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2" Boka Build

PostPosted: Mon Jul 10, 2017 10:37 am
by Hazardcone
After much encouragement from forum members on my intro post, I'm going to share my experiences building a Boka. Please note I'm a rank amateur but my post may help others who are contemplating a build but don't know where to start. I was certainly scratching my head a lot working out what to buy and where to source it.

Here are a sample of the many sites I visited.

http://learntomoonshine.com/how-to-buil ... structions
http://wiki.homedistiller.org/index.php ... w_To_Build


From my research I understood that a 2" Boka can produce twice as much product as a 1.5". I also soon found out that 2" in OZ is actually 50mm in a plumbing shop....sizes differ and Bunnings is bloody useless unless you want 1/2" or 3/4". :-| The optimum size of a packed column is between 120mm and 150mm. Copper packing is best but stainless steel scrubbers are good too, easy to buy and cheap. So I went stainless.

I bought a 2m length of 50mm copper from Samios here in Adelaide. Cost a little over $100. As soon as I had it in the car I found myself looking at it and touching it....there is something about copper :romance-kisscheek:

The first decision to make is how far down the plates need to be. This is dependent on how big your coil is. The top plate should be about 25mm below the bottom of the coil. Making the coil was the thing that worried me the most. My research showed all sorts of disaster stories and really ingenious ways of making the coil by filling it with salt (sometimes difficult to get out afterwards) or coil winding machines that just looked like a whole new hobby. To start with I bought some annealed 1/4 pipe. Bought from ebay http://www.ebay.com.au/itm/162038944411 ... .S1.R1.TR3 Aussie seller, fast service...very happy :handgestures-thumbupleft:

Re: 2" Boka Build

PostPosted: Mon Jul 10, 2017 5:34 pm
by Hazardcone
I had to make the coil. After all the reading I had done and the horror stories I had read I figured "just do it and see what happens". I think I might have had a couple by this time. 8-} I had a piece of steel tube of small enough diameter to use as a former. I taped one end of the copper to it and started to twist the tube with my hand and bend copper around it using my belly. Hope that makes sense. It was working! The tube was a little flattened but was in pretty good shape. :smile: It was pretty hard work on the hands and the belly though. After I finished the inner coil I was feeling pretty happy with myself so I pushed a piece of 30mm conduit over the inner coil and started to form the outer coil. Then it happened! Twice! :shock: I had two kinks in the tube where I had tried to bend it back on itself. Bloody hell!

So I did what most self respecting craftsman would do...I ignored it and carried on. Wound the outer coil using the same method. Went on a bit easier as the diameter is bigger. When I had finished I cut off the excess copper and tried to blow air down the coil. It was OK but a bit of pressure needed. I'll leave it. :shifty:

I decided to measure the length of it inside the pipe so I would know where to cut the first plate. It didn't fit! It was too big! :scared-eek: So I took it in both hands and started to twist it to make it smaller. It worked...looks like shit but it now fits inside the 50mm tube. I had read that you need about 3m of copper to form the coil. When I looked I had used about 5m. I hooked up the coil to a garden hose...pretty good flow through it. :happy-partydance:

I cut three holes in th head cap. Two for the coil ends and one to let out any pressure build up. Coil done!

Re: 2" Boka Build

PostPosted: Mon Jul 10, 2017 6:51 pm
by Fishleg
Looks good :handgestures-thumbupleft: :handgestures-thumbupleft: :handgestures-thumbupleft:

Re: 2" Boka Build

PostPosted: Mon Jul 10, 2017 9:10 pm
by Thiele
I am about to make a condensation coil very similar to your coil.
Did you end up using salt as a filler for copper tube during bending?

How difficult was it to get the salt out?

(I also know someone who used fine sand, which worked very well during the tube bending but there was lots of hassle getting the sand out of the tube)

Re: 2" Boka Build

PostPosted: Mon Jul 10, 2017 9:19 pm
by bluc
You could dissolve salt in hot water?

Re: 2" Boka Build

PostPosted: Mon Jul 10, 2017 10:13 pm
by Hazardcone
Hi Guys,

I didn't use anything. Just went for it. :pray: My back up plan was to try and salvage it by making a cold finger. But as it turned out it works just fine.

I'd be interested to hear what other people have done.

Hazardcone

Re: 2" Boka Build

PostPosted: Mon Jul 10, 2017 11:12 pm
by Huntsman96
Funny enough I just today added a cold finger to my double wound coil. I have to day I couldn't reccomend it more. It has made the flow output from the coil go from about 1.5L/min to around 6L/min and now it doesn't seem to matter how much vapour I throw at it, it knocks everything down without fail.

Re: 2" Boka Build

PostPosted: Tue Jul 11, 2017 10:06 am
by Hazardcone
I'm not sure of the flow through my coil. I have a 2000w element, a 1300mm insulated, packed column. Once the head temp rises to about 45C I turn on the water so I get a trickle out of the hose. Knocks down all the vapour. The head stays quite cool. As the temp rises towards the end of the run I increase the water flow a tad more to try to keep the temp under control. I use garden
"click" type connectors. They don't leak yet....they are cheapies so they will eventually leak!

I'm wondering if the fact that I wound the coil really close, with no real gaps between the winds and the coil is long with lots of pipe in it that it's cooling capacity is good despite the lack of good flow :think:

Hazardcone

Re: 2" Boka Build

PostPosted: Tue Jul 11, 2017 6:01 pm
by hillzabilly
I would turn on ya coolant water when you turn ya power on ,it's a good habit to get into and will be safer ,just incase you are away when she hits temp.cheers hillzabilly ;-)

Re: 2" Boka Build

PostPosted: Tue Jul 11, 2017 6:38 pm
by Plumby
hillzabilly wrote:I would turn on ya coolant water when you turn ya power on ,it's a good habit to get into and will be safer ,just incase you are away when she hits temp.cheers hillzabilly ;-)
:text-+1: water is the first thing I turn on and last thing I turn off.

Re: 2" Boka Build

PostPosted: Tue Jul 18, 2017 10:59 pm
by Hazardcone
So I took my 50 mm pipe and cut a short piece of it to make my plates.
Plate cut.png
I cut the section in to two and hammered it flat.

Re: 2" Boka Build

PostPosted: Wed Nov 22, 2017 7:18 pm
by datman
Hi hazard, just wondering if you were going to bother to "t" the out put line to return to the wash. Have seen this on another build. How is your build coming along? I'm just trying to get ideas for the future and the Boka looks like a safe bet with good out put. Bubblers look awesome but above my pay grade at the moment.

Cheers

Re: 2" Boka Build

PostPosted: Thu Nov 23, 2017 7:20 am
by warramungas
When I do back to back runs through my 2" LM or CM, or used to, I had a spare coil I would put into the next bucket of wash and plumb into the discharge of the still rc coil and its discharge would go into the drain. The hot water would preheat the next wash and reduce the amount of time to heat up next run.

But I digress. I've never double wound, used salt or sand or used a cold finger in my coils. They've all been fine wound around a 1" pipe. They knock down anything reasonable for a 2" still.
At worst, and I do this out of habit more than anything, I put a copper scrubber loosely up the guts to help disperse the cooling.