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 
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.
Though it was build, not buy a used one.
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
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.
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
Here’s a couple threads to chew on
Has small ffe ideas
Add your 2¢ I’m always looking for ideas.
Yes, that’s the underlying idea; The solvent evaporates faster due to being spread over a larger surface area inside the rotating flask.
I suppose the better question is what is the purpose of this is to ask what OP need this for (if they even care anymore). Is it for bulk solvent recovery? Is it general use? Or is it residual solvent recovery? Bulk is obviously an FFE, and you can make a small one with off the shelf parts for $1,000-$2,000. General use would be rotovap. Residual, you can actually get away if your temp is high enough (depending on solvent). Steel is always easier to handle than glass because glass sucks other than seeing what’s happening.
5L rotavap - R&D, smaller batch production
20L rotavap - Scale up work, medium batch
FFE - Large batch production
A rotary evaporator is indispensable in a chemistry lab setting.
I think it’s just nice to have something where you can harvest the oils easier than a rotovap. A rotovap is a BITCH!!! At harvesting oils. I’m still gonna build a FFE at some point. It’s just that even at a small batch with just doing a 1lb eho extraction. Using 3.3 L/1 gal of ethanol it’s more worth it to make a mini ffe. I think that mini ffe are the future and should be used at all costs.
You can literally get your solvent out quicker and left with an easier to remove oil in a ffe than a rotovap. Once I build a functional ffe that completely decimates the time my 5l roto takes to evaporate 3.3L then I’m going to store my rotovap away.
You can make many tweaks for cheap that will make a roto piss solvent, especially at your scale. They definitely aren’t the most efficient but until you need serious recovery i dont see the point, i can do more than enough in my 20L’s and decarb and volatile strip before i ever open it.
You could salvage a worm drive out of a skill saw or a pinion gear out of an angle grinder if you wanted to build your own rotovap
the vacuum rotary union seems to be the difficult part to source
it’s also possible I just don’t know the right combination of words to make google happy
That was the answer I got in the stainless rotovap thread.
The more you work with a rotovap, the easier it becomes. It is not uncommon for a rotovap to be fired up first thing in the morning, to run in the “background” all day long, and be the last tool to be turned off at the end of the day.
To some degree of approximation, the rotovap’s usage becomes an indicator of the chemist’s overall productivity.
Yup, you can set it and forget it!
Once you find a rotary seal, or make a halfway decent one, the receiving flask (if it isn’t a ground joint) becomes the leaky seal. Little trick of the trade for larger rotovaps (5-50L), is to use the rotovap clamps and cut the lip off one side of a triclamp gasket with a razor blade, you can make a very solid metal to glass transition that holds vacuum overnight.
32/50 flat glass joints fit a 1.5" triclamp
40/60 flat glass joints fit a 2" triclamp
For my 50L rotovap, the 2" triclamp flange goes to a hose barb, to hose, to a sanitary keg. This relieves strain from the joint, so your vacuum stays at pressure without an active vacuum
