One thing to think about, depending on the amount of"ice" you're using, It will cease to sublimate once it reachs roughly 850psi(depending on temp), even with heat, once the critical pressure is attained it will just melt as opposed to sublimating, and become supercritical co2, and when you open ...

CO2 is almost three times as dense as air. Molar mass 44g/mol. Air is mainly nitrogen and oxygen, which have molar masses of 14 and 16 g/mol respectively.
Nitrogen and oxygen are diatomic!
This means the molar mass is twice the elemental atomic mass, which means air's mean molar mass is 28.97 g ...

With CO2 (half as dense again as air), it's not surprising.

CO2 is almost three times as dense as air. Molar mass 44g/mol. Air is mainly nitrogen and oxygen, which have molar masses of 14 and 16 g/mol respectively.

In terms of how much ice i'm using per shot, well its a fair bit. Im not ...

I'm back with more of my dry icing.

http://www.youtube.com/watch?v=rw_qsoQ-3Rg


After building a PVC dry ice cannon, http://www.spudfiles.com/forums/viewtopic,p,243398.html#243398, i decided that continuing with PVC was too dangerous, due to the temperature sensitive nature of PVC.

So i made ...

Dry ice and plastic pipe. It just doesn't sound right. Oh, you know the dry ice will produce pressure at different speeds depending on water temp of course. So how can you know how fast it will evaporate? You mentioned hot water. Did you use cold water before? Theres too many things to pay ...

Yeah I've got teflon tape already for the current one. And yeah when I go steel i will make up for lack of a burst valve with massive pressure.

Hmm so I still won't have issues using hot tap water so long as i don't use too much dry ice.

Sounds like the go though (I can fill metal with lots of hot water and shitloads of dry ice XD).... so a few more questions on doing this with metal.
How much is malleable iron gonna cost?
How is the ...

While PVC becomes more brittle a lower temperatures, it also increases it pressure rating. Hot PVC can handle a LOT less pressure than cold. Brittle just means if you drop it (and in doing so exceed the stress limit) it might explode.

At 60*C the rating of PVC pipe falls to just 22% of its stated ...

lol sorry I'm australian and we get taught metric units at school

And no, it isn't safe! While 2000kpa sounds like a lot, it isn't. No where near enough for carbon dioxide (unless regged). Dry ice will also make the cannon VERY brittle so take caution. A pop off valve and a gauge would be a good investment.


This was my concern when i started out. I'm aware of ...

Hello All

Thought I'd share my first ever attempt at any sort of cannon. I got the idea from dry ice devices , thinking that it'd be a pretty good way of generating pressure for projectile. So here's my setup. About 1.5m of 40mm uPVC Gas Pipe (rated to 2100kPa), sealed at one end with an end cap ...