Shotgun / dephlegmator on top of boka

[cede]

Hi all,
I've searched the forum and google for some examples of bokakobs using a shotgun condenser for a bok instead of a coil.
I found about nothing !
The time I'm thinking about the next flute, I wanted to build a new bok to play with and do some vodka.
Here's why I'm looking for someone using a shotgun condenser on a bok: I'd like to be able to reuse the condenser on the flute as a product condenser. Think modular !

It's not that I do not like coils, but 1/4 OD is somewhat flow restrictive. So I thought about double winding around a cold finger, to double the flow, but I'm not sure as I could not reuse the coil for the flute.

So let's say I build a shotgun condenser using 4x 1/2 M tubes or 5x 3/8 tubes if I can find some here, 14" long. Do you think this would be enough for the bok and the flute ?
I read it can kill 4200W or 75W per inch for 1/2 so this seems fine to me, but I'd like some advices !

Thanks.

[pfshine]

I can't remember who but back in 2013 I think someone did it and it worked just fine. I can't remember the thread, I'll see if I can find it.

https://www.google.com/search?rls=en-us ... enFHNhA%3D" onclick="window.open(this.href);return false;" rel="nofollow

[Expat]

Im using a crossflow condenser on my bok. Works great. Similar in function to what you are proposing.

[Saltbush Bill]

There is no reason that it wont work , just as long as the dephlegmator is capable of knocking everything that comes up the column back down. For that reason I think It might help to make it a little longer than average but not by much.

[cede]

pfshine, you're better than me at choosing the keywords ! First result was the thread from Torp.

Well thanks to Expat and SB for confirming my thoughts.

I think that I might lengthen a bit the tubes to 16" just to be sure that I'll knock down all the vapors of the flute.
The condenser will be overkill for a bok at 2500W max but who cares

I'll post a few pics when I'll manage to make something that I'm not ashamed of !

[Expat]

16" is what I used for mine, it doesn't even blink at 3kw.

Shotgun and crossflow are different implementations for pipe size selection ( example I used 21 of 1/4"), but 4 of 1/2" in a 2" shell is a pretty common setup I believe.

[bluefish_dist]

I used a 4 tube on top of my two cups boka/vm. Worked fine. It was not as effient as a coil of CSST, but worked.

[pfshine]

pfshine, you're better than me at choosing the keywords ! First result was the thread from Torp.

All I did was type in "shotgun boka" into the he Google search.

[cranky]

I ran a shotgun on my boka. It was 10 or 12 inches long. In theory it should have worked fine, in reality it worked ok but it could easily be overwhelmed because the vapor speed would increase in the tubes of the shotgun and although it would condense the vapor if run too hard it could push the condensed liquid up and cause it to spit cold liquid right out the top so I had to run fairly slow. In the past I've told people if they are going to try a shotgun on a boka, make sure they use a longer condenser than 12 inches, which is exactly what you are thinking. I think would be fine for a boka but to later turn around and try to use it for a dephleg for a flute you are likely to run into problems with too much knockdown power due to it being too long resulting in control issues. Personally I would recommend one made from CSST.

[cede]

I think would be fine for a boka but to later turn around and try to use it for a dephleg for a flute you are likely to run into problems with too much knockdown power due to it being too long resulting in control issues.

I would not use it as a dephlegmator on a flute, but as a product condenser

I called a guy doing HVAC because I was looking for pipe a bit smaller than 1/2 to be able to put more surface in the condenser.
Looks like he will drop me a bunch of pipes left overs that he can not use in refrigerant circuit because of contamination.

[HDNB]

can not use in refrigerant circuit because of contamination.

but you'll drink from them?

[pfshine]

Yes. Dirt is contamination. So is a bit of oily substance that can easily be removed for our needs. Unless it's really nasty contamination. But then again people have used old 4" shit pipe to make plated columns.

[cede]

HDNB, yes I'll drink from them after a cleanup.
Contaminants in Hvac can be just some particles or greenish that could be bad for a compressors.
Every pipe has to be free from debris and corrosion, things we can clean but that they won't even try to clean for their usage.

[zapata]

My reflux still has a crossflow condenser on top of boka LM head (though not the popular slant plate boka design).
That's like an inside out sideways shotgun on a not quite what OP meant but still a boka. Yeah, so I don't know if it's relevant or not, but it works great

[cede]

I tested a weld for leaks tonight and.... Ok got to buy a few more ferrules as I need to practice a little bit more.
I was not confident at all on the first weld, seemed really crappy.
I never did silicon bronze, and flowing is not what I thought.
Will try to post pics tomorrow as I left parts at work.

[pfshine]

Are you tigging it? If so what is your procedure?

[cede]

Yes I am tigging copper and stainless with silicon bronze rod, it's considered like brazing.
I do like I learned: backflush with argon, direct heat more on copper because it dissipates more heat and try not to do bubbles
I'm not that good.

If you want to see really neat work, check this thread of VictoryRay viewtopic.php?f=17&t=69691
He did a really good job.

[pfshine]

What kind of tungsten are you using? Sharp tip or slightly blunted? Did you clean the living piss out of both the copper and SS? If you pre heat the copper lower down as to not oxidised the preped joint it can help allot. Do you dip and move or do you like to lay your wire down and wash over it? I prefer the later.

Edit to ask: did you clean the silicon bronze as well?

[cede]

I use lanthanated as per what the welders told me at the shop and it's sharp tip.
I cleaned the copper with a wire brush and I sanded the stainless to rough up the surface a bit.
I also cleaned the bronze rod with scouring pads as there was some green on it.
I did not preheated the copper at all.
I put some aluminium paper inside the copper pipe and made a cap on the ferrule to keep the argon gas inside.
I tried to lay the wire and heat it and also dip and move but I prefer the first one.
I just feel that the 3/32 is a bit too big. I'll try some 1/16.

This what happened, and I must improve
I also must remember to cut the power at the pedal before moving the torch away ! It's not mig... I did wonderful arcs that can be seen on the stainless ferrule.

I'm no way professional welder but I have help from welders at the shop.
I could have them make this, but I want to learn and succeed by myself

[pfshine]

You gotta walk the cup to get proper fusion of both base metals. It looks like you are cold as well, try bumping the heat 5-10 amps. I never did care for the lanthanated, I was partial to thoriated for most things. I will tell you what not to use, pure tungsten, it is only good for like 15 amps or something like that and it balls and spits.

[cede]

Thanks for your advices pfshine
I'll train again and again !