All you 68ers & 72ers, Whether it'ts boiling or de-gasing, you
want the bubbles off your castings. At 72 (degrees F right?) the
surfactants (soap) built into the investment has a better chance
of helping those bubbles lift off, especially with a marginal vac
pump, with a little higher temp. Have you ever noticed how your
clothes get cleaner washing them in warm water instead of cold?