREAT
duct tape for the handle
Image

Another edit:Damge pics
I was surprised that it was actually able to do some reasonable damage.

Firing at a 2in thick peice of wood with a CO2 cartridge wrapped in duct tape to make it fit in the barrel at 160psi.
Image

Firing the same ammo at the same target at 200psi you can see the difference.
Image

More damage pics

Aww the snows melting
Image

The ammo Ive been shooting a 1in 4ft long wooden dowel
Image

The dowel in the gunImage

The damage with the dowel to 3/4in particle board all at 180 psi
Image
Image
Image
Image
Image

peices of particle board
Image

peice of 1/2in plywood before
Image

Pece of 1/2in plywood after
Image
Image
Very impressive damage for a gun this size.

Unread postPosted: Mon Jan 28, 2008 2:08 pm
Author: ALIHISGREAT
the tape covering the crack in the pipe must seal it well :D other than that its a very nice gun!

Unread postPosted: Mon Jan 28, 2008 2:12 pm
Author: bigbob12345
ALIHISGREAT wrote:the tape covering the crack in the pipe must seal it well :D other than that its a very nice gun!


the tape isnt covering a crack its just there as a handle because the metal is really cold and I didnt want my hands to get all cold.The tape is just an insulator and thanks for the comment.

Unread postPosted: Mon Jan 28, 2008 2:28 pm
Author: ALIHISGREAT
you should have used duck tape :shock: the most useful thing for... well everything :D is there any chance of some damage pics :?:

Unread postPosted: Mon Jan 28, 2008 2:29 pm
Author: nivekatoz
If you are going to use dry ice I would put a safty pop valve on it just to be safe....I think you can get them to any psi you want or you can add a adjustable pressure valve and than a safty valve to pop at like 200 or 300 psi......... :salute:

Unread postPosted: Mon Jan 28, 2008 2:31 pm
Author: bigbob12345
It doesnt really do any damage to anything but cardboard
And your right duct tape is the most useful thing for everything Ill go put some on right now :D

And nivekatox its hard to find pop off valves that go off at such high pressure.

Unread postPosted: Mon Jan 28, 2008 3:22 pm
Author: bigbob12345
Updade damage pics which did a lot more damage than expected and for you ALHISGREAT a duct tape handle and sorry for the double post.

Unread postPosted: Mon Jan 28, 2008 3:59 pm
Author: POLAND_SPUD
bigbob12345 wrote:It doesnt really do any damage to anything but cardboard

hmmm.. you know I had a similar gun sometime ago and it was quite good at destroying stuff..I mean reallly good..
so I assume that there is something wrong with your gun.... possibly you are opening the ball valve to slow.... I had the same problem and there are quite simple ways to overcome this:

First of all put the ballvalve handle vertically not horizontall as it is now (so that you can pull it like a trigger and it won't affect you aim so much)
Secondly try to apply silicone oil inside a ball valve it really makes it fast and easy to open/close....
Finally use longer barrel - 150 - 170 cm would be good (and heavy as hell) - this would help you to minimize the effect of slow opening time...

ohhh and one more thing - dry ice seems like an interesting idea but you shouldn't try that without a gauge...

Unread postPosted: Mon Jan 28, 2008 4:05 pm
Author: bigbob12345
Yea Ill go get a gauge next weekend and a longer barrel when I get some more money. Ill go make the ball valve vertical and lube it.I can get dry ice for free because my dads a scientist and they got lots of dry ice at his work so it seems like a good idea.
And that part about it only destroying cardboard I proved myself wrong ten minutes ago when it went straight through a peice of 1/2in plywood

Unread postPosted: Mon Jan 28, 2008 4:38 pm
Author: ALIHISGREAT
i like the new duck tape handle and the damge is pretty impressive :wink:

Unread postPosted: Mon Jan 28, 2008 6:16 pm
Author: DYI
You can try dry ice without a pressure gauge. The maximum pressure it will reach at room temperature is around 900 psi, perhaps 1000 if it is hot (which it won't be, it'll be damn cold actually). The burst pressure of your chamber is over 3000 psi, give or take, but the CO2 will never break it unless you drop in the dry ice and throw the whole thing in a fire. All you would need is a higher pressure rated valve. The crappy hardware store ones are designed for liquids, and I've had them leaking horribly at 400 or 500 psi.

And if your dad has that kind of thing just lying around, you need to try liquid nitrogen, not dry ice :twisted:

Unread postPosted: Mon Jan 28, 2008 6:37 pm
Author: bigbob12345
Okay this weekend Ill go get a bunch of dry ice and possibly some liquid nitrogen(my dad has acsess to it)Ill get a union so I can have a ball valve actuated burst disk gun.I will get some 1.5in pipe to expand the chamber and a 10 ft long 1in possibly 1.25in pvc barrel so I can max out the power on this thing.I will get a pressure gauge cause I wouldnt feel safe putting 900psi in it I will probably max out at 400psi.Ill go Upload some more impressive damage shots now.I also altered the gun around a little and lubed the ball valve for faster opening time.

Unread postPosted: Mon Jan 28, 2008 6:49 pm
Author: DYI
A gauge is mandatory with liquid nitrogen. The pressure it could generate is in the 10,000psi range. And sticking to 400 or 500 psi is probably a good thing. The steel isn't weaker at low temperature, but is more brittle, and steel shrapnel is quite a bit worse than PVC.

I would be a bit worried about LN2 with the current valve though. I wouldn't be surprised if it was damaged beyond repair by the temperature of the gases generated. If you plan on liquid nitrogen, a separate expansion / heating chamber may be a good idea.

Unread postPosted: Mon Jan 28, 2008 7:21 pm
Author: bigbob12345
Update lots more damage pics
And DYI if useing liquid nitrogen would require all those things than I dont think Ill use it rememper this was my first pnuematic so I just want to keep it simple here.Im also on a low budget (8-13 bucks a week)so I think Ill stick with dry ice.i made this a year ago and just today realised its potential to be the next SCBTCD.

Unread postPosted: Mon Jan 28, 2008 7:24 pm
Author: bigbob12345
Update lots more damage pics
And DYI if useing liquid nitrogen would require all those things than I dont think Ill use it rememper this was my first pnuematic so I just want to keep it simple here.Im also on a low budget (8-13 bucks a week)so I think Ill stick with dry ice.i made this a year ago and just today realised its potential to be the next SCTBDC.