don’t let me talk you out of it 
see-through is nice.
stainless is more efficient.
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I think you would achieve the same heating surface area as you would in a fixed boiler with an agitation mixer.
I think the reclaim rate and efficiency is also greater on say a double jacketed boiler with a shell in tube exchanger. There is a guy here that recently built a keg pot still with a shell & tube exchanger I would have to find the thread
falling film also has no stupid rotary seals
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id recomend you do some research on rotovaps, and understand their purpose, otherwise everyone would be using stills.
this thread is to foster ideas about rotatory evaporator designs, not stills, if you’d like to create an agitated still, go right ahead. i am looking for something a bit more delicate.
the ultimate purpose for a rotovap
so community dev of the
would go to good use eventually 
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this seems like a really useful bit of lab equipment
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terpenes!!! 
I just bought my first rotovap and I am excited to get to use such a nice evaporation unit vs evaporating with heat and a stove
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Okay, how?
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Given that the rotary seals are the difficult part, I’d start with a Rotovap…
Eg:
And @downtheterphole is correct that a diy FFE has many of the advantages a Rotovap does over a pot still (it’s also a thin film evaporator) and is missing that pesky rotary seal.
Additionally they are easier to set up in continuous duty that a Rotovap…
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Build a falling film instead. If you’re focused on solvent recovery, build a small one of these with off the shelf parts, or if you need more exotic parts, weld them (or hire someone), but these are very simple in their design; rotovaps have many limitations and are slow you will find!
One of the hidden cost of solvent recovery is chilling. Get the most powerful chiller (in terms of cooling capacity… kw or btus, not temperature).
I was designing my own falling film (cheapest one I could buy was 175,000!) so I designed one with parts I could buy for only 35,000. Half of that was the chiller, 10,000 for the actual steel, 2,500 for the heater and the rest is little stuff.
Does that unit pictures include the seal? I have a old buchi r-110 that looks like that sans the vapor duct.
Still don’t really understand how it all goes together to allow it to spin under vacuum.
Edit: I’m going to post a more thought out question once the coffee kicks in……
no clue. I’m in the “build an FFE instead” camp.
although I’ll work with whatever is lying around at the time 
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if you’re going to build a rotovap, I really do agree with the above. start with a rotovap.
I originally bought a no brand 1L roto on eBay for 600 new.
after some time with it I decided I wanted to upgrade. I also had a broken vapor tube. so I ended up finding a replacement for that and a round bottom 5L that attached. down the line, I might outfit it with a new condenser but I find that keeping the chiller cold and the vac at proper levels is how you optimize recovery rate.
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Though it was build, not buy a used one.
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1st order of business is the rotary seal.
If you’ve got a rotary seal design you want to try or share, please don’t stop on my account.
If you don’t, you’ll get further down the road starting with a salvaged seal. It doesn’t need to come from a Rotovap, but that IS the easy place to look.
Stainless has enough advantages over glass that such a build would likely be a win.
You may or may not be better served by an FFE…
Depends on what you actually need.
Edit: @Rowan was playing with ferrofluid seals at one point, and might have a place you could go looking.
You’re looking at a 3year old thread.
Most of the folks around here that I would label as “up for this” have instead built FFEs.
Take from that what you’d like.
And check out Optimizing your RotoVap
Eg: Optimizing your RotoVap - #250 by SidViscous
And
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The cost to put together a little dinky rotovap
(An antiquated design in terms of thin film evaporation)
Is rediculous, when compared to the cost to build a benchtop falling film.
With that said….
I will be presenting my own fusion of timeless tradition and modern innovation before the clock strikes 12 tonight.
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So it was detmined that this midnight thing was not correct.
I didn’t like the way it was oriented so i added some more bends
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