CO2 bottles

[snoo]

is there are problems associated with using fire extinguisher bottles for CO2
other than the ones sold for marine use [ is there anything in the metal cylinder which could react with CO2 and contaminate the tank ]

[graveyardworm]

Various gases tend to have different fittings on the bottle that would be probelm 1. The next and perhaps biggest concern for me would be is the fire extinguisher designed to handle the pressures that would be found in a typical full CO2 tank. On top of that i dont think you'll find a gas place that would be willing to fill an extinguisher with CO2. Again the fitting may present a problem here at the very least. I would nt do it. CO2 tanks for your Ca reactor for example contain very high pressure and could be considered a bomb in the wrong situation.