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Posts I've Made
18 April 2008 - 08:10 PMThink to yourself, what am I offering to their company instead of what they can offer you. It's a business proposal, and you need to convince them to invest money in advertising through you.
18 April 2008 - 08:06 PMUmm...well no wonder it blew up. Did you do any research before you plugged all of this together? I believe you would have been okay if you had used steel piping, but there is no way a 1.5 diameter 12" long PVC pipe section is going to hold that much pressure.
You are a very lucky man
How much pressure is it really holding?
Been doing some math and this stuff isnt adding up...
800 (PSI Output of a 12gram) * 5.56 (volume of 12gram)=X * 21.205 (volume of the airchamber).
800 * 5.56 = 198.05 PSI in the airchamber
What did you say the pipe pressure rating was? That math was using Boyle's Law, yet I am pretty sure that since Co2 can become a liquid, it sorta screws the math/equation up some (as well as temperature)
Instead of using Boyle's, let's use the ideal gas law.
We have a 1.5" by 12" pressure chamber.
V = (D/2)^2*pi*L
V = 21.206 cubic inches
Google says: 1 cubic inches = 16.387064 cubic centimeter
16.387*21.20 = 347.499 cubic centimeters
Google says: 1 cubic centimeter = 0.001 liter
.347 L of space in the expansion chamber
CO2's molecular mass is 44.01 g/mol
there are 12 grams of CO2 in a 12 gram.
12/44.01= .273 mol CO2
The ideal gas law:
P*.347=.273*.0821*295.778 (assuming 73 degrees air temp.)
P= 19.1 atm
Google says: 1 atm = 14.6959488 pounds per square inch
19.1* 14.696 = 280.6 PSI
Therefore, we can see that the pressure in the pressure chamber was 280.6 PSI. However, the major issue at hand is not the pressure chamber, but rather the valve. Most valves are rated in the 100-150 PSI range.
What can we learn from this?
The pressure chamber needs to be larger. This entire fiasco could have been averted if the chamber was longer.
Working backwards, if we want the pressure in the chamber to be 100 psi, we would need a chamber of approximately 1 liter. This equals a minimum, safe pressure chamber size of:
2" X 20" or 1.5" X 34.5"
I will agree that it was foolish to use unregulated CO2. However, properly used, 12 grams are the BEST and SAFEST way of creating air cannons. They limit the available air to a SAFE pressure and do not have regulator creep or other negative affects.
I would also like to extend condolences to the poster and wish his safe return to health.
18 April 2008 - 07:39 PMFrom boy scouts, it's supposed to. I can't say I've tried it.
16 April 2008 - 06:00 PMMaybe try and use some clear coat on it? or something of that nature.
12 April 2008 - 06:19 PMI think it's fadding away... but not fading away.
It's becoming less of a fad, and has some lasting ability.