2" sanitary spool shotgun with copper internals

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Jsv22
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2" sanitary spool shotgun with copper internals

Post by Jsv22 »

Hey folks! I'm working towards building a 2" CCVM and i decided to start with a product condenser while i figure out how i want to approach a reflux condenser and am still looking for a used 50L keg.

I have an extra 18" sanitary spool that I'm trying to convert to a shotgun condenser. the four copper 1/2" tubes have 4 baffles and end plates. I had some 1.5" copper that I cut and pounded out for the copper end plates. used some printed/glued templates, and cut them out with tin snips.

if anyone is doing this and has a 3D printer - if i was to do this again, i saw some really cool 3D printed templates after i started with mine (drill guide and press)- and i regret not trying that out to get better tolerances/better fit/ better surface area for soldering/brazing. c'est la vie.

i am planning on brazing the end plates and inlet/outlet using Harris safety silv 56 with proper brazing flux for stainless and MAPP gas. Im pretty confident about brazing it, but have never done stainless to copper. if i have any issues, my BIL has a tig welder/better torch and i'm not afraid to ask for help.

my next step is to drill the inlet/outlet before I start the prep for brazing. to drill these holes in stainless I plan to use a lubricant and was considering stuffing the spool with snow with end caps (it's winter here!) - to keep it very cold and prevent work hardening while I drill very slowly. i have some stainless 3/8 NPT to barb fittings, but I think I may get some 1/2" SS and use these instead. I think i'm going to make a little jig to hole the spool to make the drilling easier (i do not have a drill press ATM).

i've attached a few photos of my progress, hoping to complete the build and focus on a cold finger RC > then a keg kettle build
Attachments
shotgun materials.jpg
fitted ends.jpg
bare copper.jpg
StillerBoy
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Re: 2" sanitary spool shotgun with copper internals

Post by StillerBoy »

Copper soldered with stainless steel will not work in a condenser.. it will crack and leak over time..

Mars
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Tōtōchtin
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Re: 2" sanitary spool shotgun with copper internals

Post by Tōtōchtin »

StillerBoy if you feel that's a fact why did you make this. I'm a little confused...
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StillerBoy
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Re: 2" sanitary spool shotgun with copper internals

Post by StillerBoy »

Tōtōchtin wrote: Fri Feb 03, 2023 7:24 am StillerBoy if you feel that's a fact why did you make this. I'm a little confused...
Confused ? ? the item pictured is made using a copper tube with ss ferrules..

He's wanting to make a condenser using a ss tube/ferrules, which will not expand at the same degree as the copper plates and will cause issues of leaking down the road..

Big different in metal behavior..

Mars
" I know quite certainly that I myself have no special talent. Curiosity, Obsession and dogged endurance, combined with self-criticism, have brought me to my knowledge and understanding "

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Tōtōchtin
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Re: 2" sanitary spool shotgun with copper internals

Post by Tōtōchtin »

I thank you for getting back, I'm going to have to go for ride and think about this. Now in my mind, copper expands a lot more then steel,I have a bad memory problem but I believe it heats up 10-15 times more quicker then stainless. It would seem to me the copper jacket would pull away from the SS ferrules. Going for a putt usually clears things up.
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Dancing4dan
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Re: 2" sanitary spool shotgun with copper internals

Post by Dancing4dan »

Tōtōchtin wrote: Fri Feb 03, 2023 8:37 am I thank you for getting back, I'm going to have to go for ride and think about this. Now in my mind, copper expands a lot more then steel,I have a bad memory problem but I believe it heats up 10-15 times more quicker then stainless. It would seem to me the copper jacket would pull away from the SS ferrules. Going for a putt usually clears things up.
Tōtō
Using SS ferrules with Copper pipe works because of the contact area between the two metals and the small amount of SS. Also both the SS and copper are in similar alignment.

When you use a SS pipe and copper plates on a shotgun the contact area between the SS and copper is the thickness of the copper only. Secondly the copper is in a different alignment to the SS and likely to pull harder on the narrow solder joint between the copper and SS.

All of my stilling equipment is copper pipes and SS ferrules. Never had a failure.
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zach
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Re: 2" sanitary spool shotgun with copper internals

Post by zach »

StillerBoy wrote: Fri Feb 03, 2023 7:52 am
Big different in metal behavior..

Mars
Not much difference in the critical factor. Which material property are you referring to?

..........................Coefficient of Thermal Expansion
...........................10-6 (°C)-1.........10-6 (°F)-1
Copper ....................17.6................9.4
Stainless Alloy 304.......17.2............... 9.6

I've built shell and tube heat exchangers with expansion joints when difference between the shell and the tube coefficient is large ( stainless & carbon steel ) and the length of exchanger is large (30 feet). But in a 12" long heat exchanger with a stainless shell and copper tubes, the difference in length after a 100 F rise is 0.00002 inches. Less than a hair thickness (.002 inch) The tube sheets likely have the flexibility to bend a little if there is a good solder joint.
Jsv22
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Re: 2" sanitary spool shotgun with copper internals

Post by Jsv22 »

Thanks for posting everyone. Interesting comments, I've seen someone else do a 4" version of this. Here's the output, I have had a chance to pressure test yet, but I'm prepared to fix any issues!
Attachments
PXL_20230211_195724361.jpg
PXL_20230211_195703984.jpg
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Salt Must Flow
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Re: 2" sanitary spool shotgun with copper internals

Post by Salt Must Flow »

Looks good. For my water inlet & outlet, I bought two brass plugs or caps (depending on whether you want male or female threads). I drilled a hole through the plug, ground the contour to mate with the 2" pipe and soldered it to the pipe. Doing this just makes for a more compact setup if you know what I mean. How you do it won't affect the functionality at all of course.
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