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Re: MacBoka users

PostPosted: Wed Aug 09, 2017 1:25 pm
by hillzabilly
If I was trying ta get flavour from it,I would try removeing 90% of the packing leave the output valve fully open ,and drop ya power to 1000-1400wt after heat up.cheers hillzabilly ;-)

Re: MacBoka users

PostPosted: Wed Sep 20, 2017 8:49 pm
by Bundaboy
Ha! I was wondering why I only get 93% whereas others get 95% and have just discovered it's because I have a 600mm column instead of the 1 metre column at least one other user has mentioned.

Ok, I now have a 600mm ss column tightly packed with copper mesh (6 rolls), if I add another 600mm section could anyone suggest how much additional packing I would need? Surely another tightly packed column would be over the top? Cheers.

Re: MacBoka users

PostPosted: Thu Sep 21, 2017 5:52 am
by scythe
Nope, bokas are made for neutrals and are generally fully packed.
Its the packing that does the purification.

Altho one would think that if 6 mesh bits gets you to 93% then at most you would need another 3.
Maybe...

Re: MacBoka users

PostPosted: Thu Sep 21, 2017 6:16 am
by Professor Green
I added an extra 500ml section fully packed and it worked a treat. I just used stainless scrubbers for that section rather than copper mesh.

Cheers,
Prof. Green

Re: MacBoka users

PostPosted: Thu Sep 21, 2017 10:28 am
by Bundaboy
scythe wrote:Nope, bokas are made for neutrals and are generally fully packed.
Its the packing that does the purification.

Altho one would think that if 6 mesh bits gets you to 93% then at most you would need another 3.
Maybe...


Ok, yes I was thinking that later although I was also thinking I may have my 600mm section packed too tightly (I actually have seven copper rolls packed in there so it is very tight but it seems to work well as is and have had no flooding), but yes no point in the column extension without it being packed (although it seems I only need the *equivalent* of 1 metre for 95% according to theory). Cheers.

Re: MacBoka users

PostPosted: Thu Sep 21, 2017 10:29 am
by Bundaboy
Professor Green wrote:I added an extra 500ml section fully packed and it worked a treat. I just used stainless scrubbers for that section rather than copper mesh.

Cheers,
Prof. Green


Yes, that would be an option too, I probably have enough copper in there for sulphide removal as is - I will compare costs. Cheers.

Re: MacBoka users

PostPosted: Tue Dec 12, 2017 3:20 pm
by Bundaboy
I have been reading a few Boka posts around the traps and "only 1400W" or similar has come up a few times.

I have been running mine at around 450-500W. This allows me to reduce both the energy and the water costs whilst maintaining the "drip rate" others on this topic have advised.

I seem to get results consistent with others running the unit, although I have long felt my "tails" are longer that I would expect, and have been trying to ascertain a) whether they are unreasonably long, and b) if so why?

I realise the length of the column has an affect on the "purity" of the product but as the standard for a MacBoka is 600mm (as I have) I would have expected others to be getting similar results.

As the Boka is a liquid management system I wouldn't have thought that power as much to do with it as long as the vapour is reaching the condenser and falling back on the plates.

Does anyone know if input power can affect the reflux action of a Boka? (my searches haven't turned up anything definitive).

Cheers all.

Re: MacBoka users

PostPosted: Tue Dec 12, 2017 4:18 pm
by woodduck
Power will effect the end results as the more power the more reflux/cycles up and down the more pure/cleaner the product. If your power isn't high enough your only getting a small amount of vapour up the column and that is what your taking, you need more than what your taking off so it flows back down the column to mix with the rising vapor, make sence. I would think 500w would be very low. I used to push my boka to the point where it was only just holding the vapor from escaping out the top. Probably close to 1800-2000w.

Re: MacBoka users

PostPosted: Tue Dec 12, 2017 4:57 pm
by Bundaboy
woodduck wrote:Power will effect the end results as the more power the more reflux/cycles up and down the more pure/cleaner the product. If your power isn't high enough your only getting a small amount of vapour up the column and that is what your taking, you need more than what your taking off so it flows back down the column to mix with the rising vapor, make sence. I would think 500w would be very low. I used to push my boka to the point where it was only just holding the vapor from escaping out the top. Probably close to 1800-2000w.


It makes sense that I need to make more than I am taking off, I am, I have the needle valve barely cracked open, if I open it a turn or two I get a stream, albeit it reduced ABV. I would have thought that as long as the vapour is reaching the condenser it would cycle up and down the column as normal.

I didn't specifically say but I am getting 94%, but certainly if it's not refluxing enough that could be my problem.

Re: MacBoka users

PostPosted: Tue Dec 12, 2017 5:34 pm
by Bundaboy
I found this:
"On a reflux still you want the proper amount of vapor sent to the column to produce the proper amount of reflux for the still to work at an optimum level. Too little heat results in too little vapors and reflux giving you poor results and shows up as higher temps on the columns thermometer. This results in a lower ABV product because not enough reflux is returning to the column for the packing to work properly. Not having the proper amount of reflux returning to the column will not allow the needed column temp gradient to be achieved, more hot vapors than cooler returning reflux showing a higher temp than wanted. Now a too high of a heat input creating to many vapors will more than likely flood the column where there is too much reflux returning to the column and to much vapors coming from the boiler causing the vapors to hold the reflux in the column not allowing it to return to the boiler. This will cause a safety problem and poor performance. You need to be able to adjust the heat input to achieve the correct amount of vapors to achieve the correct amount of returning reflux and rising vapors in the column. This is different for every still. And as above the ABV of the boiler charge will also change this so it needs to be adjusted for your particular still setup. There isn't a one size fits all type heat setting it's all as per still."

Which makes sense as far as it goes BUT it doesn't tell me how to find that optimal setting - I have been working on the assumption that if I get 94% I am optimal for this length column.

Edit: (oh and 76.4C steady)

Re: MacBoka users

PostPosted: Tue Dec 12, 2017 8:38 pm
by Bundaboy
Boy oh boy, talk about putting theory into practice, you won't believe this (I am only posting this because of what I posted immediately above):

Ok, so I decided I would up the power from 450 Watts to 1400 Watts - now, before I go on, lets get one thing straight - this was my OWN choosing - this was not the result of any one else's advice. No one is to blame for this but me. I knew there was a risk associated with this because the controller I have had a faulty 30 amp fuse and all I had on hand was a 10 amp fuse (I am an electrical engineer, electronics technician, and qualified electrician - I was well aware of what I was doing). This, in it self, was no big deal: at the power levels I normally use that is fine, however, upping to 1400W was pushing it, and eventually the fuse blew (actually the solder on the cap melted).

Ok, I expected that (to some extent anyway, I *was* hoping to get away with it) so what to do? Well, I thinks to meself (always a dangerous thing to do), why not run it flat out with more water flow - every one else seems to do it (except they don't normally have 2400 Watt elements) and I only have ~4 hours to go to finish, only ~2 hours to opening the needle valve for tails, what could go wrong?

Going well until I noticed that tell tale smell of alcohol vapour in the air, not enough water flow? No, all the vapour was being knocked down, product too hot? No, feels luke warm to the touch, oh no! not a seal leak?! Check the seal at the top, ok, check the seal at the head, ok, check the seal at the top of the boiler, which incidentally is covered by my insulation wrap (which, perhaps, I should have removed for this experiment)... sigh... thar she blows. That's funny, I think, I thought that seal was fairly new, and it was ok for 8 hours of this run - and then it dawned on me - what did they say would happen? Flooded column. aaaaaagh!!! Shut her down for the night.

So there you are, proof that you can go too high with power, now to work on the lower limit.

Have a good laugh at my expense but for God's sake don't do this at home, I am not normally this cavalier with safety, the thing that bothers me most is how long it took me to eventually convince myself something was wrong and shut down, *especially* after posting that info above.

Re: MacBoka users

PostPosted: Tue Mar 06, 2018 8:09 pm
by Enigma
Hi Bundaboy, thought l better make a correction of your last post in case any other newbies might read it. I think you( almost sure) you meant to say increase to 2400w not 1400w. For the other people’s interest, Ohms law, voltage x amps =Watts. Or Amps = Watts divided by volts. Don’t mean to offend, just trying to share knowledge . Also check out SPP (spiral prismatic packing) for your still, seems to be more efficient than SS scrubbers. Im only new to this, but was very happy that my first run was 95+ at 1l hour.

Re: MacBoka users

PostPosted: Wed Mar 07, 2018 3:45 am
by Bundaboy
Enigma wrote:Hi Bundaboy, thought l better make a correction of your last post in case any other newbies might read it. I think you( almost sure) you meant to say increase to 2400w not 1400w. For the other people’s interest, Ohms law, voltage x amps =Watts. Or Amps = Watts divided by volts. Don’t mean to offend, just trying to share knowledge . Also check out SPP (spiral prismatic packing) for your still, seems to be more efficient than SS scrubbers. Im only new to this, but was very happy that my first run was 95+ at 1l hour.


Hi Enigma, no I definitely meant 1400W, 2400w would be running it flat out. In this case, with the aide of my controller and my power meter I was definitely at 1400W.

No offence taken at all, but as a qualified electrician, electronics technician, and bachelors degree in Electrical Engineering I am vaguely familiar with ohms law LOL. Of course, in this case ohms law is not entirely applicable as the controller, is of course, altering the duty cycle of the mains supply such that the average power (actually average rms power, but that's splitting hairs) delivered to the wash in the boiler is equivalent to 1400W (or there abouts).

Where I have erred, perhaps, is in not explaining myself well enough. You are probably working on the basis that the 10 amp fuse would blow at 2400W not 1400W, and in that you have a point, but it really comes down to the poor design of the cheap controller I am using, the position of the fuse is suboptimal at best and thus it is not only being heated by the current passing through it, but also by the heat being dissipated by the controller itself. Other factors, such as it being a fast blowing fuse etc. come in to it as well, but the main thing is that it definitely blew at 1400W (eventually) forcing me to ditch the controller and run at 2400W which caused the column to flood etc etc.

It's important for me to emphasise that this was a jury rig mod I made with what I had on hand at the time and there was always a risk of this happening. The fuse blowing was a minor issue compared to the column flooding, and the latter issue was the one I was emphasising.

I find I can run the boka at 450W and hit the correct head temperature with a reasonable flow rate, but what I don't know is if I am hitting full reflux at that power - as I only get 93% but after further research I am comfortable that that is correct for the length of my column (600mm).

You say you are getting 95%? Is that taken at 20C (or suitably adjusted for a higher temperature)? What is the length of your column?

BTW I have copper mesh.

Cheers!

Re: MacBoka users

PostPosted: Wed Mar 07, 2018 5:28 pm
by Enigma
Hi, just have you say, this is a great hobbie for the few of us who enjoy a drink after work. Only just joined this forum but have been searching for as much information as l can for awhile. Yes to question about temp correct ABV, was coming out at 28.5c @ 98% when cooled to 20c @96%, which might mean my alcometer is out abit ( thought 95.6% is azeo ) Have some pics of my Still and readings in my first post at Welcome Centre, ( Hello Fellow Craftsman ) Still very much a newbie, only done 2 turbo washes but have. TPW almost ready to boil. Thought l would start with the Turbo, then have a baseline to compere with. I think lm abit like you, start with the boka because they seem fairly easy to operate then maybe try something next level up when l get better at noticing the subtle differences in cuts. Again, l have to say, this forum is a wealth of information if you look .

Cheers

Re: MacBoka users

PostPosted: Wed Mar 07, 2018 6:10 pm
by Bundaboy
Enigma wrote:Hi, just have you say, this is a great hobbie for the few of us who enjoy a drink after work. Only just joined this forum but have been searching for as much information as l can for awhile. Yes to question about temp correct ABV, was coming out at 28.5c @ 98% when cooled to 20c @96%, which might mean my alcometer is out abit ( thought 95.6% is azeo ) Have some pics of my Still and readings in my first post at Welcome Centre, ( Hello Fellow Craftsman ) Still very much a newbie, only done 2 turbo washes but have. TPW almost ready to boil. Thought l would start with the Turbo, then have a baseline to compere with. I think lm abit like you, start with the boka because they seem fairly easy to operate then maybe try something next level up when l get better at noticing the subtle differences in cuts. Again, l have to say, this forum is a wealth of information if you look .

Cheers


Stupid me didn't look at your details, your column is twice the length of mine and that would explain the difference - I really need to get an extra section in, although the difference between 93 and 95 isn't all that great but it would be nice to be amongst the 95 crowd ;-).

That's a very nice looking bit of kit you have made for yourself, well done. I particularly like how you have insulated it, very neat indeed.

When you have had your fill of TPW try an FFV, I would be interested to know how you think they compare.

Cheers.

Re: MacBoka users

PostPosted: Mon Feb 18, 2019 8:49 pm
by bluc
What needle valve on off take are you fellas using?

Re: MacBoka users

PostPosted: Mon Feb 18, 2019 10:16 pm
by Bundaboy
bluc wrote:What needle valve on off take are you fellas using?


C-LOK
Five Star Distilling
3/8" BSP
SS316

Re: MacBoka users

PostPosted: Tue Jul 14, 2020 12:39 pm
by Bundaboy
Is anyone running a 1 metre (or greater) column version? If so can you tell me your wattage (if electric) please?

Re: MacBoka users

PostPosted: Tue Jul 14, 2020 6:34 pm
by bluc
my packed section was 1.2m from memory 1800w :handgestures-thumbupleft:

Re: MacBoka users

PostPosted: Tue Jul 14, 2020 6:45 pm
by Bundaboy
bluc wrote:my packed section was 1.2m from memory 1800w :handgestures-thumbupleft:


I'm larfing then! Thanks :handgestures-thumbupleft: