Even at 32F you have to pump it in with pressure for it all to condense. Pressure at 32F is ~25psi for R12, I believe. I've been wrong before FWIW. I use a refrigerator pump turned into a vacuum pump that according to others can be used at the outlet end to pressure fill an approved container (cylinder, rather than a can due to pressure) when evacuating an A/C system.

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The Golden Rule

1984 300SD (bought new, sold it in 1988, bought it back 13 yrs. later)