So, a person should change the oil between first pass and second pass?
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I’ve always had the worst luck with thermo adapters. I swear by thermowells now… but you must know your stir bar really well so as not to let it loose it’s path. Otherwise the thermowell can shatter… and I can only imagine the mess and cleanup process for that.
But for thermoadapters I’ve recently came across a solution. Summit has a new adapter. I had minimal luck with the adapter initially but I think there was some design flaws specific to the one I got. A difference of 0.2mm on the glass thickness caused the o ring to slide in. I got a new setup and I’ve yet to try it but but what I know is that the o rings will form a memory and shrink often times. So it’s always important to remove the oring soon after the run is over and set it aside… allow it to reform. Also… if you grab the summit adapter the o ring is huge… but it’ll fit on common adapter. And the o ring should really hold well
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In my opinion… always. I’ve never seen a first pass run pump pull under 10 micron after a single pass… let alone 2-3 micron… most often it’s around 40 micron with warm oil… that will never get you to 3 micron on second pass which is extremely helpful for removing all of the heads fraction tightly
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Don’t use the probe that comes with the mantle, it should have come with a plug that goes into the side so you can use the internal sensor. I use a one necked flask, and control the mantle temp from the outside. Less joints to leak, plus the mantle can never overheat your material. Think of it like this, once the internal probe tells the heater to turn off the temp will continue to rise. This is because it is further from the heat source and inside our favorate isulator glass. When temp is directly taken directly from mantle it’s
Pid controller has instant feedback. Also no probes, no chance of shattering anything. Ramp up the distalation slowly until volitiles are starting to reflux in the head, then run the apparatus by the head thermometer, just like any fractional distalation apperatus.
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If you slow down the pass the first pass you will reach a point near the cannabinoids where the vaccume improves, this is because most of lower boiling point components have left. Near then end of my run I don’t have to adjust the mantle heat to get thc, the vacuum simply improves until the boiling point has reached.usually less than .1 torr. The trick to getting a low vaccume and a good separation is removal of the lower fraction.
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My PID Control works best to hit target temp when I place the thermocouple sensor between the glass boiling vessel and the heating mantle at the midpoint of the boiling puddle sort of on the side. For me PID sensors in any PID application work best when they are closest to the source of power being controlled (the mantle itself). The algorithms used seem to predict things more accurately that way. For a horizontal run I place a thermocouple on the top of the glass at the neck too during the boil that is hooked to my yellow meter. The mantle controls the heat but the one at the neck tells me when cannabinoid will begin showing up in the first bulb. At ¾ of one micron when that top glass temp at the neck reaches about 132C I can see cannabinoid as a thick resinous material accumulating in the flask neck toward the exit into the bulb. At 140C it runs pretty fast and using time lapse on my iPad it looks awesome lolz. Running hotter makes it immediately darker.
Dialing this in is pretty easy when the probe is just outside the glass and between the mantle. I have tried other places but my PID Control has an overtemp feature to prevent mantle damage so the sensor must be in contact with the mantle for this to work.
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Amen on keeping it simple and rugged. I got my Edwards 28 from Craigslist. Three years old BHO purging pump. I drained the oil and I swear a puddle of terps not miscible in the oil ran out first as a seperate layer! The guy told me he had changed the oil once or twice lolz. I did two oil changes and it pulls down to rated blank off vacuum. It was beat up and no maintenance but hums along just fine for me. He delivered it for a $1000. Those are like $5000 new lolz. I use synthetic grade 20 oil. I also make a point to run copious volumes of air through it during and after the runs. I will not run the ballast as the volume and vapor generated is not acceptable where I live. So one second pushes on the vent button from time to time keep the micron reading from stalling. The fresh air through the lines seems to blow out the volitiles and it definitely holds tighter vacuums doing this.
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Check with the manafacture of the pump, but a great way to clean a rotery oil pump is a 50/50 mix of kerosene and pump oil. Run for 30 min with gas ballast open, drain, flush, and fill with new oil. Simple is best, the truest statement I have heard!
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Dam removing the o ring makes sense for sure. And I’ll def get one of those new summit adaptor and see how that goes. Will also be buying a bunch of o rings to have on the side. Thanks for the help. I did not get the o ring to suck in. More the o ring was too wide of a hole.
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Dam ok I’ll have to try that one no probe. I noticed the head temp was not consistent with the BF temp. Does the head temp probe need to be as far down the head as possible of more towards the condesner?
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The head temp probe monitors vapor temp, the BF temp is going to be higher, significantly so if your BF and head isn’t insulated/silvered
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Just use a standard ground glass thermometer in the head, immersion depth should place the bulb of the thermometer at the same level as the takeoff to the condenser. If you use internal temp sensor there is no need for the probe.
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Ok that makes sense thank you
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Ok I’m going to try the internal probe setup first thing Monday.
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I love the idea of using sonic agitation with absorbents. I’ve used that method for lipozomes and had never really thought of it for scrubbing. Cheers!
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@anon42519203 Can you explain why you prefer to do two passes? What are the key factors that improve with a second pass? You have a lot of experience in this, so I would imagine your first pass distillate is better than most.
Differences in potency? Improvement in odor? Color?
If you were restricted to a single pass what might you change? More patience during the heads fraction? I would think that going very slow or using dual distillation head pathways to really pull out the heads junk would in theory be able to create a first pass main body that needs no additional distillation to remove contaminants. I have made 90% THC on a first pass on a 2L, but holy fuck was it a slow process.
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Its typically alot easier to do two passes. The reason being mainly due to aZeotropes, and the mess that happens when volatiles go all over your system, and they do. The first pass is a rough cut. You remove alot pf unnecessary fractions. Doing this quickly can actually keep a very high potency result, ive seen personally as high as 99% on a first quick pass. The key was to allow a long heads fraction and clip the main body early before tails begins to appear. Theres a narrow window for this and it changes not only due to boiling flask constituents but also vac depth. As vac increases, the fraction separation tightens… so tails begins to catch up.
If restricted to a first pass only. I would have two heads if color was the only worry, but if it was color and potency… then a nitrogen backfill that filled just after the main body drop off like the port on the laminar cow from summit. That way as heads started what i would do is inject nitrogen like a distillation gate to kill the boil. Just enough. Then stop injection and allow some more heads to come out. Then do this again. And again until heads finished. This concept comes from the enrichment process of uranium 235… they used a series of diffusion mesh rooms where they would pass uranium hexaflouride from one chamber to the next. The way they do this is built on the principle of molecular distillation, the lightest molecules will move first through the mesh, in a rush, then the other molecules would follow, they would shut the gate on those and subject them to the same room. The ones that made it out first would then go to the next room and do it again… by doing this. Heads fraction could be stripped clean enough to remove most of it and then main body can be taken over… the issue is the nitrogen would ahopt stuff everywhere… including in the pump… which is another concern… the pump is full of junk after a first pass… youd have to have a volatiles pump and a main body pump or two…
Another way would be to subject the crude to all the preprocessing i could before starting… thus allowing for better results based on material.
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Low and slow does work… but multiple columns help, tall for azeotrope (heads) short for target… also vac depth can be a factor (working on diffusion setup, ive heard good things)
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Thanks for the thoughtful reply. Interesting stuff. So it sounds like a high purity first pass product is possible, but it seems like consistency would be a challenge due to the fluctuating factors, especially vac depth, between runs and within a run.
What do you put into the flask for your second pass? Just the main body of the first pass? Looking at your setup it looks like you trash all the heads and go next to main fraction, then swap out the flask for tails? I have been using a rinky-dink custom 2L I built with the 3 receivers. I collect a terp/head waste fraction, and early THC fraction I call “heads” that is stored separately, and then a main body. I don’t collect tails but retain the residue. I am aware of the limitations of this setup so I’m putting together something new. My crude is decarbed and partially de-terped so there isn’t an overwhelming volume of the terp/head garbage.
Also, you must change vac oil a lot. What are you doing with all of that?
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Depending on how clean the heads cut is alot of times i will garbage it. If theres alot sometimes ill collect them and throw them in with tails. I can usually clean all this up in a single pass with some clay and then bump trap any residual heads off like i did in the last video. The quantity of actual heads fraction i get is generally pretty minimal, and in the interest lf time saving and potency, i dont spend much time on them. Just collect and set aside… the run of heads and tails made enough for a 10L run initially. When i was done i had about 1500ml of actual usable material. So is it worth it in the end really… 
Ya after a few months sure.
The nitrogen backfill is still just a concept but it does theoretically work. I have monimal plans set in motion to try it.
As for the vac oil. Its hydrocarbon based oil… you can turn it in as motor oil. Technically. From what i hear it actually ends up as ship engine oil… thas at least info from the owner of provac
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