Rotavap Parts

I’m building a small scale rotary drier/decarb reactor out of some rotovap pieces and a pressure cooker.
Anybody know where I can get a condenser nut for a Buchi Re111?
Trying to find rotovap parts is not easy.

Pic of piece?

It is the big round nut that screws onto the rotovap body to hold the condenser assembly in place.
About 3" across with a 2" hole for the glassware to pass through.
Made of plastic.
There are a ton of used rotovap bodies for sale on eBay and not a nut to be found.

Have you considered going straight to Buchi for one? No idea if their prices are reasonable but its probably cheaper than having a machine shop that deals with plastics make you one from scratch.

I have a few spare parts for a USALAB RE-1050 but no extra nuts and TBH a 50L roto nut probably won’t fit for what you’re doing.

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Try @Xtractek he seems to have buchi parts


I am unsure of a vendor/distributor that has that part without a thorough search online, but it appears as if the ‘condenser screw cap, 50.5mm’ part you are looking for was part number 00906 from Buchi. The wound style spring washer (called ‘insert spring or pressure spring’) that sits under it was part number 00590, and the combo of the two items was sold under part number 00676.

I say was as it doesn’t look like Buchi makes that RE-111 model new anymore, but I bet they are still using that part on a system that is still currently being made. A call to Buchi and they may be able to cross-reference a part number for you that is more easily found from online distributors (or they will have it themselves). On the Buchi website, they claim the RE-111 model was ‘replaced’ by the R-300 model, not the R-100 model, so maybe checking to see if the coupling screw for that unit is the same may bring results. I see different sites are each calling that part a ‘flanged screw, flange screw, or coupling screw/nut’ also, so a few different search terms may help haha.

I looked at my old Chinese 5L roto (RE-501) and the nut that hold on the condensing unit appears to be very similar to what I see described for the Buchi. Classified as a 50.5mm nut, which is about 2 inches on the inside diameter and 3 inches on the outside diameter as you mentioned. The thread pitch that accepts the nut looks to be about 3mm on the dot. That is 3mm from thread peak to thread peak. Maybe a similar measurement on your side will give you the confidence to try out a replacement for a Chinese model if you cannot find a Buchi replacement…