According to this website
liquid CO2 is minus 192 degrees F
I have a few old CO2 extinguishers full laying around , however my understanding is that a syphon feed tank is needed to get liquid out and they are not that.
Since the mechanism easily unscrews from the thank with a large standard pipe thread, I'm considering taking an empty apart and putting a bottom feed pipe in , then refilling it from another tank or if this refilling isn't practical, it could be commercially filled.
I am aware the local welding supply sells liquid nitrogen at $7 a litre into the buyer's styrophone container and its somthing like minus 340 degrees F.
I got a pickup truck load of old CO2's and would like to have deep chilling capabilitys always available.
Anyone have any experience or thoughts on the practicality of this ?