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The 4" Copper Cored Dephlegmator Attempt

Florida ground water just too warm, going to try to make a copper cored dephleg, since copper supposedly has 300 the heat transfer of stainless...

starting this morning by turning down a bubble cap plate....


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  • Using some blocks to position slightly below the edge so I don't mess up the tri-clover seal



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  • And tack welded...


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  • And started welding..... and then the weld sounded like I was boiling water off, but there wasn't any... out of argon(you can see the weld change, left side is no argon), so I switch to the other tank... the 300 cubic foot tank I got from a friend that I thought was full isn't..... frack, frack, frack... ( except I didn't say frack)....

    To be continued......


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  • Oh man why that way?

    Make a copper cylinder 5mm smaller than your stainless shell and build a drop in copper condenser.

    That way the outer copper shell is an additional cold surface, to boost the tubes. Construction should be easier also.

  • I don't have the copper to make the cylinder... and the coolant holes still have to come through the side for my setup... going to use 3/4" tri-clover ferrules... I do have the copper plates and lots of 1/2" copper tube laying around...

  • With the tubes added


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  • Looks good Michael. Wish I had a tig :((

  • You know, they say that "a friend with a boat is better than owning a boat!"...

  • Got cha loud n clear. U wanna tig some stuff for moi?

  • Not worried about stress fractures?

  • Excellent stuff.

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  • sure captain.... I trade for rum...

    @grim - I can afford to waste the parts for a 4" (for an 8", prolly not... would want a cartridge) I also sat with the tig on the copper plate for a while just warming it up before I tacked it so it expanded, I started with it a bit undersized, hoping to have it in tension when it cools to keep it from buckling...

    then again, maybe the point of this exercise is to test/demonstrate the supposed 300x cooling capacity of a copper cored one to encourage someone ahem... to get the local shop to get good at welding copper...

  • edited August 2014

    Conductivity isn't 300x, too many zeros. It's like 20x-30x at the temperatures we use. It doesn't translate into 20-30x smaller.

  • Not sure where I got that 300x, looking now it says 25 times, I will be happy with 2x.

    I know that I can tack weld a piece of stainless and pick it up a few inches away, tacking a stainless ferrule to a 2" copper tube 3' long was hot at the other end, even through heavy welding gloves!

    Also, i believe the near zero gradient from top to bottom will mean running coolant from top to bottom will be just as efficient and clear bubbles...

  • edited August 2014

    Your welds (err braze?) look great though. I've tried copper stainless a dozen times and it looks like crap .

    Trying to keep the arc on the stainless, since once it touches the copper it sucks the heat right out.

    Hmm - do you have an AC tig? I've only got a small DC everlast. An old timer laughed at me and told me to get the copper nice and hot with a gas torch before even starting.

  • Turns out the thermal conductivity of water is 10-20x worse than stainless, who knew..

  • @grim said: Turns out the thermal conductivity of water is 10-20x worse than stainless, who knew..


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  • My welds were done with is DC, although I have thought about trying AC... what is wierd is that the backside of the bad weld looks the best, lol.... from what I have learned by trial and error, you want the tig to heat the copper until you can have the arc in the middle of the two metals... this one worked better than the stainless ferrule to the 2" tube I think because the copper was smaller than the stainless, not much to heat up the 4" bubble cap plate... if you were welding a fitting on a really thick, large piece of copper, I would agree with heating it by some other means... copper sucks heat, I guess that is why they have us use copper along with reverse polarity to melt the tip of the tungsten into a ball for doing aluminum... it takes some serious heat to melt tungsten...

  • @grim said: Turns out the thermal conductivity of water is 10-20x worse than stainless, who knew..

    until you circulate it ;-)

  • @Law_Of_Ohms said: maybe try helium in place of argon

    I should read up on that, and a helium tank would be fun for parties, but argon does well, whereas running out of argon, not so much.....

  • edited August 2014

    Argon in balloons is a hoot, they sink like a rock.

  • @grim said: Argon in balloons is a hoot, they sink like a rock.

    Oxy-Acetylene in balloons is a hoot.... just don't stand too close when you blow them up!

    I called the welding shop, they are bringing me a full 300 argon tank tomorrow, and I am swapping the 125 tank for a A-75 mix(25% argon, 75% helium) but they have to order it, I will wait on the copper-copper welds for that gas, I cry thinking about RDD's problems on his beautiful condenser.

    shop only charges $10 delivery fee, I think about all the times I lugged those tanks to them and sigh....

  • @CothermanDistilling so what's your favorite cup-o-tea when it comes to the grog? What I need done is a 2" ferrule for an element and an 8" ferrule to replace a 7" lid lip so my milk can lids fit the oddball opening. Sounds like this is gonna get expensive. Been wanting to come piss on yer toilet, so what say u?

  • 8" ferrule is a bit of work, after doing a 6" on a sankey keg, I learned that I need to make a back-gassing fixture for that... should have my gas delivered by the end of the week, so next week might be good... with smaller fittings like 2", I have had the best luck with the hole being smaller than the ferrule and welding from the inside while gassing the outside, but with a 6" or bigger, I think I can gas the inside and weld the outside with the right shield..

  • I hear you and it is not going to be easy. The can has to be trimmed, then the ferrule needs to be tig welded. It is going to be a PITA but I just had to have the old timey can. and now I have to make it useable. It's a work in progress project with no rush whatsoever. I'll keep u posted. Now back to your project...hijacking your thread, again...oooppss!



    What I hope to achieve when it is done.


    Be out of town next week. I'll get back with you.

    milk can project 001.JPG
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    milk can project 003.JPG
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    milk can project 004.JPG
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  • that is doable... the key is back gassing to keep the backside from looking like a black caterpillar ;-)

  • I do not know how this guy done it or what gas mix he used but his welds/brazes look farking awesome to me. I am assuming, errr, ass of u-n-me, he tigged it. Looks like the copper did not get a chance to rob the weld of the precious heat. Dunno. Long shot, I can contact him and ask, but if @Lloyd can get his factory to produce stainless/copper stuff like this, well then it sure would be the cat's meow!!



    copper stainless tig 001.JPG
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    copper stainless tig 007.JPG
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  • this was my first attempt about a year ago. Becoming good is just getting used to the heat difference. I could get close to that after a couple more, which means Lloyd's factory could if motivated... Going to get 75% helium-argon tank, it takes less heat from the weld and helps porosity when copper-copper


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  • @captainshooch

    Try a 6in to 4in reducer, use the lip of the 6in part to weld to the can.

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