Tri-clamp Fittings Ultimate Vacuum Rating | Open-Source Shortpath

I’m looking at building a tri-clamp SS short path because I’ve about had it with glass in general. I’m tired of leak hunting, cleaning charred round bottoms with a contorted brush, and the general fragility; I don’t give a shit if I can’t see what I’m doing.

At first glance kf fittings seem like the way to go, especially with an ultimate vacuum of 10^-7 torr, but I’m not sure they’re suited for the task, especially with high volumes of vapors and high heat. They are also rather esoteric and hard to find in the shapes needed to build a short path, especially jacketed parts.

So that leads to tri-clamps. Does anyone know the ultimate vacuum rating of a triclamp fitting? It seems like they would be on the order of ~1 micron or so, and the only theoretical limit is the vapor-pressure of some low mw polymer in the gasket. The theoretical limit may be the gaskets themselves degrading and creating a vapor pressure (viton or PTFE would be the way to go then).

I know this is a bit of a lame question to ask, so to sweeten the thread a little, I’ll post a few rudimentary designs to make a pretty good still for not that much money!

4 Likes

I wanna see!

2 Likes

Why not use copper gaskets instead?

2 Likes

Tri clamp will hold vac, idk to what micron depth. KF flanges are purpose built for that though. send @AlexSiegel a message, he’s got some interesting stainless spd stuff

3 Likes


I got one of these just to play. Its got potential.

2 Likes

Tef-steel dude

3 Likes

A few departures from a regular still that I still think are valuable or neutral. Most stills are on a 30-degree tilt, this one is a 45, while perhaps not ideal, it may help the fishy smells pass through since vapors like to travel down.

Using a jacketed 1.5" bend as the hot condenser head because hot condenser tek is obviously important.

I also went for a jacketed ss spool instead of a heating mantle and flask because I noticed that when I would do a volatile purge in my rotovap at 140C, my oil would smell a bit flowery/earthy, but not bad. But once I used a bit of transfer solvent to get to my still and I boiled it out at only 78C and it smelled like the fishy terps we all know and hate. I realized that while my probe read 78C, the heating mantle fibers are actually well above 200C at any time and that’s causing that degradation. So, I found a 250C heating recirculatory and plan to use that instead for more accurate temperature.

I don’t have it here, but I have an AI -50 cold trap that I’m not sure how to design yet, but it’ll come with time. I’m also not sure how I want to drain the goodies whether that be by discharge pump, cow or a simple bypass flask. I also want to put a few bypass valves, so I don’t need to pull tubing off anywhere to bypass my cold trap.

8 Likes

What kind of fluid are you going to use for heating? Just wondering if you’re going to get expensive fluid or if there is a cheaper option im not thinking of that will do 250C

I’m probably going to have to bite the bullet and buy some silicone oil, maybe some mineral oils because this is closed, but I’ve degraded those before when it was open.

1 Like

I like to use glycerin as my go-to, but in this case it’s probably a bad idea since its flash point is 160C, also its viscous as hell and really dense so it can wreck a pump.

Tuff steel gaskets would still have the same problem as ptfe gaskets.

just use avocado oil and cook dinner in it at the same time

@AlexSiegel has a nice setup for sale.

6 Likes

Smoke point at 271C? :thinking: Not a bad idea, the main thing to avoid is running into the oil degrading when it touches the heating element, which I think cooking oil will. (I know it was a joke, but not the worst idea, I’ve used cooking oil for oil baths)

2 Likes

it was a semi serious suggestion. Really too hot to cook stuff in though and would definitely break your shit to have food particles running through your pumps.

i have no idea how quickly it would degrade at the heating element.

1 Like

Dynalene HC50

1 Like

Tef-Steel

And what problems exactly?

3 Likes

Gonna need to incorporate a stir mechanism of some sort

1 Like

I’ve found that when I forget to add a stir bar to my short path distillation, I don’t usually have issues with it.