Page 3 of 5

Posted: Mon Jun 26, 2006 11:20 pm
by carlbelcher
It is 3' x 3' x 8" with a welded steel frame and two 48volt 20hp Briggs and Stratton “E-Tek” motors. The front and back is made of steel “C” channel that alone weighs over 80 lbs. It was a top speed of over 25mph and goes 0 to 25mph in less than 2 seconds.

Posted: Tue Jun 27, 2006 3:42 am
by Benny
D-Roc wrote:Hmm. Gives me MANY ideas. I didn't know CO2 comes from dry ice...

Question is how much dry ice do you need?

One of my friends has a chunk of dry ice the size of a bucket. I'll ask him for some...
you need a VERY small amount, i have made *cant discuss* and you only need a small ammount to make a soda bottle explode, add some water to get it to sublimate faster (from solid to gas).

Posted: Tue Jun 27, 2006 9:53 am
by pneumaticman
how would u mount the valve? it would have to be really sturdy for that kind of psi so probabely a metal valve that was welded on and where would u get a metal valve that wouldn't let all the pressure out at once?
or how would u make one? i think before u make this u should find a way to make it reusable.

Posted: Tue Jun 27, 2006 9:54 am
by pneumaticman
how would u mount the valve? it would have to be really sturdy for that kind of psi so probabely a metal valve that was welded on and where would u get a metal valve that wouldn't let all the pressure out at once?
or how would u make one? i think before u make this u should find a way to make it reusable.

Posted: Tue Jun 27, 2006 9:54 am
by noname
Some guy in my friends class filled a plastic bottle about halfway with dry ice and it didn't blow up so he ran over and shook it up. He had no palms on his hands left.

Posted: Tue Jun 27, 2006 10:13 am
by Bluetooth
Do u mean the skin ans muscle was ripped off all the way to the bone? :shock:

Posted: Tue Jun 27, 2006 9:37 pm
by noname
There was some muscle left but not much. And pneumaticman, you could put a threaded steel ball valve on one end and a threaded end cap on the other end. Just have a male threaded peice sticking out of the chamber, screw the ball valve on, open the ball valve, shoot the gun, close the ball valve, disconnect it, and screw on a different canister.

Posted: Wed Jun 28, 2006 10:35 am
by Bluetooth
That sounds like a pretty good way to do it but you would probably want some type of valve or some thing that would pop off or stop flow when it got to a certain presure so you dont blow the chamber and so the presure is more controlled.

Posted: Wed Jun 28, 2006 11:44 am
by boilingleadbath
Some valves are rated for pressure in that area.

Anyway, yes, the CO<sub>2</sub> liquifies at 800-900 psi.
I'm not sure that table is for our generic steel pipe though... are you sure it's not for stainless? I seem to recognise the numbers and table layout.

Posted: Wed Jun 28, 2006 2:51 pm
by noname
Bluetooth, that's exactly why you experiment on how much dry ice gets your chamber to what pressure.

Posted: Wed Jun 28, 2006 4:10 pm
by djt
well i still wouldnt want to be experimenting and somehow getting the pressure too high. like bluetooth said just put a pop off at the max pressure you want it to get to (or a little below the max pressure of the pipe). pop offs let out all the pressure when it gets too high right? if they do then is there one that would only release pressure until the pressure got below the pop off point?

Posted: Wed Jun 28, 2006 4:20 pm
by D-Roc
You don't need a pop off valve if you know how much dry ice you need. I'm guessing a 1cmX1cm chunk of dry ice is about 50-100PSI...

Posted: Wed Jun 28, 2006 4:25 pm
by djt
well what im saying is if you had a pop off valve that would pop at say 1000 psi and you went over 1000 psi it would only release pressure until it got back down to 1000 psi, there would be no need for any calculations. just throw in a bunch of dry ice and it will always end up at 1000 psi.

Posted: Wed Jun 28, 2006 8:10 pm
by noname
Yeah,that sounds good but they are probably expensive and where are you going to find one for like 800 psi? Mcmaster probably has one but it'll be very expensive there.

Posted: Thu Jun 29, 2006 8:43 am
by Bluetooth
I was thinking you could make one that would be enough to fill you chamber a few times so you could connect it and when it got to the right presure it would stop or pop off then you could shoot and connect it again instead of having a bunch of them.