Bokakob build

[dunluce]

Hi all, first build here. Got my condenser done yesterday, and working on the plates today for a 2" column (man.....ugly work, but great learning experience).

Two questions while I am working on this.....does the output need to be 1/4 or could it be larger like 1/2"?

Secondly.....do you NEED to have a needle valve on this type of still? I'm planning to build two of them, and was thinking of maybe putting a union in to swap a 3/4, 1/2" liebig condenser between them, and use that for the output on the Bokakob.

Thoughts?

(Thanks in advance)

[Saltbush Bill]

and working on the plates today for a 2" column

Not sure how to answer this .......the thread is titled "Bokakob build" ............Boka's dont have plates ...they are packed columns which use copper mesh, volcanic rock or other products in the column.
Until I know what your you are really building it kinda hard to answer the question.


If you are building A boka the answer is yes.
Boka is a LM still "Liquid Management"
You need very fine control over the amount of spirit leaving the still at any given time......hence the need for a needle valve.
Trying to do it any other way is almost impossible. Hunting around the internet will turn up some reasonably cheap needle valves. From memory there is also a tutorial somewhere on this forum showing how to make your own needle valve for very little cost.

[dunluce]

Aren't there two slant plates at 30 degrees in a boka column? If not, what in the &*$% am I building?

[NZChris]

Yes, there are.

[MtRainier]

What is the leibig for on the boka still? I thought the point was that only liquid comes out of a boka?

[dunluce]

What is the leibig for on the boka still? I thought the point was that only liquid comes out of a boka?

I've read you can add one to cool off the liquid once it comes out of the outlet. Seeing as I will have a liebig for my other still, and modular in design, I was thinking of increasing the size of the boka outlet to 1/2", and using a union to add the liebig to it if I wanted to.

[Yummyrum]

What is the leibig for on the boka still? I thought the point was that only liquid comes out of a boka?

Some folk like to measure ABV during the run . So cooling Liquor down to 20°C makes measurement more accurate without need to do temp correction.

A 2” reflux Boka won’t be normally making more than 1litre/ hour ( when running in reflux mode) and as its already condensed , you don’t need a big heat exchanger to do it

[dunluce]

A 2” reflux Boka won’t be normally making more than 1litre/ hour ( when running in reflux mode) and as its already condensed , you don’t need a big heat exchanger to do it

Looks like I will probably be making a 3ft 1/2" inside of 3/4 liebig for a steamer build, so it would definitely be overkill.

[zed255]

Ain't no kill like overkill! Seriously though, if you have the space then using the liebig condenser as a product cooler is just fine. Plumb your inlet water to the spout end and run the water out to the input of your RC. The flow rate your RC will require will give you distillate out at about the temp of your cooling water.

[dunluce]

Ain't no kill like overkill! Seriously though, if you have the space then using the liebig condenser as a product cooler is just fine. Plumb your inlet water to the spout end and run the water out to the input of your RC. The flow rate your RC will require will give you distillate out at about the temp of your cooling water.

Thanks, So just to make sure this is correct.....water runs into the bottom of the liebig, out the top of it.....into the input of the column condenser and then out to wherever I am piping it - so the flow is moving against the spirit flow?

[zed255]

Yes, in most cases 'counter flow' is desired. Doing so helps avoid any shock cooling. Put the coldest part farthest away from approaching vapour.

[Saltbush Bill]

Aren't there two slant plates at 30 degrees in a boka column? If not, what in the &*$% am I building?

Ok....my mistake had you said slant plates I would have known ....as was I was imagining perforated plates or something
A small liebig or similar on a Boka is a good idea to cool the output.....but not 100% necessary

[dunluce]

Ok....my mistake had you said slant plates I would have known ....as was I was imagining perforated plates or something
A small liebig or similar on a Boka is a good idea to cool the output.....but not 100% necessary

Ha ha ha...no worries, you have me worried for a minute. I figured it out later when I figured out you probably were thinking of bubble plates or something like that. Thanks!

[dunluce]

Well, I decided to go the simple route and do a 1/4" output, but thanks all for the help. She's not pretty (first time I have ever soldered copper, so it's pretty ugly but I enjoyed doing it).

Thanks all for the help. It's great to be getting started.

[Yummyrum]

Well done duni .
Happy stilln

[still_stirrin]

Make sure you have an "adequately sized" vent hole in that top cap on the reflux condenser. You don't want it to "whistle" on you, or cause pressure build up in the column (and boiler).

I'm curious, did you calculate, or measure the liquid capacity of the "liquid cup"? The sharp angle for the slant plates suggests it might hold a couple of ounces, or 200+ ml. It's not a problem, but it will cause the "cut line points" to be a little more "fuzzy", that is, with a little more smearing. Still, a LM still is really good for compressing the heads, so it should run OK for you (as your first still).

One thing...the Bokakob is a slow operating still. So, be patient with it.

Be safe, responsible, and discrete.
ss

[dunluce]

Make sure you have an "adequately sized" vent hole in that top cap on the reflux condenser. You don't want it to "whistle" on you, or cause pressure build up in the column (and boiler).

I drilled a couple of extra 1/4 holes on top of the ones for the condenser coils. Never thought about whistling...don't think it will be an issue but if it is, it's removeable if it needs modified. I used to teach music....maybe I can just modify it to a train whistle note to annoy the wife. lol

I'm curious, did you calculate, or measure the liquid capacity of the "liquid cup"? The sharp angle for the slant plates suggests it might hold a couple of ounces, or 200+ ml. It's not a problem, but it will cause the "cut line points" to be a little more "fuzzy", that is, with a little more smearing. Still, a LM still is really good for compressing the heads, so it should run OK for you (as your first still).

Nope, just eyeballed everything. Honestly didn't expect it to actually work out, so I was more or less experimenting to learn how to do it. And yes, it's the first still....already have plans for a steamer build.

One thing...the Bokakob is a slow operating still. So, be patient with it.

Be safe, responsible, and discrete.
ss

Slow is fine to learn with....don't like trying to learn faster than I can react to things.

Thanks guys.

[dunluce]

Steam/vinegar runs seems fine, no apparent leaks I can find. Thanks again for all the help guys.

[dunluce]

I have a question for the condenser coil....1/4" copper, 400gph pump. Should it be knocking down all the vapour?

I have two 1/4" holes in the cap beside where the condenser tubes come out, and putting a mirror above it, there are "puffs" of vapour coming out of the top.

[NZChris]

How many watts are you using?

[dunluce]

How many watts are you using?

Unfortunately, using a Brewzilla with a distillation top until I get my keg boiler built.

Edit: I did have both the 1000W and 500W burners on.

[NZChris]

Mine is 1/4" OG and knocks everything down when I want it to. The top is open and I have a spare thermometer reading the temperature at the very top in case something goes wrong.

[NZChris]

Deleted, double post.

[Yummyrum]

Do you have a pic of your coil?
Is it single or double layer ?
Is there spaces between coils or close wound ?
How long is it ?
Are there pinched bits that might restrict flow ?

As fir the pump , what head of pressure can it run at ?
Some pumps can move a lot of water but are useless at lifting it up hill .

Having said that , a “typical “ dual layer 1/4” coil about 8” long should have no worries knocking down 1500w

[zed255]

I can get a mist out my vent hole on my RC, especially running hard or towards the end of the run. I can actually hear a rumbling sound from the vapour collapsing.

I am pretty sure it is just an oscillation of vapour and outside air rushing in and out of the RC. If I lift the RC out of the shell tube a little to make a very large vent the effect stops. In configurations where my RC needs to be fully seated I just set a marble on top of my 1/2" vent; any pressure build up will easily pass the marble but it acts as a one-way valve and keeps the mist inside. Otherwise, in CCVM mode the coil is lifted part way and there is no issue.

I found I could reduce the misting with better control over water flow. Slower water gives warmer water out and more of a gradient over the coil which helps. Also, like a Liebig you get better performance if the water is counter flowing.

https://homedistiller.org/forum/viewtop ... 87&t=67439

[dunluce]

Mine is 1/4" OG and knocks everything down when I want it to. The top is open and I have a spare thermometer reading the temperature at the very top in case something goes wrong.

Thanks Chris. I do have a thermometer above the bottom plate, and I did notice that the column stayed very cool, but when it finally started reading 173, it seemed to shoot up above that very quickly. My worry is that flammable vapour will be escaping, a fire hazard.

Do you have a pic of your coil?
Is it single or double layer ?
Is there spaces between coils or close wound ?
How long is it ?
Are there pinched bits that might restrict flow ?

As fir the pump , what head of pressure can it run at ?
Some pumps can move a lot of water but are useless at lifting it up hill .

Having said that , a “typical “ dual layer 1/4” coil about 8” long should have no worries knocking down 1500w

Definitely could be some parts that are narrowed, but not actually pinched...could be restricting some flow. First coil I have made that actually worked out. As for the pump, not sure what the head pressure is. Might need something stronger, as it does seem to have to a bit of issue getting water up to the top of the column, but then it is a steady full flow out the end of the tube.

I can get a mist out my vent hole on my RC, especially running hard or towards the end of the run. I can actually hear a rumbling sound from the vapour collapsing.

I am pretty sure it is just an oscillation of vapour and outside air rushing in and out of the RC. If I lift the RC out of the shell tube a little to make a very large vent the effect stops. In configurations where my RC needs to be fully seated I just set a marble on top of my 1/2" vent; any pressure build up will easily pass the marble but it acts as a one-way valve and keeps the mist inside. Otherwise, in CCVM mode the coil is lifted part way and there is no issue.

I found I could reduce the misting with better control over water flow. Slower water gives warmer water out and more of a gradient over the coil which helps. Also, like a Liebig you get better performance if the water is counter flowing.

https://homedistiller.org/forum/viewtop ... 87&t=67439

That makes sense. As I stated above my concern is that flammable vapour might be escaping, and as I have very little to no sense of smell, I wouldn't be aware of that. Wouldn't want to check the column top with a lighter.

[dunluce]

Do anyone have a link to a good pump they are using, for a 1/4 condenser coil, maybe on Amazon? I'd like to see what people are using....I'm not really sure what I am looking for, and this one that I have can always go into the cichlid tank.

Also, how many gph can you actually push through a 1/4 condenser coil?

Thanks for all the help so far.

[dunluce]

Advice on this one possibly? Doing some looking online and my pump I have is obviously too small.

[Yummyrum]

It says it can pump to 13’ bit thats when it stops flowing . Even at 6’ ( about the height of a boka ) , it won’t have much flow .

I know they are a bit more expensive but sump pumps / butt pump / submersible pump are excellent . A 300w one should work fine .

https://www.bunnings.com.au/ozito-350w- ... lsrc=aw.ds

Many of us use this sort of pump .

[dunluce]

It says it can pump to 13’ bit thats when it stops flowing . Even at 6’ ( about the height of a boka ) , it won’t have much flow .

I know they are a bit more expensive but sump pumps / butt pump / submersible pump are excellent . A 300w one should work fine .

https://www.bunnings.com.au/ozito-350w- ... lsrc=aw.ds

Many of us use this sort of pump .

Your link didn't work for my, just brought me to the main page, and a search doesn't bring up that pump. Found it in Google search though.
So thanks, I will do a search and see what I can find with matching specs up here in Canuckistan. Seems on Amazon (confined to the house for a while here) only rates low power pumps in watts, but high power in horsepower. So I'll look for maybe a 1/3 hp pump then with other matching specs.

Thanks again.