Piecing together a small SPD - what do you think?



You guys want a standard taper to kf flange?
Pm me if you need anything!


Great, thanks! That’s the type of solution I was looking for!


I use a vacuum still I got off Amazon for $200. I don’t yet have a mantle so I used a flat bottom boiling flask and a hot plate. It’s a painfully slow process with my setup, but I would imagine a mantle would make things easier. My recovery time is about 1-liter every 2 hours. A rotovap would make things so much easier, and is definitely on my list in the very near future.


Out of curiosity, what would be the problem with using the SPD with a cold condenser for solvent recovery at this scale? Is it just the inefficiency of having to remove the BF and add more winterized crude, or the long residence time?


All of the above. There’s nothing wrong with it actually. Just takes a painfully long time. But, if you have a couple hours each day after work and you can get what you want done by the time you get a chance to run it. It’s function was served, and you didn’t do it wrong.

Decarbing will be a pain in that small chamber


Makes sense. I want to decarb as a separate step so that I can retain half of my crude as predominantly CBDa for a few experiments, then decarb the other half and SPD it.

The GLG sop for decarbing says to do it at 140C, and I would run that small electric still at about 80C for ethanol recovery. Will decarb occur for the long residence time in the still even at 80C? Or will it be a small conversion? Doesn’t seem to be an issue in a rotovap (which is pretty gentle), not sure how much different a still is.


Decarboxilation is a heat reaction
Evaporating under vacuum at low temps (35C) has No decarboxilation


I think I figured out what I am going to do for the mantle.

I’m going to buy this fabric mantle and use fireplace rope/aluminum foil to insulate the top: https://www.amazon.com/Glas-Col-100A-O408-Hemispherical-Capacity/dp/B0048LJYRC/ref=sr_1_3?ie=UTF8&qid=1547273370&sr=8-3&keywords=fabric+heating+mantle+1000ml

Power/control temp with this Variac:

Stir plate:

Is it necessary to measure the temperature between the mantle and the glass with a thermocouple?


@Dred_pirate Obviously I’m not going to pay an extra $170 for a $50 submersible pump and steel bucket, but is this setup similar to what you were talking about with making your own chiller for the distillation? Just set it at 80c during the body fraction, yea?



Exactly. You can also get a gormia sois vide for less than $100 and they are technically more powerful than the polyscience.


Oh that is fucking excellent. :grin: Thanks! Do you usually just use an ethylene glycol mix or would straight water suffice?


If you could keep a lid on so the water doesn’t evap too fast, I bet it’d hold up. I wonder if it would handle the glycol well. Hmmm.


Are any of you guys modding the cheap China mantles with better temp control?


yeah, Ive done that a few ways!


What has been the best method? Wire the heater to an external PID?


You can add a better internal thermocouple, replace the pid with a better one, or run a variac.
You can also upgrade the motor controll for the stirring.


I can get the 2l and 5l China stir mantles cheap just wondering if with a few upgrades they are worthwhile


I’m ordering some stuff right now and was wondering if the placement of the vacuum pump is critical. I notice a lot of people placing their vacuum on the ground and running bellows from it.

Is there a downside to elevating my vacuum pump so it is level with the outlet of the cold trap and then connecting the cold trap directly to a tee which goes straight to the pump valve?


yeah, they are worth it. Its hard to make a bad heater!


I use this model for my CLS and it works awesome.