Hey VB sorry to leave you high and dry this morning bud but had to go tend to the gardens
Well here's the thing man..I have done so many dam experiments since I started making BHO it boggles my mind how much time I have spent comparing strain to strain and theory to theory etc. The main thing is that some strains WILL NOT WAX once you take the oil over a certain temperature. I have proved this running the same exact batch at different temperatures and only in as little as 5F degree variance. For example True OG Kush from the Cali Chem Dawg cut WILL NOT WAX over 115F period. The same goes for a recent Jack Herrer cross I ran and did multiple controlled experiments with to prove my theories.
Indicas (and the more pure they are) will very easily wax sometimes in only a few hours on a large thick run at as low a temp as 95F-100F. Hybrids are a whole different ball game with differences in waxing abilities big time.
Once your temp gets up in the 125 F and over (especially 130F and over) your chances of a strain NOT waxing increases dramatically. Yes you can be lucky and have a stain that will wax up there at those temps but trust me there are a lot (especially hybrids that are more sativa dominant) that are much more fragile and just won't wax at that warm of temps.
I have the benefit of having access to endless amounts of mj and tons and tons of strains to experiment with due to contacts I have with growers, compassionate clubs, dispensaries etc..
The thing is that if you went over that "magical" temp during those 8 hrs of night time un-attended purging then you may have cooked the oil too much for it to be able to wax any more.
There is chemistry involved there but that is the layman's terms to it.
And yes as the other guys said older material definetely increases your chance that the oil won't wax either.
I asked you several times in our pm's together if you have a laser temp gun but you didn't answer. I ask that question because it is very important. If you can not tell what the surface temperature of your oil is at all times during your purge then it isn't even worth running the oil because you need to be 100% certain what temp your oil is at every minute of your purge.
One thing to note though is that if you do not have any signs of a little fogginess or thickening of your wax then I think you may not even be at that stage yet. Cause usually if you will get some to form even if you go over temp. You have to be patient too and let it run at those lower temps for a good long while before attempting to increase the temp at all to make sure you don't over do things.