Bokakob 2" under construction.

[moodie007]

Thought id do a progress report on my first still. Making a 2" Bokakob and thought id start off with the coil/condenser. First time working with copper so im sure it will be a bit of a challenge.

Condenser is 300mm long using 5m of 1/4" copper. Used the 16mm and 32mm pipe method to form. Heated end as you can see to soften copper to make it easier to shape the inlet and outlet tubes but the rest was just wrapped around the tubes unfilled and un-heated.

If you can see any mistakes, or if you have any suggestions feel free.



More updates to come.

[Austin Nichols]

Hey dude it looks ok and should work fine, good luck with the rest of the build.

Cheers.

[moodie007]

Hey dude it looks ok and should work fine, good luck with the rest of the build.

Cheers.

Cheers. I was thinking the air gaps may have been too big or inconsistent so was think about trying to make another one but if we are sure it will work fine i might leave it for now.

[Samohon]

Hey dude it looks ok and should work fine, good luck with the rest of the build.

Cheers.

Cheers. I was thinking the air gaps may have been too big or inconsistent so was think about trying to make another one but if we are sure it will work fine i might leave it for now.

That coil looks good moodie007, IMO it dont matter how it looks, as long as it works...

Keep us posted with the rest of the build...

[moodie007]

Im located in Dunedin NZ and thought Id provide a list of parts, cost and where we got the parts from. May not be the cheapest. If you know if parts and or local suppliers that are cheaper let us know.

Parts obtained so far and where i got them from:

6m of ¼” copper pipe GasCo $25
1/4" inline brass needle valve with male and female connectors to the copper. HDT Flow Tech $47
2” copper end cap Edward Gibbon Ltd $11
2" brass threaded adapter male Edward Gibbon Ltd $40
2" brass threaded adapter female Edward Gibbon Ltd $50
2m 2” copper pipe GasCo $120
Solid Core Solder & 100ml Flux HDT Flow Tech $19
1/4 " brass Elbows and hose connectors for the water in and out HDT Flow Tech $17
Keg (not obtained yet)
Pot Scrubbers (not obtained yet)

Turns out Edward Gibbon could have supplied the 1/4" and 2" pipe as well but GasCo have been very helpful. Edward Gibbon did tell me the 2" from GasCo was a very good price.

16mm & 32mm steel rods for making the condenser were offcuts obtained from a local office chair manufacture. $3

Total cost for parts $332NZ

[hoody]

2" copper male and female threaded adaptor's??!

I was under the impression these were un-obtainable in NZ??

Hoody

[moodie007]

Nup they were the easiest to find, well i stumbled across the solution straight away. The female is something else but works perfectly. Attached some images i just took with cell phone.

[hoody]

Look like brass to me. If so might pay to do a bit of reading on using brass in a still. Some are of the opinion it is ok (with "pickleing"), while other's say it is a no no.

If they are copper, let me know were you found them, I want some!

hoody

[moodie007]

Sorry, yes you are right they are brass.

From what I understood the only issues with brass was lead. To meet NZ standards brass for plumbing in NZ has to be lead free apparently. There is some standard that they have to adhere to.

[hoody]

interesting? I'll have to do some more reading!
You were lucky to get short length's of pipe too, most places will only sell it at a minimum 5m length.

hoody

[moodie007]

interesting? I'll have to do some more reading!
You were lucky to get short length's of pipe too, most places will only sell it at a minimum 5m length.

hoody

Yeah that was the difficult bit, thats why I went to companies that use large amounts of copper to buy offcuts off of them. GasCo install heaters etc.

[moodie007]

Sorry, yes you are right they are brass.

From what I understood the only issues with brass was lead. To meet NZ standards brass for plumbing in NZ has to be lead free apparently. There is some standard that they have to adhere to.

Apparently there is a lead test kit you can get from hardware stores. Ill see if i can get one of those kits and test them.

Ill let you know the results.

[moodie007]

I've worked out what we can do to make these brass adapters safe. Im going to take them to an engineering shop with a 24 pack of Speights and ask them to throw the adapters in the mill to have the centers honed right out to 50mm all the way through. Then ill make sure that both sections of the 2" copper butt up nicely to each other then there is no brass in the vapour path.

Easy.

[moodie007]

Ok my brass fittings had Spartan DR stamped on them. Spartan is the NZ manufacture of these parts. Contacted Spartan and Spoke with a friendly chap Wayne who has been in the industry for over 20 years.

According to Wayne, There is no such thing as lead-free brass. They have lowered the amount of lead in the brass but it is still required. Fittings stamped with DR or DZR are dezincification resistant.

From Wiki http://en.wikipedia.org/wiki/Brass : "The so called dezincification resistant (DZR) brasses are used where there is a large corrosion risk and where normal brasses do not meet the standards. Applications with high water temperatures, chlorides present or deviating water qualities (soft water) play a role. DZR-brass is excellent in water boiler systems. This brass alloy must be produced with great care, with special attention placed on a balanced composition and proper production temperatures and parameters to avoid long-term failures."

So this brass is designed to be corrosion resistant but will still contain lead and arsenic at low levels.

So on that note, I’ll be getting the bushes machined so the copper from the condenser and column meet (therefore no brass will be in the vapour flow), and I’ll be disassembling the needle valve and pickling.

Thanks for the heads up Hoody

[hoody]

No worries. And good to see you investigated the problem, and found a solution!
Nice work and let us know how you get on (with pic's! )

Hoody

[moodie007]

Finished putting the condenser togeather. Didnt have the in and out pipe long enough for the crimp things to work so soldered the brass lug to the copper. Messy i know, but first time ive worked with metal. Tested it and it didnt leak and the coil felt quite cold so looks like it will do the trick.

Sorry about the pic quality, just using my cell phone, but you get the idea.

[moodie007]

Working on the plates now. Have made up plates and cut the top slot in the 2" pipe. Only question is, how far apart should the two plates be. There dosn't seem to be an exact guide. Some people are using more than the 1/4" as specified on the template. I was considering 19mm. Anyone know of an ideal distance?

The heavy black line is where i have cut already. The line at the end of the rule is is the line im considering cutting along for the bottom plate.

[moodie007]

Put it together anyway with the plates 20mm apart. Hopefully it's right and will perform well. Just need to find a keg and fit it to it and ill be all go for testing.


My soldering is pretty bad and i still need to clean it all up but does it look about right?

[Ayay]

Hey Moodie, that's lookin good! Any boiler will do provided it's stainless or copper and it's more than 25L.

A little brass is not too bad if it's had the lead removal treatment.

[moodie007]

Cheers. I do have my essencia 25l boiler but I think ill try and get a 50. I would have to make the hole in the lid bigger and the old CM head would no longer fit with out modification. So im off to the local breweries tomorrow to see if I can scav a keg or two

[moodie007]

A little brass is not too bad if it's had the lead removal treatment.

Yeah the only part that is exposed to brass is the needle valve that will be treated before use.

[Ayay]

Good luck! 50L Is the sweet spot because it will run a 40L charge in one long day depending on how you are running it

[hoody]

Nice work moodie!
As far as the plate spacing goes, I think your's will be fine. I looked at alot of other people's out there and took a bit of a average and spaced mine 3/4" apart. I know of other's using a 1" space with no drama.

Hoody

[Pooyan]

Looking good Moodie!, and your soldering is better than mine
That 20mm spacing between the slant plates will do just fine.
Are you planning to make the Boka-head detachable from the main column? (for easier cleaning and stripping runs)
From what material is the thermoprobe casing made off?

keep us updated on the build and let us know how she runs....hmmm, in fact, we all know the outcome of the latter

edit: spacing size

[moodie007]

Nice work moodie!
As far as the plate spacing goes, I think your's will be fine. I looked at alot of other people's out there and took a bit of a average and spaced mine 3/4" apart. I know of other's using a 1" space with no drama.

Hoody

Yeah i figured the same in the end hence the 20mm (3/4")

Thanks for the feedback Cant wait to get this fella running

[moodie007]

Looking good Moodie!, and your soldering is better than mine

Have to admit I had to get the grinder out LOL

Are you planning to make the Boka-head detachable from the main column? (for easier cleaning and stripping runs)

Yes i have got a couple of brass couplings that i have had machined out to 54mm. The fittings slide right over the copper. The head and column copper will butt up to each other and no brass will be in the vapor path.

From what material is the thermoprobe casing made off?

what you can see is a rubber bung insulating and sealing the probe from the copper. The bung and probe came from a local brew shop. The probe is stainless.

keep us updated on the build and let us know how she runs....hmmm, in fact, we all know the outcome of the latter

Certainly will

[rad14701]

The only difference that the air gap between the two slant plates makes is the amount of vapor speed increase that will be realized in that area... For example, with a .75" air gap you will not increase the vapor speed...

How did I establish this rationale...??? A 2" diameter column has an area of 3.14 square inches... A horizontal window 2" wide by .75" high has an area of 1.5 square inches... Roughly half that of the column, for a vapor increase of ~2x... Double the height from .75" to 1.5" and you are at 3 square inches, or virtually zero vapor speed increase... But wait...

Of course there is still a minor deviation from these figures as the vapor first heads around the plate, but these figures get use close enough for government work... I'd consider .75" to 1" to be about optimal for our needs as it's probably not worth getting into more complex geometric calculations given what little added benefit there would be to gain from such an exercise, but here goes, minus the equations which were done in my head...

When we consider that the plates cover roughly 1/2 the column area the figure of .75" is pretty much right on the money for a 2" column and 1" air gap would be good for a 3" column... With air gaps of these sizes the vapor speed will essentially remain the same from the time it hits the bottom plate until it passes above the top plate... There is no way to get around the 2x vapor speed increase due to the plate covering half of the column, but we can keep that speed increase at 2x instead of increasing it further...

Perhaps not the best place for this explanation, but here is is just the same...

[Kentucky shinner]

Looks to me like you have done a good job.. You I think will be very happy with your bok.. It makes some really good likker.
KS

[moodie007]

The only difference that the air gap between the two slant plates makes is the amount of vapor speed increase that will be realized in that area... For example, with a .75" air gap you will not increase the vapor speed...

How did I establish this rationale...??? A 2" diameter column has an area of 3.14 square inches... A horizontal window 2" wide by .75" high has an area of 1.5 square inches... Roughly half that of the column, for a vapor increase of ~2x... Double the height from .75" to 1.5" and you are at 3 square inches, or virtually zero vapor speed increase... But wait...

Of course there is still a minor deviation from these figures as the vapor first heads around the plate, but these figures get use close enough for government work... I'd consider .75" to 1" to be about optimal for our needs as it's probably not worth getting into more complex geometric calculations given what little added benefit there would be to gain from such an exercise, but here goes, minus the equations which were done in my head...

When we consider that the plates cover roughly 1/2 the column area the figure of .75" is pretty much right on the money for a 2" column and 1" air gap would be good for a 3" column... With air gaps of these sizes the vapor speed will essentially remain the same from the time it hits the bottom plate until it passes above the top plate... There is no way to get around the 2x vapor speed increase due to the plate covering half of the column, but we can keep that speed increase at 2x instead of increasing it further...

Perhaps not the best place for this explanation, but here is is just the same...

So what your saying is 19mm is all good LOL

Ive got a lot to learn I can see

[moodie007]

Added a Liebig to cool the product. I know its probably a bit long. If so ive made it in such away that the end cap easily can be unsoldered and slid off and the external tube shortened.

Excuse the mess on the bench LOL