AC pressure readings (1 Viewer)

[cruiserfj45]

The little green ones.

 

[Wile E Coyote]

I've not looked at the small disposable tanks you mentioned, but I'd guess there's a capacity stamped on it somewhere per DOT regs. Look for "WC" followed by a number. The number is the rated 'water capacity' in pounds. As long as the total freon charged into your DIY tank doesn't exceed 'WC' (which equates to 70% actual capacity as I recall) you'll be gold.

 

[Wile E Coyote]

Maybe I don't understand, then... won't the tank be full of low pressure gaseous R-12 at the end of the fun? Its not going to return to a vacuum on its own...?

Not in my limited experience, but I used a boiling-hot water bath and kept it hot by refreshing the water as needed, along with starting the recharge with ambient underhood temps.