CU air lines for home shop - what solder?

Thank you all for the responses to my prior question. I am going to use 3/4 inch diameter CU. Now what solder? I have readily available:
lead free, 60/40, silver (OK, silver braze).
And as the year winds to a close - many thanks to the collective group for all the USEFULL and interesting knowledge (both on and off the metalworking topic) that I have gained by reading this list for the past year (and the better part of the last half decade)
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What do you feel most comfortable with making good joints? ...use that! I think any joint alloy will be OK, but others may have better ideas. If you use the no-lead, there is a flux called "Nocorrode", it's magic! And of course, clean, clean, clean! If you so the silver solder, I use a flux from the jewelry industry called "Crystal Flux" made for silversmithing. It's magic also.
Better yet, do it in black pipe. Oh, am I showing my age? I don't know why, but I feel uncomfortable with copper air lines.

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Real men have their own pipe threading hardware... ;)
Gregm

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If I really wanted to use copper for air lines I would use refrigeration copper and silver or silfoss solder. It's much stronger than water copper and soft solder and designed for higher pressures. Dave

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    --Personally I'd recommend flare couplings. Easier to change things if the layout of the shop should change.
--
"Steamboat Ed" Haas : Om mane padme hum
Hacking the Trailing Edge! : when does the money come?
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On 23 Dec 2003 05:26:01 -0800, snipped-for-privacy@c3net.net (Aribert) wrote:

I'd go with a low-temp silver-bearing solder like Harris Staybrite. It's much stronger than Pb-Sn (about 24,000 PSI), wets much better, and melts at low enough temp (about 500F) so you don't significantly anneal the copper.
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(Aribert) wrote:

"Don Foreman" <> wrote in message ...

Don, You got my vote on the Harris solder. I plumbed a 28 bay auto shop a few years ago all in 3/4" copper. I used the Harris Staybrite 8 silver solder through out the system. Not one leak or problems at all to-date. I used the corresponding Harris flux (stay-clean). The system is driven by 2 IR compressors in tandem. I used hydraulic rated hoses between the compressors and the manifold. The system also uses a refrigerated dryer in-line.
By the way, this Harris low temp solder is also excellent for stainless steel work.
PJ
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Don Foreman wrote:

I don't doubt the performance of Staybrite for a second but does it have an advantage over sil-fos(sp?)? Am I correct in stating that sil-fos is significantly cheaper? I know that the sil-fos does not require flux.
Ted
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"Ted Edwards" <> wrote in message ...

I believe that sil-fos is a brazing alloy and requires brazing temps. Staybrite is a low temp high strength silver alloy solder. It does not require the skill or learning curve that good brazing joinery needs (or a high output torch). Just my 2 cents..
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Aribert wrote:

I think 60/40 would be adequate but there is an alloy of Copper and Phosphorous called, IIRC, sil-phos. This requires no flux and makes a much stronger joint than soft solder. It is also much cheaper than silver "solder".
Ted
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I used Glued ABS (?white plastic stuff sold for water pipe) for air lines at 125 psi in my old shop. I used the same pipes for 15 years and never had a problem with them. Would do it again in a heartbeat.
I also soldered a large number of joints in a refrigeration system using copper pipe (many more joints than the average system, because of the home-made kludged up nature of the beast I was working on) with 50-50 solder. Worked perfectly, never leaked.
I also used Sil-fos, and I liked it better. Not so touchy about getting the solder flowed in the whole fitting as soft solder. Soft solders with a little antimony are stronger,(Pb95-SB5) and solder just as easily. Avoid HMP 95%lead,1.5%silver,SN the rest). Melts at high temperature and is weak mechanically.
The REAL magic trick in soldering copper is to clean the pipe until you see shiny copper before you solder...but I would still use plastic....
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    Then you have been more lucky than some in this newsgroup. As I understand it -- when they *do* fail, it can be spectacular.
    It may be something as simple as how much oil vapor gets carried into the lines, as I understand that the oil can make the plastic more brittle.
    Enjoy,         DoN.
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Is this *really* true? I've heard a great deal of give and take on this issue here in the past, and as for me, I've always found it expedient to simply use copper lines (with ordinary plumbing solder, btw) for the few air lines in my shop.
But so far I cannot recall anyone who's described a catastrophic failure of pvc or abs air line that happened personally to them.
It may be that everyone here is smart enough not to use the plastic. Or that my memory is getting more selective with age. :)
Jim
================================================= please reply to: JRR(zero) at yktvmv (dot) vnet (dot) ibm (dot) com =================================================
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jim rozen wrote:

I used to use plastic. Nobody was hurt, 2 seperate ruptures, one very soon after original install, the other was quite some time later. A body was proximate to the first. No injury. I use copper and some small sections of rubber air hose at compressor to line, and a couple other spots that were "acrobatic" installation points.
mj
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DoN. Nichols says...

Interesting comments about ruptured lines...Never happened to me. I think I had a big commercial sized water filter stuck in the line to catch moisture and oil, now that you mentioned it. It was present to keep the air cleaner coming into my shop, not to keep the lines clean, but perhaps it had an inadvertent consequence in keeping my plastic pipes from failing. I have been out of that shop for 11 years now, and haven't bothered to pipe air around this one. The old shop had the compressor in a storage building behind the shop. Keeps the noise out of the shop and gains floor space.
Brownnsharp
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