Co2 leakage chart

[HayleYoyo]

Hey guys,

I found this Gem! It's a list of plastic tubing, and their permeability rate with different gases. Anything with a number in the co2 column leaks. I just thought I'd share

https://www.coleparmer.com/tech-article/tubing-selection-guide

[Dxpert]

Cool, how would I identify the tubing I have?

[lucius]

There's another link that gives a more definitive answer.

https://www.coleparmer.com/chemical-resistance

I've been using the Python silicon tubing from Big Al's and can confirm that after a while it does discolour.  This is usually when I need to swap out the CO2 tank anyways so I just replace all the tubing.  I have used the polyurethane tubing but it's very difficult to work with because it's so stiff.

[charlie]

In regards to co2 permeability for our uses, most flexable tubing with the correct dimensions will do just fine.
The short runs and low flow after the needle valve renders permeability a non issue for most of us.
The higher the permeability number on the chart the less permeable the tubing is.
I have settled on using regular vinyl air line tubing since it is readily available and cheap, the con to it is that with time the exposure  to co2  will cause it to harden  and prone to leakage at connection points .
I just switch it out once or twice a year.