Copper and Stainless together in condenser?

Anything cooling/condenser related.

Moderator: Site Moderator

Post Reply
User avatar
pope
Site Donor
Site Donor
Posts: 1346
Joined: Thu Feb 02, 2012 3:56 pm
Location: Tinseltown

Copper and Stainless together in condenser?

Post by pope »

Has anyone done this? Stainless outer tube (let’s say 2”), copper inner tubes and plates (4 x 1/2” copper pipe). Braze with 45% silver. I want to make a heat exchanger with 1.5” tc in/outs so welding the outer parts in stainless for cost/convenience and then brazing in the inner parts for conductivity would be a good way to go, I’m just hoping varying expansion rates wouldn’t cause this thing to tear itself apart.
"A little learning is a dang'rous thing; Drink deep, or taste not the Pierian spring: There shallow draughts intoxicate the brain, And drinking largely sobers us again." - Alexander Pope
User avatar
NZChris
Master of Distillation
Posts: 13062
Joined: Tue Apr 23, 2013 2:42 am
Location: New Zealand

Re: Copper and Stainless together in condenser?

Post by NZChris »

I use an SS inner with a copper outer for my gins and essences and it likes to break the solder and leak.

Braze or solder the bottom, but use silicone at the top to allow some movement. Leaks at the top aren't a problem unless they drip onto something important. If it is siphoning, the vacuum should take care of the leak.
User avatar
pope
Site Donor
Site Donor
Posts: 1346
Joined: Thu Feb 02, 2012 3:56 pm
Location: Tinseltown

Re: Copper and Stainless together in condenser?

Post by pope »

NZChris wrote: Wed Feb 12, 2020 10:55 pm I use an SS inner with a copper outer for my gins and essences and it likes to break the solder and leak.

Braze or solder the bottom, but use silicone at the top to allow some movement. Leaks at the top aren't a problem unless they drip onto something important. If it is siphoning, the vacuum should take care of the leak.
You're talking about a silicone gel to seal the condenser? It could work because I plan on using this in a horizontal orientation to exchange incoming water for a steam boiler with outflowing condenser coolant water, it sounds unconventional though.

Why do you use copper for the outer and stainless for the inner? I'm mostly trying to minimize material cost and maximize exchange efficiency but inner SS would not be as conductive as copper. Super curious because I know you're very deliberate with the 'why's' of your builds.
"A little learning is a dang'rous thing; Drink deep, or taste not the Pierian spring: There shallow draughts intoxicate the brain, And drinking largely sobers us again." - Alexander Pope
User avatar
NZChris
Master of Distillation
Posts: 13062
Joined: Tue Apr 23, 2013 2:42 am
Location: New Zealand

Re: Copper and Stainless together in condenser?

Post by NZChris »

Because I had a suitable length of copper and copper is easy to work with.

The SS inner is 0.5mm thin walled tube, so the lower conductivity isn't a problem.

There is no flavor advantage to having copper in the downward path for a spirit run and SS can't have verdigris problems between runs.

Another innovation was crimping inlet and outlet tubes into the ends so that the cold water enters at the lowest point and the hot water exits at the highest point, making full use of the entire length of the water jacket. The typical Liebig you see pictured has stagnant areas at the top and bottom that do little work.
Crimped Liebig.jpg
User avatar
SaltyStaves
Distiller
Posts: 1049
Joined: Sun Jun 14, 2015 5:18 pm
Location: Auckland, New Zealand

Re: Copper and Stainless together in condenser?

Post by SaltyStaves »

So far so good with my copper jacketed SS liebig. I used Harris Staybrite 8 and liquid flux. It is never subjected to any flexing, so it shouldn't stress the joints.

With the SS condenser, I can run it on my preheater with something like a dirty rum, give it a rinse, then turn around and run a gin though it. If I tried doing that with my copper liebig, I'd have a very dirty, rummy gin.
User avatar
pope
Site Donor
Site Donor
Posts: 1346
Joined: Thu Feb 02, 2012 3:56 pm
Location: Tinseltown

Re: Copper and Stainless together in condenser?

Post by pope »

I was just worried about the heating and cooling cycles on the metal causing cracking, not too much physical flexing. This will be dedicated to preheating inflowing water (55F in winter, 70ish in summer) on its way into the steam boiler, the outflow is from the product condenser so maybe 150-160F? I honestly never measure that its just too hot to touch for more than a split second. Anway if you two think its fine I'll go ahead and make one, I'll post a before build picture and at some point wrap up with an after.

Chris .5mm is so thin! That's awesome. Crimping is a good idea. I'll do TC ends but still like the efficiency of your build. Verdigris concerns are a good point, I will still build this one but I might reconsider on additional heat exchanger builds.
"A little learning is a dang'rous thing; Drink deep, or taste not the Pierian spring: There shallow draughts intoxicate the brain, And drinking largely sobers us again." - Alexander Pope
User avatar
pope
Site Donor
Site Donor
Posts: 1346
Joined: Thu Feb 02, 2012 3:56 pm
Location: Tinseltown

Re: Copper and Stainless together in condenser?

Post by pope »

Here's my 3x1/2" OD copper inside a 1.5" SS pipe. Copper plates, 45% silver braze, lots of it. No cracking or pinging on cool down, not pressure tested for leaks yet, that's for tomorrow. Need to do some sanding and buffing to get the ss to look finished, the braze isn't getting any prettier than it is currently.
IMG_1714 copy.jpg
IMG_1711.JPG
IMG_1712.JPG
IMG_1713.JPG
"A little learning is a dang'rous thing; Drink deep, or taste not the Pierian spring: There shallow draughts intoxicate the brain, And drinking largely sobers us again." - Alexander Pope
User avatar
NZChris
Master of Distillation
Posts: 13062
Joined: Tue Apr 23, 2013 2:42 am
Location: New Zealand

Re: Copper and Stainless together in condenser?

Post by NZChris »

That looks pretty good pope. Fingers crossed for you. :thumbup:
User avatar
pope
Site Donor
Site Donor
Posts: 1346
Joined: Thu Feb 02, 2012 3:56 pm
Location: Tinseltown

Re: Copper and Stainless together in condenser?

Post by pope »

I had to make two for this build so I’m heavily banking on the hope of no leaks! I can always salvage the SS shell and grind out the copper guts to swap in welded SS, worst case. But this copper will conduct heat so much better, brazing really reinforces the relative conductivity of the two metals... SS just gets cherry red so fast and stays overheated if you’re not careful.
"A little learning is a dang'rous thing; Drink deep, or taste not the Pierian spring: There shallow draughts intoxicate the brain, And drinking largely sobers us again." - Alexander Pope
User avatar
LWTCS
Site Mod
Posts: 12835
Joined: Mon Jan 26, 2009 6:04 pm
Location: North Palm Beach

Re: Copper and Stainless together in condenser?

Post by LWTCS »

Silicon Bronze rod?
Trample the injured and hurdle the dead.
User avatar
pope
Site Donor
Site Donor
Posts: 1346
Joined: Thu Feb 02, 2012 3:56 pm
Location: Tinseltown

Re: Copper and Stainless together in condenser?

Post by pope »

No I didn’t want those alloys touching my vapors, this is 45% silver, Harris safetysilv product.
"A little learning is a dang'rous thing; Drink deep, or taste not the Pierian spring: There shallow draughts intoxicate the brain, And drinking largely sobers us again." - Alexander Pope
jamesv5388
Novice
Posts: 5
Joined: Thu Feb 25, 2021 5:08 pm

Re: Copper and Stainless together in condenser?

Post by jamesv5388 »

Hello Pope, nice job on the condenser. I'm curious as to how it is holding up as far as cracks or leaks. I'm looking at building a similar shotgun with 2" s.s. tube,20" long with 5 1/2" copper tubes sil brazed at the end plates inside the tig welded tube. This will go on a as yet to be built 16 gallon 3" copper CCVM keg still. I'm starting here because I have 3' of 2"s.s.,plenty of 1/2" copper and a tig welder. Did you use any baffle plates? I'm wondering if they're worth the extra fitting, etc. in this size condenser. Also wondering about your concern using si/bronze tig rod as that would be the easiest and cleanest way for me to make the copper to s.s. connections. Thanks for any input, JamesV
User avatar
pope
Site Donor
Site Donor
Posts: 1346
Joined: Thu Feb 02, 2012 3:56 pm
Location: Tinseltown

Re: Copper and Stainless together in condenser?

Post by pope »

To be honest I have not logged a ton of hours with it but so far so good! Since last March there have been a lot of stressors that have kept me from routine - some very obvious ones but also some fallout unique to me so I haven't put in a ton of time in the pursuit of the perfect drop. One of the first things I did in a long time was rob a bottles worth of single malt out of an old once-used barrel (one of the silver linings of losing a year is that my barrels are all full). I broke the blending vessel and lost the perfectly diluted spirit; I'm taking it as a sign that my luck hasn't changed or I saw my shadow, or something, and I should return to distillation hibernation.

As a non-sequitur, I will say to anyone who might see this and wondered if I was still kicking, life is not so bad overall and I've been doing a lot of cycling on a new bike, I'm in a reasonable state of fitness and probably have more melanin than ever before in my life for the season. Not to mention I'm covid-married with a baby on the way and we got a new dog - pretty sure if this goes on a little longer I can pack all the life milestones into one pandemic. But a lot of my friends are educators and were just vaccinated, folks had theirs recently, wife is eligible in a week, so all things considered and even with the struggles I'll not list here, I'm pretty lucky even if the dust is thick on my still.
"A little learning is a dang'rous thing; Drink deep, or taste not the Pierian spring: There shallow draughts intoxicate the brain, And drinking largely sobers us again." - Alexander Pope
User avatar
LWTCS
Site Mod
Posts: 12835
Joined: Mon Jan 26, 2009 6:04 pm
Location: North Palm Beach

Re: Copper and Stainless together in condenser?

Post by LWTCS »

Pope?? Is that you?
I don't believe it.
You'll need to prove it. Who won the 1942 world series? :D
Trample the injured and hurdle the dead.
User avatar
pope
Site Donor
Site Donor
Posts: 1346
Joined: Thu Feb 02, 2012 3:56 pm
Location: Tinseltown

Re: Copper and Stainless together in condenser?

Post by pope »

Haha it is! Still alive! According to my latest blood donation I have still managed to avoid the 'rona too. With a baby on the way my WFH office will be given up as a baby room so I'm going to be forced to finish renovating the garage and moving in with my still, this could mean good things for renewed progress... then again a baby might be mildly distracting... how about you? Still getting by in these wild times?

One thing that did happen in all this was after some successful continuous runs the whole thing sat dirty and I finally disassembled it, so it just needs a soak and scrub and reassembly and I might get it fired up again soon. Coming back to the forum seems to have stoked the dying coals of the still fire somewhere in the back of my brain.
"A little learning is a dang'rous thing; Drink deep, or taste not the Pierian spring: There shallow draughts intoxicate the brain, And drinking largely sobers us again." - Alexander Pope
Post Reply