Customer Review of the Better Flange SPD

Hey everybody! Been wanting to make a post for a while but have finally gotten around to it.

So full disclosure, this is my honest review. I was not compensated for my thoughts on the unit. I’m just a really big fan! :slight_smile:

So after receiving the unit I was super impressed with the build quality and craftsmanship of the custom components. The stainless parts were super well made with nice beads. The glass components were thick and had a perfect seal with both the kf gaskets as well as the ground glass connection for the thermowell. Very happy with the build quality.

After assembling the unit, and playing with different configurations we settled on the one pictured below. Still need to tweak a few things and definitely get some support for the head so that flask changes are easier. I elected to implement a ball valve in the condensation pathway and a ball valve at the cold trap so that I could perform flask changes the way that we used to do them with our USALABS 5L. Using this setup we are able to isolate the RF and release vac. Flask changes are super quick IF you have the head adequately supported (we did not. will fix for next run.)

Setup and teardown of the unit couldn’t be easier and cleaning is such a breeze. We used to spend an hour or so cleaning the old setup but now we have it clean in 30 or less. It is nice to be able to clean it up and pre-assemble the parts so that I’m only putting a few clamps together and the whole thing is built.

Using 1 Alcatel 2021i I was able to get to as low as ~45micron with an empty and dry setup. I didn’t have to chase my tail finding vac leaks. I kicked my pump on and watched it fall very quickly until we settled down to mid 40s. I even left it under vac with the pump off over night and it only rose to ~2500 micron in 24hrs.

The performance of the unit was what blew my mind the most. I can confirm that after the head heats up and the system is up to temperature, we were achieving 1L/hr throughput. For a 2.2L batch size, it took 2hr30 from the time that we hit distillation temps at 180 in the flask. The important part to note is that the head has to be up to temperature before it starts to distill. It took ~35min to get to that point. From that point onward it went screaming fast at a 1L/hr rate. I cannot wait to run larger batches through this unit.

For comparison our usalab 5L rig was running about 250mL/hr using the same 5L mantle and BOTH vac pumps (always chasing down leaks). We also got to eliminate our sous vide and mag pump as the condenser is ambiently cooled. 2 outlets freed up with 4x the performance gains using half the vacuum power!! Cleaning time is ~1/3 the time vs our glass unit with pretty much zero chance of damaging when it inevitably hits the concrete.

All in all, I’m just going to go out and say that @AlexSiegel knocked the Better Flange SPD out of the park, and I couldn’t be happier with my purchase. I am never looking back to glass SPDs. I can’t wait to play with alternate configurations and really tweak this thing. If anyone has any suggestions or questions, I am all ears.


Flip ur vac sensor, so that the sensor is sitting above the channel. I think solvent or disty could get trapped in there and give u some bad readings during operation.

Thanks for the review, ive been eyeing this for awhile but unfortunately the budget doesnt allow for me to get it.
Might have to “accidently” break another glass piece to convince the crew its a needed upgrade.

Since ur limiting factor is the head on start up, maybe wrap a heating line around the head just for start up, to get it up to temp faster.

What i like most about this setup is that its not all one connected angle from the head and the head isnt dealing with alot of stress from the angle being alittle off or ur clamp slipping on the cold trap.
I like how the coldtrap can just be left on its own stand and just disconnected and connected again. Fitting 24/40 or any glass joints together at the same angle can be tricky with some setups, this eliminates that issue.

One upgrade i would make is putting a Y adapter after the reciveing flask and b4 the cold trap. Setup a second cold trap and have two lines of vacuum. One cold trap (a) just has dry ice and solvent and the other (b) has liquid nitrogen. Use CT (a) for ur roughing pump and start up, then once ur in mains switch over to the CT (b) and use a better vac pump. That way all the “mess” is contained to one side, then once the system is past volatiles, u can switch to the CT (b) to have virtually no volatiles refluxing in ur cold trap during a run


Nice eye. It was only after I posted it that I realized that I used an older picture. That pic doesn’t even show the ball valve on the cold trap. I’ll throw another one up when we do our next run and actually have the head properly supported.

We were talking about adding a heat tape or insulation to the head to speed it up, and we may do it, but I don’t think it’s really all that needed. If it ends up taking longer in the winter to get up to temp, I’ll probably implement it, but it gives us time to get other stuff done/cleaned before we start distilling and need to change flasks so right now I’m just gonna leave well enough alone and dial in the other areas. I’m sure there are several ways to wring out efficiency for those inclined.

I really like your idea for the clean and dirty side cold traps. I’ll definitely keep it in mind. Originally we planned to keep both vacs set up and then load balance by doing 1 run on one pump and then the next run on the other pump. Or run one till it’s clapped out and then grab the other from the shelf and swap it in. Either way, the modularity of the system is endless and I look forward to seeing what other people come up with!


I run a big glass head that takes forever to heat up, i just put it and the flask in the oven and pre warm it. Then assemble and its good to go, no popping or spitting from running vac waiting for it tow warm up


That’s an awesome and easy solution to the head warming issue. If I wanted to wring the last bits of efficiency out, I’d totally do it. My problem is that indofab etched “CAUTION: HOT DO NOT TOUCH!!” (Yes 2 exclamation points). Ask me how many times I cooked my index finger “feeling” where the heat front was at while the warming process was underway. My temp gun was off bc stainless and the only way to figure out where the heat front was at during distillation was to feel it. That being said, FUCK putting together a nuclear hot rig. I’ll eat the 30min just to not nuke myself.

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I do it to 150f thats it, standard rubber coated work gloves make it no problem. This head takes way longer to heat up, it screams when its set though.