I cant really afford a proper rotovac atm so I’m using a cheap distillation kit from amazon to recover ethanol. It works just fine with no vac but I want to recover under low temp vac for color. When I hook my vacuum up to the receiving elbow and flip it on I almost immediately get a steady stream of wash coming through the whole system. I cant seem to find a definitive answer to this but I think this indicates a substantial air leak in my system correct? If its sealed nothing should come over until it starts condensing?
Do you have a vacuum gauge hooked up to your system?
At 40c your ethanol will boil real quick when you apply vacuum to it.
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Can you upload a pic of the system you are using? Generally rotary evaporator systems include a vacuum regulator and a cold trap. The regulator is crucial for controlling your vacuum depth so you do not boil your ethanol too hard - this may be why you’re seeing ethanol travel through the system you’re using. The cold trap ensures that you do not get any of that ethanol into your vacuum pump which is important for both safety reasons and for not destroying your pump
Edit: you can definitely get by without the cold trap, but you will want to be sure your condenser gets very cold (-30C ideal) and has fairly large surface area. Not sure a small condenser on a SPD is going to get the job done for you
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not on my distillation setup no, just my vac chamber lid. This is super small scale and pretty ghetto. Im running this (below) hooked up to a cheap harbor freight pump. Didnt think a gauge it would be necessary.
I flipped on the vac at 30C, it started bubbling like crazy for sure, enough to go over the elbow, but its definitely not warm enough to be boiling.
When you reduce the atmospheric pressure you reduce the boiling temp of your solution. An unchecked vacuum will boil that at 30c no problem. Were you throttling the vacuum or just letting it run?
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Zoom in on the pic. Does your pump have something like the little black lever there that allows you to control the vacuum?
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I’m a bit financially prohibited atm from getting a rotovac or I would for sure…but honestly we’re only talking about a couple of liters of ethanol ran a handful of times a year. Im just a med patient with a couple of tents trying to use his trim as efficiently as possible. I’ll never had enough starting material to play along with the small-time guys here let alone the big buys lol.
I have a small cold trap coming as eventually I wanted to play with spd but didnt think 35c with a cold condenser would really necessitate a trap, especially since I replace oil after each run since its a cheap pump. You disagree?
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I boil off the last of my ethanol after the roto the same way you are doing. It’s easier to pour from the roto with a bit of alcohol left in it. That valve on the pump is my best friend during the process.
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I dont believe mine does…this is the one I got.
https://www.amazon.com/gp/product/B07CPYDQN6/ref=ppx_yo_dt_b_asin_title_o09_s00?ie=UTF8&psc=1
(mine actually didnt come with the dual inlet adapter)
I know its cheap and crap but its just used to run my buschner, vac chamber and solvent recovery. I did want to play with SPD eventually so im hoping its good enough to run a small 100ml setup well enough but I doubt it.
You can add a valve on the hose from the pump to your setup. It will help a lot. I also doubt that will run an spd the way you would like it to.
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So I really am showing my noob colors here…
I went back to it and turned it on again to see if I could isolate the leaks.
This time, I just immediately started getting continual drips, no big flow. I put a piece of white paper underneath the receiving flask…clear. My thermometer isnt even reading 30c yet. This doesnt look anything like when ive done this without vac lol. It looks like its barely warm, no condensation that I can see…but it seems to be working?
Also a little concerned about the vac. I put blue pump oil in there and its already kinda milky and we’re not even 100ml in.
I’ll report back when its done if nothing blows up lol.
You really should have a cold trap. When I’m in a hurry I clean almost as much alcohol and terps out of the cold trap as there is alcohol in the receiving flask🤷♂️
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Im definitely going to use one next time. It’s on the way now. Thank you by the way, you guys have been awesome today.
More weirdness with the pump oil… when I first started it turned milky blue and was exhausting noticeably within about 5 minutes. I reused an old 4" inline fan and put a hose right by the exhaust and rigged it up another hose pointing out the window to vent it outside.
(hopefully it doesnt kill the fan but oh well)
By the time I got all that rigged up, I looked in the oil window and it looked fine. Clear and blue. I don’t know lol.
Still getting a steady drip of ethanol back and its perfectly clear.
I think that issue at the beginning was because of not ramping pressure up slowly. Going to get add a valve to the pump inlet for sure.
I’m unsure what happened with the pump oil. I assume it was ethanol in there obviously but maybe some of the ethanol impurities in the oil get exhausted from the pump? Its definitely exhausting much less now. I have no idea how it went from clear to milky to clear otherwise.
Thanks again everyone for answering these basic questions. I’ll be sure to pass it along to the next beginner.
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Yeah, blowing that exhaust out is your best bet. When you add that cold trap you’ll see just how much ethanol was making it to your pump.
Maybe read the whole thread.
Yeah, you don’t have a rotovap (I read that). Doesn’t mean knowing how to control one wouldn’t have helped here…
There is also the issue of solvent in your pump oil. Not good for you or the pump.
They don’t always become vengeful flame spitting creatures when you feed them nothing but ethanol, but it has certainly be documented.
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Well it was a fun day of learning.
I was able to get the clearest, lightest extract ive ever made. Made quite a few mistakes as people have pointed out (appreciate it!)
One thing I thought was interesting is how so many people here have said that doing this in such a small scale that you don’t really need a trap. Im not so sure about that after today. This pump freaking DRANK this hooch. I need to measure but I think I only reclaimed maybe 75% of my solvent at best. I definitely will not be doing this again without a trap. That’s just far too much loss and the smell was terrible. Impromptu fume hood seemed to work fine though. Fan still works too.
It was actually pretty smooth sailing after the first 20 min or so. My only major problem was right at the end. I was only using an ounce of trim since this was the first time using the vacuum so my yield was TINY. I went to a 50ml flask for the last part of the distillation and apparently just forgot bumping was a thing. It bumped way too high (duh its a baby flask, not sure what I was thinking there) and pushed crude into the condenser. After that I put the remainder in my 500ml RBF as that was the smallest one I had besides the 50.
Got the crude down to probably about 5-6ml but then it bumped a handful of times and just coated the entire 500ml with nearly finished crude which I could never really get off. Since the run was tiny to begin with, there went a good chunk of the yield.
I did my best with a heat gun and a ring stand but probably only got about half of it out. It was starting to get too dark under the heat gun so I’ll just wash it with ethanol and add it to the next run. No biggie.
Not really enough of a yield to bother putting it in the vac chamber but I learned a lot which should prepare me for the much bigger run I’ll do when the new supplies get here.
Ive ordered a 100ml and 250ml RBF along with the cold trap which is on the way. Also trying to find a inexpensive 100mm vigreux column (that wont take 2 months to get here) as I believe this should resolve any remaining issues with bumping causing flooding of the condenser.
I’ll make another thread next time if anyone’s interested in these super small scale runs. Ive improvised all kinds of neat little ghetto processes to try to mimic what 'yall do at a like…1% scale lol.
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Definitely using one next time….live and learn.
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You can also just use a fan at rm temp if you don’t want mess with recovery of such small volumes. It’s the kinder gentler version of a rice cooker
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whats your end product goal here?
Carts.
I know I know (go back to reddit kid)… but I just really enjoy carts and it’s the only thing I haven’t been able to produce on my own.
I don’t really produce enough biomass each harvest to justify SPD runs yet so I’m going for ethanol “shatter” …don’t really care about the consistency since I’m going to decarb anyway.
Essentially if I wasn’t a cheap bastard I’d have just bought a source turbo and a vac chamber. (Probably a better idea for people in my situation but with a little more money)
Been making my own carts for a while but in my state legal d9 concentrates are like $60 a gram and disty carts are $50 for half grams (Illinois) even for med patients. I don’t trust BM concentrates around here.
Hence why I’m even bothering with this at such a small scale. If I were in a state with affordable meds I wouldn’t bother.
The long term goal is to learn enough at small scale to network with a few other growers around here and pool our biomass for full disty runs.
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