Looking to make a Worm for a Barrel

[John S]

I am looking to make a 300 Gallon Pot Still and I'm wondering how big the Worm should be. I'm considering using 7/8" soft copper, coiled tubing to make the worm. However, anyone know how long a 7/8" wide worm must be for a 300 gallon still? Opinions?

Maybe I'm on the wrong track, and 2"-3" wide copper tubing is necessary, while 7/8" tubing is simply too small?

[ViolentBlue]

with 300 gallons you might be pushing the limits of a 7/8 coil.

it will work, but it will probably be the biggest point of resistance in your system.

the length of coil you need would really depend on a lot of things, your reservoir size (barrel), water exchange rate in the barrel, incoming water temperature and your intended output speed. it all comes down to a matter of physics. Best follow #1 rule of "seat of pants" engineering- More is better.

I would venture a guess you'll want minimum of 50'of worm and very fast flowing and very cold water. add more length for slower water or higher temperature water.

a 7/8 coil might be sufficient if you were to use a precondenser of some sort before your vapor entered the 7/8 coil. the purpose of the precondenser is not to liquefy all vapor coming through, but to knock it down to a level that the coil can manage. a shotgun style could be built compact enough to fit the bill, you wouldn't need a long section, maybe 16-24" before feeding the Worm.

[Seattle Spirits]

How many Watts are you putting into the still, that actually matters more then the batch size.

Also are you doing to do a counter flow or do you want to use a traditional worm in a barrel?

What would your cooling water's temperature be?

Basically you need to remove as many BTU as you put in, I know there are losses other places but it is a good ball park number.

[bluestar]

I am looking to make a 300 Gallon Pot Still and I'm wondering how big the Worm should be. I'm considering using 7/8" soft copper, coiled tubing to make the worm. However, anyone know how long a 7/8" wide worm must be for a 300 gallon still? Opinions?

Maybe I'm on the wrong track, and 2"-3" wide copper tubing is necessary, while 7/8" tubing is simply too small?

Where are you located? What flow rate are you anticipating? You might be able to use two 7/8" tubes in parallel in the same barrel. That could be far cheaper than running larger tubing.

[Chip Tate]

Where are you located? What flow rate are you anticipating? You might be able to use two 7/8" tubes in parallel in the same barrel. That could be far cheaper than running larger tubing.

You're right that you need to start larger on the diameter right off the still, but you can reduce the diameter the further down the worm you go. More is better and I would only try this if you're running pretty slow and have lots of nice cold water available. Otherwise, just make a shell and tube condenser--much better efficiency.

CT

[PeteB]

As Seattle Spirit said, heat input must approximately equal heat extracted by your worm. The volume of the still is not the main consideration.

I suggest you email ADI member Joe Pawelski who has offered to help members with heat transfer calculations.

In the mean time, it sounds as if you have access to 7/8 tube. One coil will probably have too much friction loss and your still will build up pressure.

Suggest you come off the still with a short length of say 2 inch tube then join, I guestimate 4 of 7/8 worms for the first few feet. A couple of "T" fittings would drop 4 to 2 worms then eventually 2 to 1 worm to come out the bottom of the barrel. Joe will probably suggest the lengths of coil needed.

If in practice you still get some steam out the end, make up a short length of shell and tube condenser to fit on the end. A short shell is how I fixed the steam from my still when I increased the heat input.

[Jonathan Forester]

You might want to get a goddard condenser from Jesse at Trident Welding. he packs 165 feet of tubing into a five foot condenser.

I am looking to make a 300 Gallon Pot Still and I'm wondering how big the Worm should be. I'm considering using 7/8" soft copper, coiled tubing to make the worm. However, anyone know how long a 7/8" wide worm must be for a 300 gallon still? Opinions?

Maybe I'm on the wrong track, and 2"-3" wide copper tubing is necessary, while 7/8" tubing is simply too small?

[John S]

Thanks a ton for your help guys. I'm now considering 1 1/2" soft copper, so that I don't push the limitation of the tubing. I like the idea of running two coils off the lyne arm, one inside the other. A total of 200' of 1 1/2" tubing should be a good start. Also, I plan on using a big 200-300 gallon tank to conserve water. What do you think?

Hey Jonathan,

That's a nice idea too, but I'm looking to build because money is tight. But I really admire the work that they do, beautiful stuff.