Rate My Column

[shadylane]

1. How long should this reflux coil be? I see super confusing threads with math formulas and it seems like it should be 10" or more but than I read where guys are using 8" coils with a 5kW heating element.
The longer the better, short coils work best for a dephleg but your winding a reflux coil.

2. How far above the horizontal takeoff should the coil be?
Close to the takeoff is better but anything within a couple inches is good enough.

3. How tightly should the reflux condenser fit inside the column? I have a 1.5" OD pipe I can use as a mandrel. I tested some scrap condenser tubing and it is possible to fit it inside the column (VERY TIGHT) but I CANNOT slide it thru the tri clamp ferrule. This is why I am asking how close to the takeoff arm should the coil be. If it can be above the ferrule, I can proceed with what I have.
It doesn't hurt to have the coil touching the tubing, if it does it will chill the walls and add to the knockdown power of the RC.

[Steelers_Stiller]

Thanks Shady!

Here's a shot of the column with the valve mocked up.

[Steelers_Stiller]

Not sure why the pic is rotated, or how to fix it?

[Saltbush Bill]

I've read countless posts here saying a thermometer is not needed and you can't run a still by temperature and threads explaining why you can't. I understand that. I feel temperature is still a valid reference, especially for someone new to all this.

Steelers, when people say that a thermometer is pointless it is usually in the context of it being used on a pot still, or on a pot with thumpers attached.
Personally I also find them unnecessary on a plated column. They are especially confusing to newbies when used on all of the still types mentioned so far.
There are a whole heap of reasons for that , that I wont go into here.
Those types of stills shouldn't be allowed to be sold off the shelf with thermometers attached imo.
As far as I'm concerned they are sold that way for the Bling factor in an attempt to increase sales.
This in turn means that , because all of the stills on line have
thermometers , we now have a world of newbies who think that you must have a thermometer to run a pot.

NOW HERE IS THE CATCH! ..........Below is the reason that a thermometer is useful on a reflux still.

The Temp shown can vary from still to still, thermometer to thermometer, it is not for a set temp but as an indicator of what is happening inside the still WHEN THAT TEMP CHANGES.
Watching for that temperature change can help you fine tune the power input to the boiler charge and the rate that you are removing product,
It helps you tell when tails are about to arrive or indeed if they have arrived.
I run a 3 inch Boka, it is the only still of the 5 that I own that has a thermometer.....on that particular still it comes in very useful......I wouldnt be without the thermometer on it.
The thermometer needs to be quite accurate, a rise or fall of .5 of a degree can tell you things.
mine works in a similar fashion to the way that SMF describes below......with some small differences.

Once vapor starts to rise up the column the temp will rise. After a while you'll notice that the temp stabilizes as the column stabilizes. Once you start slowly taking off foreshots you'll see the temp shift a little which is normal. Later the temp will remain the same throughout the entire run right up until tails hits. You know you're into tails once the temp rises a few 1/10th degrees F and stays ... and soon will continue rising.

[Steelers_Stiller]

Saltbush, thanks for that explanation. Quite useful for a beginner like myself.

I appreciate all the advice from the seasoned pros here!

[OtisT]

Welcome back Steeler. Regarding your reflux coil, you would be just fine with a single wound coil in a 2” column. As long as you are using cool water and you can get a gallon a minute through it (3.5 liters/minute) you should be fine up to 5500W. The challenge I see with using 1/4” tubing for higher power systems is ensuring you get enough flow. I recommend packing with salt when winding to minimize kinking. If you are using recirculated water, I would consider using 3/8” tubing for increased flow, and I’d still use a single wound coil.

I ran a similar system (2” VM, 5500W) for years and never had a want for more knockdown power. My coil was 1/4” OD copper tubing wound around a 1” pipe. It is 11” long, 26 winds, used about 11’ of copper tubing total. It takes a flow rate just below 4 liters per minute to knock down 5500W thought you should never need to run your 2” with that much power.

I don’t think it matters if it’s touching the walls or not. It mainly comes down to how much cold water you are pushing.

I’d make sure the bottom of the coil is at least an inch above the top of the takeoff.

[Yummyrum]

I agree with Otis .
A 2” column will generally be flooding much after 2kw .

So in reality 3kw is all it needs to be able to knock down .

Spaced coils like Otis showed are better than close wound coils IMO. More space means slower vapour speed for better dwell time ( contact time with cool surface) and also access to cool surfaces .

And yes , about an inch above the port is about as close as you’d want to go . No harm in higher .

[shadylane]

Just guessing.
Have a space between the turns that equals the tubing diameter.
In other words with 1/4" OD tubing have 1/4" spacing between the turns.

[Pure Old Possum Piss]

My goal is to build a modular column that can be used for stripping runs/potstill mode running with the top of the column capped and output coming thru a liebig or, remove the cap from the top, and insert a copper wound coil to introduce reflux.

The main 2 things I'm curious about are
#1- do you think the length above the Tee is too great?
#2- where would be the best location for a thermometer port? I was thing just below the Tee. I intend to solder in a 1/2" NPT copper female adapter into the column somewhere. I have a stainless thermometer with male threads. I've read countless posts here saying a thermometer is not needed and you can't run a still by temperature and threads explaining why you can't. I understand that. I feel temperature is still a valid reference, especially for someone new to all this. Plus, it would look cool. Copper porn is half the fun, right?

Any other insight you all have on this setup?

Best place for a thermometer is in the trash can.
It gives ZERO useful info during a run. No one used to use thermometers in stills until marketers realized they could make an extra $50 for a $3 cheap Chinese part that looks "cool" but serves no function.

[SW_Shiner]

Best place for a thermometer is in the trash can.
It gives ZERO useful info during a run. No one used to use thermometers in stills until marketers realized they could make an extra $50 for a $3 cheap Chinese part that looks "cool" but serves no function.

Thermometers are fine in a reflux still. So long as you know what to look for. A thermometer in a still serves many functions, again, as long as you know what the numbers mean.

[Saltbush Bill]

Best place for a thermometer is in the trash can.

That' might be true of pot stills and some other still types but a thermometer on a reflux still can give good and usefull information.
It is not the temp reading it's self that your watching.
Yes you can run a reflux without one, but it sure makes it easier if you do have one.
Just for the record what sort of reflux still do you run?

[Yummyrum]

Maybe one of those new fangled electronic things with an alarm set to go off if temp rises 0.1° might be useful . But ….

I used to use one in my reflux still . Now , I just switch back to small jars when I recon tails is a litre or so off and do a taste test in each jar change ….. roughly every 10-15 min . If it tastes good , I keep it . If it has the slightest hint of tails , I put it aside . Pretty much guarantee the next jar is switch off time .

[Pure Old Possum Piss]

Best place for a thermometer is in the trash can.

That' might be true of pot stills and some other still types but a thermometer on a reflux still can give good and usefull information.
It is not the temp reading it's self that your watching.
Yes you can run a reflux without one, but it sure makes it easier if you do have one.
Just for the record what sort of reflux still do you run?

I've got a couple of pot stills and a couple of reflux columns. The old timey pot still/thumpers work great for my rums and brandies. Then I've got a little 26 gallon 4" CM/VM that I can run bubble plated or packed, that has a boiler thermometer, a pre RC thermometer and post RC at the point of no return.
I know it's overkill but when I built it years ago I had never needed or used a thermometer and thought at the time they would come in handy. So far the only one that really gives any useful data if the pre RC if i detune it and run it as a pot. Let's me know when the show is about to start.
Then there's the bigger one, an 10", but we're not allowed to talk much about that per site rules.
But I gotta admit, they make an old timey pot look pretty cool!

SBB your right buddy. It's not just the temp you look at but the changes in temp and at where in the column the changes happen or the stabilization of temps.

[Steelers_Stiller]

Got the reflux condenser wound. Double helix, 10" of coils, 1/4" OD tubing, 1/4" spacing between coils.

[Pure Old Possum Piss]

20250408_212603.jpg
Got the refluc condenser wound. Double helix, 10" of coils, 1/4" OD tubing, 1/4" spacing between coils.

Nice work!

[fzbwfk9r]

Nice winding

I hope I can do even half as good!

[Steelers_Stiller]

Welcome back Steeler. Regarding your reflux coil, you would be just fine with a single wound coil in a 2” column. As long as you are using cool water and you can get a gallon a minute through it (3.5 liters/minute) you should be fine up to 5500W. The challenge I see with using 1/4” tubing for higher power systems is ensuring you get enough flow. I recommend packing with salt when winding to minimize kinking. If you are using recirculated water, I would consider using 3/8” tubing for increased flow, and I’d still use a single wound coil.

I ran a similar system (2” VM, 5500W) for years and never had a want for more knockdown power. My coil was 1/4” OD copper tubing wound around a 1” pipe. It is 11” long, 26 winds, used about 11’ of copper tubing total. It takes a flow rate just below 4 liters per minute to knock down 5500W thought you should never need to run your 2” with that much power.

I don’t think it matters if it’s touching the walls or not. It mainly comes down to how much cold water you are pushing.

I’d make sure the bottom of the coil is at least an inch above the top of the takeoff.

Thanks for the detailed response. Much appreciated.

[OtisT]

That’s a really nice looking wind. Consistent spacing and no kinks so the flow should be good. Did you wrap that by hand, winding around a stationary pipe, or does that pipe spin like a lathe? That coil jig (Pipe with the two standoffs) looks like it’s mounted to a lathe.

I made myself a machine similar to a lathe that makes single and double wound coils, a coil winding machine that spins the coil jig and I just guide the tubing in as it spins. I used a rope that I wound around the jig with the tubing, as a spacer to get a consistent gap between winds.

[Steelers_Stiller]

That’s a really nice looking wind. Consistent spacing and no kinks so the flow should be good. Did you wrap that by hand, winding around a stationary pipe, or does that pipe spin like a lathe? That coil jig (Pipe with the two standoffs) looks like it’s mounted to a lathe.

I made myself a machine similar to a lathe that makes single and double wound coils, a coil winding machine that spins the coil jig and I just guide the tubing in as it spins. I used a rope that I wound around the jig with the tubing, as a spacer to get a consistent gap between winds.

The mandrel is mounted in a lathe. I actually forgot i had a lathe! My neighbor was cleaning house and offered it to me for the price of carrying out of his basement. I was about to figure out some wood contraption to hold the mandrel when I had an " ah-ha" moment and remembered the lathe.

I got the lathe running and rigged up a foot pedal in hopes that I could turn on the lathe and have my hands free to work the copper. The lathe sins way too fast for that to work!

I spun the lathe by hand by inserting a long drift pin in the holes for the check key. So I hand winding, I hand turning it over.

I filled the tubing with salt and used a piece of CAT6 cable for spacing.

I didn't bother to pin the outer mandrel to the inner. I wrapped the inner mandrel with cardboard on either end to keep it centered inside the outer mandrel.

I ran into an issue trying to remove the outer mandrel. I should have cut the long slot in the mandrel wider to have some more clearance in there.

Next step is to clear the coil. Didn't try too hard but, not luck yet.

[OtisT]

A really easy way to clear the tubing of salt is to connect one end to a water spout. Turn the water on and at first it appears nothing is happening. No flow. Wait just a few minutes and it will clear right out.

[shadylane]

A really easy way to clear the tubing of salt is to connect one end to a water spout. Turn the water on and at first it appears nothing is happening. No flow. Wait just a few minutes and it will clear right out.

While I'm looking at the end of the tube wondering why nothing has happened yet.