Keep.on purging. Are you leaving the vac run constant, or stopping once you hit the magic -29.5hg? The vac pump should be running 24/7. Some purge for days and days and days on end.
I've tried this a few times now always seems to be waxy. The one time I had what seemed to be a good run going my vac pump pumped oil from the vac into my chamber. Ruined it all had about three grams going. Is a 3 CFM vac pump good enough.?
Yup, I'm sure almost everyone has done that at one time. Sucks not closing the right valve first and ruining a run. A 3cfm should work fine. It may just have to work harder to get the job done.