Swan Neck Pot Still

[myles]

The cones are going to overalap and have riveted and soldered joints. You could build a curved swan neck in the same way with a series of graduated cones. Because each is a funnel you can also build in the curves that you want. Mime is very basic, just a ball topped with a cone - but you can get any sort of profile you like.

The lower section of each cone has tabs cut, just like a welsh seam - but these are flared out to meet the inside of the cone below to make the joints. Because I like to do so I am riveting each tab also. As the lower diameter on each come is bigger than the top diameter of the preceding cone it fits like a cork. This gives you the flexibility to change the angles to make the curves - if you wish. Put the cones together, rotate to the correct angle and then mark where the seam line will be so you can cut and trim the tabs. After that it is just a case of flaring the tabs out and soldering them.

I am building two halves which will then be joined at the mid point through the opening in the base. This was going to be a 6" triclamp but it is much heavier than I anticipated, so instead this is going to be a flange type joint that will be soldered as the last opperation in the build.



If you wished to build a multi profile swan neck you would start at the narrow end. That way each joint is being made with access through the wide opening of each cone - just solder them together one at a time with each cone probably only a few inches long

[Rum Bum]

Great idea! Though I think you mean to say still head, not swan neck. And once I get use to soldering I might start to use sheet myself, if I had the skills I would use all sheet top to bottom.


RB

[Rum Bum]

Myles, my apology, for a few years I've been under the (logical and sensible ) impression that the swan neck was the curvy tube between the still head and condenser. Though I was mistaken, the swan neck is the still dome part, that resembles anything but a swan.


RB

[myles]

??? I think you were correct first time. The dome / boil bowl etc is often called the 'still head', and the curvey bit IS the swans nrck.



Building a small diameter curve the way I tried to describe with graduated cones, could be quite difficult. However, I think it could be done for something like this:

[Rum Bum]

Gathering everything I've read and seen concerning swan neck's, it's defined as any conical section between the boiler and condenser. Therefor on you top picture, the head/dome/bubble bowl could be considered a swan neck ...and so could the lyne arm because that too is also cone shaped (by the fact that it begins with a wider diameter than it ends with).

On the third page (at the link below) an arrow points to the bend in the lyne arm, calling the entire thing a swan neck, which tells me that a swan neck does not have to be a straight cone, but could be one with turns, such as the lyne arm in your first picture Myles.

http://www.malt-whisky.eu/Daten_englisch/Pot_Still.pdf


RB

[myles]

Good info RB. I am sorry but I dont know how they make those multi curved small diameter tubes. I managed to put a curve into a 2" to 1" taper, but it was gentle and changed the tube to an oval profile. Previously I have thought that you might be able to create the shape by wrapping copper tape in an ovelapping spiral, but that would be a lot of seam.

I wonder if they bend a straight tube into the curves, and then expand it out to fit a mould? As a sort of compromise I suppose you could use parallel tubular curves, with tapered sections in between.

[Rum Bum]

I think, my previous assertion was only half correct. Everywhere else I look the lyne arm is not part of the swans neck...it's just the lyne arm, even if its curvy and/or conical. The pdf just makes it look like it is, by the unsure arrow.

Ppffeeew

Glad I finally straightened out all my wrong assumptions.

About how they make the wavy lyne arm: My best guess is the they take a straight tube and hammer in a cone to expand the inside, then bend it to make the waves.


RB

[myles]

Anyhow RB, to get back on track Do you still wish to have a curvey bit of tube between your boiler and condenser. If so have you decided how you are going to do it. It certainly would look nice.

I am not doing so, I am going for the easier build of a boil bowl / conical riser combination that is going to feed into a big friedrich condenser. My current plan is to put a valve on the bottom of the condenser so that I can either draw product OR divert vapour ( with the coolant switched off) into a thumper. I am trying to retain the choice of single run pot still or thumper with selection of two valves. One in the coolant supply and one in the vapour path.

Have you seen this one?



If you build the surface area into the still head then you don't need the complicated multi dimensional swan neck. The still above is a bit too geometric (for aesthetics in my view) but it reputedly wins awards on a regular basis. There is something special about a nice swans neck though, something to aspire towards perhaps

[Rum Bum]

The lyne arm that I'm planning on making doesn't seem that difficult, it's just soft 3/4" tubing with a few curves in it. I'm just going to use a tube bender and bend it until it looks right. It'll have about a 2-3 ft drop and 5-6 ft run, measuring from opposite points. But I'll decide when I have it in my hands. I have no background in metal work but I'm assuming that this is no big deal, right? Though I haven't seen anyone do it before, on the hobby scale. Only if this tubed changed diameters would I have a greater issue on my hands.

And yes I've seen pictures of some similar to the one above, looks like the Colonel built it. That's one heavy Freddy.. chained to the ceiling in 3 spots!

And Myles, I thought we had cleared the swans neck confusion thing up!


RB



P.S. Maybe I made my last post stating my conclusion a little wordy.

[Rum Bum]

I just got some of the copper pieces in the mail! Excited to start building!


RB

[skow69]

This is awesome. Hammered copper alembics give me wood.

RumBum--If you are not familiar with the process of annealing, you might want to check it out before you start bending that tubing.

Great pictures, both of you, keep 'em coming.

Hey, I know! Why not make a lyne arm that is just shaped like a swan's neck?

[skow69]

Myles--I love your plan. That's why it's such fun. Creative variations are unlimited. Have you considered the more traditional rectifier ball in lieu of the thumper. It could be easily bypassed with a valve as well.

"The dual Egrot alambics. The larger alambic at left has a capacity of
900l, the smaller one at right holds 200l. Both are jacketed with wood,
and topped by a traditionally shaped chapiteau, which leads via copper
pipe up to a rectifying ball above the condenser.

"The rectifying balls return some of the heavier vapours to the pot, while
the balance condenses in the cooling coils submerged in water in
the grey coloured tank below, before being collected in the horizontally
mounted cylindrical distillate tanks at the bottom."

[Thanks to oxygenee.com]

[skow69]

I guess "chapiteau" must be French for "cool shaped boil bowl."

[Rum Bum]

Sweet looking stills Skow, I like how they are suspended off the ground!

Here is a question for anyone with the proper knowledge, can I solder my two 2"x4" reducers alone, or do I need to insert a 4" pipe inside?



RB

[skow69]

You will need a short stub of 4" pipe. It is theoretically possible to make a butt joint between two parts of identical diameter, but in practice it will never seal properly. You need the contact area provided by the lap joint to make an acceptable bond. Remember soldering happens by capillary action.

[Rum Bum]

I could make the stub out of sheet copper right? Would 2" of it be enough?

Here is my updated design: If my lyne arm proves too difficult to make, I will make something simpler.


RB

[skow69]

I wouldn't go any shorter than 2", and be sure to center it between the adapters. Also, it needs to be pretty close to perfectly round and the correct diameter. If not, it will be impossible to make a reliable seal. [Think capillary.] But considering the price of large diameter tube, if you have the sheet why not give it a shot? If it doesn't work, you're not out much and you learned something.