Get -40C in my fillet weld tensile break tests

"Joe Gwinn" wrote in message ... Have liquid propane in the sealed copper boiler with a tube going uphill to a copper condenser cooled by dry ice in alcohol. ... The copper stuff can be ordinary plumbing tubing and fixtures. For a one-off, plumbers solder is good enough. For a true seal, braze with phosphorus-copper brazing filler, as used for HVAC systems. ... Joe Gwinn
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The pipe fitting that enables making a condenser or similar concentric tube structure is a pipe reducer with the smaller end bored through on a lathe. Brass is easier than copper to chuck and turn. A 6-jaw chuck helps hold the reducer without (much) distortion, or you can jam a fitted wood plug into the large end.
When I learned industrial refrigeration in the 1970's this is what we brazed joints with: (Amazon.com product link shortened)

On Fri, 5 Feb 2021 17:40:49 -0500, "Jim Wilkins"
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I don't visualize this.
What I was thinking was a simple one-pipe system, with vapor going up and condensate running down. The propane inventory need not be large.
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Yeah, that's the stuff.
If you braze all the joints, you can hermetically seal the propane inside the heat pipe. Make sure that the total volume is large enough to prevent overpressure damage at room temperature. Or provide a pressure releas valve and refill before each use.
Joe Gwinn

On Friday, February 5, 2021 at 6:33:30 PM UTC-5, Joe Gwinn wrote:
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Instead of the research grade propane, the fuel grade propane (R-290) may have around 5% methane (R-50) and butane (R-600) mixed in.

On Sun, 7 Feb 2021 15:12:01 -0800 (PST), bruce bowser
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Yes. The methane will do nothing, and the butane will freeze in the condenser. As long as the condenser is large enough, it won't matter.
Joe Gwinn

"Joe Gwinn" wrote in message wrote: >The pipe fitting that enables making a condenser or similar concentric tube
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I don't visualize this.
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Boring out the stop in the reducer's small end allows the smaller pipe to pass through the fitting into the larger one, concentrically. I first did this to run a cold water feed pipe through a former heating element hole to near the opposite (lower) side of an old electric water heater tank that I'd converted to solar and mounted horizontally.
It did adequately heat water for laundry without using electricity, but it wasn't worth the fuss versus Cold Water Tide.
Are you ready for California-style electric rates and monthly allocations? https://www.sce.com/residential/rates/Time-Of-Use-Residential-Rate-Plans

On Mon, 8 Feb 2021 07:43:16 -0500, "Jim Wilkins"
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In order to draw compressed air from the upper level of my inverted propane cylinder storage tank; I bazed a half coupling into the inner end of a reducing bushing (I don't have a welder) and inserted the smaller pipe through a 3/4" "T" and nipple in the threaded boss. The branch of the "T" serves as inlet and drain.

"Gerry" wrote in message
In order to draw compressed air from the upper level of my inverted propane cylinder storage tank; I bazed a half coupling into the inner end of a reducing bushing (I don't have a welder) and inserted the smaller pipe through a 3/4" "T" and nipple in the threaded boss. The branch of the "T" serves as inlet and drain.
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Something like this, in effect? https://www.zoro.com/nibco-2-x-34-x-2-nom-c-copper-reducing-tee-611rr-2x34x2/i/G1806664/

"Jim Wilkins" wrote in message
In order to draw compressed air from the upper level of my inverted propane cylinder storage tank; I bazed a half coupling into the inner end of a reducing bushing (I don't have a welder) and inserted the smaller pipe through a 3/4" "T" and nipple in the threaded boss. The branch of the "T" serves as inlet and drain.
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Something like this, in effect? https://www.zoro.com/nibco-2-x-34-x-2-nom-c-copper-reducing-tee-611rr-2x34x2/i/G1806664/
------------------------------- I vaguely remember cobbling up a fitting that let compressed air into and oil out of a tank that had only one opening, back before I had a lathe. I may have tapped the small end from the inside and cut the two pipes running into it short enough to not meet. https://www.buyfittingsonline.com/pipe-fittings-black-3-8-in-x-1-4-in-reducing-tee-150-lb-npt-threaded-malleable-iron-ul/

On Tue, 9 Feb 2021 06:45:38 -0500, "Jim Wilkins"
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By brazing the half of a coupling into the inner end of the reducing bushing, I, in effect turned it into a coupling for the smaller pipe (1/4"IPS, IIRC) with threads on the outside to fit into the end of the 3/4" "T" giving a 3/4" close nipple screwed ito the boss of the tank with a length of 1/4" pipe extending through it up into the tank.

"Gerry" wrote in message
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By brazing the half of a coupling into the inner end of the reducing bushing, I, in effect turned it into a coupling for the smaller pipe (1/4"IPS, IIRC) with threads on the outside to fit into the end of the 3/4" "T" giving a 3/4" close nipple screwed ito the boss of the tank with a length of 1/4" pipe extending through it up into the tank.
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I think I get it now. You made the reducing bushing into a coupler for two pieces of the smaller pipe by brazing a second female thread to the back side. I had trouble describing my versions without pictures.
I think the easy way, IF you have a lathe, is to bore out a male threaded fitting or plug larger than the pass-through pipe and solder or braze it onto the pipe, then you can easily adjust the fit up of the pass-through pipe before permanently attaching it. Water pipe ODs don't closely match fractional drill bit sizes.
Instead of trying to chuck fittings directly I screw them onto a brass pipe nipple or machined fitting whose threads run truer to their OD than steel water pipe and cast fittings. The threads of machined steel hydraulic fittings also run true and they can handle more torque than brass.
Another way is to drill out a compression fitting so the tube can pass through. This has the advantage that copper tubing OD is the same as drill bit sizes, 3/8", 1/2" etc, and lathe boring isn't necessary. I did this to replace the thin spray dip tube of garden sprayers with larger copper tubing, to attach a sink spray hose. I drilled out the tank fitting but used a tapered reamer to open up the cap nut which is too small to survive a twist drill bit, and sealed the connection with an O ring. They serve as pre-positioned rapid-response brush fire extinguishers in summer and power outage hot showers in winter, with the water heated on the wood stove, and a handy rinse-off when working out beyond the reach of a garden hose.

On Wednesday, February 10, 2021 at 8:51:47 AM UTC-5, Jim Wilkins wrote:
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Switching the spigot fittings? Dod gamn good idea.

On Tue, 9 Feb 2021 06:18:47 -0500, "Jim Wilkins"
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Somewhat similar, but in iron fittings and with the smaller pipe extending through the nipple into the tank.

"Richard Smith" wrote in message
..... Yup, I know that as a PhD level scientist I have to work as a welder because everyone already ensconced in "office engineering" jobs manicured in their white shirts sees me as a "Dennis Hopper like" (think eg. "Blue Velvet" (1986) film) character of the science and engineering world ;-) If you keep the office door closed to all but your own manicured kind, you can keep reality out. Who can blame them if no-one comes and hurls them out into the cold hard world their scheme avoids? :-)
Rich Smith --------------------------------
The snobbery of "Two Cultures" exists in the US scientific community too. I first encountered it as a Chemistry undergrad, from professors who either worked with government and industry or shunned all but pure academic research, and tried to convince us theirs was the only ethical path.
As a lab manager in a government research facility I worked with both hands-on and hands-off engineers, and again the theoretical, hands-off ones could be somewhat intolerant of people who could be both. I also saw that in Mensa, mainly from mathematicians. It was fun to watch the confusion after someone who had binned me as a mere craftsman found I could and solve engineering math problems mentally faster than they could with a calculator.
Personally I've been glad to stay in the lab, designing and building hardware, and avoid boring meetings and report writing. Another lab tech made a bumper sticker "Techs can do what engineers only dream of".
Not all great theoreticians kept their hands clean: https://www.fromthegrapevine.com/innovation/albert-einstein-abandoned-refrigerator-invention

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LOL ;-)

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"Techs keep Engineers out of trouble!"