12 gram CO2 adapter pressure & safety
Posted: Fri Jun 06, 2014 3:06 pm
Hi all. I have experience with pneumatic and combustion cannons, but I'm interested in using 12 gram CO2 cartridges and I could use some clarifications. I want to copy this design that I found here:
I understand CO2 operates at extremely high pressures, so steel parts are needed for the construction. I'm concerned about a few things:
1) The video (and the detailed construction plan) has no mention or warning about pressure ratings on the parts used. Are these parts, especially the unspecified ball valve, really safe with 800-900 PSI? Do I need to find a specific kind of 'heavy duty' ball valve or 'heavy duty' teflon tape, or is the difference negligible?
2) What's the purpose of the expansion chamber? I assumed it was intended to lower the pressure, but according to the wiki and relevant sticky, CO2 pressure from a 12 gram cartridge won't decrease until it fills a much larger volume. How would the design perform with a shorter/longer chamber, or if the adapter were just screwed directly into the ball valve?
3) What would a catastrophic failure look like? I know PVC shatters and explodes, but what happens to metal pipe and metal ball valves?
The video has almost two million views and I can't find any complaints about it, so I have to assume it works as pictured. I'm just cautious because the author spends more time discussing his launcher's paint job than describing the mechanism.
I understand CO2 operates at extremely high pressures, so steel parts are needed for the construction. I'm concerned about a few things:
1) The video (and the detailed construction plan) has no mention or warning about pressure ratings on the parts used. Are these parts, especially the unspecified ball valve, really safe with 800-900 PSI? Do I need to find a specific kind of 'heavy duty' ball valve or 'heavy duty' teflon tape, or is the difference negligible?
2) What's the purpose of the expansion chamber? I assumed it was intended to lower the pressure, but according to the wiki and relevant sticky, CO2 pressure from a 12 gram cartridge won't decrease until it fills a much larger volume. How would the design perform with a shorter/longer chamber, or if the adapter were just screwed directly into the ball valve?
3) What would a catastrophic failure look like? I know PVC shatters and explodes, but what happens to metal pipe and metal ball valves?
The video has almost two million views and I can't find any complaints about it, so I have to assume it works as pictured. I'm just cautious because the author spends more time discussing his launcher's paint job than describing the mechanism.