Soldering loose fitting tubing/pipe


I'm putting a 3/4 sweat fitting OVER 1/2" brass pipe, cuz, well, I think I have no choice, cuz the brass pipe will be cut, w/ no thread. The fit is loose, about .020 on radius. Do you think sweating this is still OK? Solder won't be too weak?? Other choices? Saw the JustforCopper link--might could do that on nice slip-fits, but doesn't sound suitable for loose joints.

Also, I have heavy rosin core solder, almost as heavy as plumbing solder. Is it usable for normal sweating, and for this abnormal sweating??

I guess if I had to I could braze it... been a while since I've brazed, and wasn't too swift at it when I was doin it!!

Interestingly, HVAC copper A/C piping/joints are brazed, *without* flux!! They use a funny kind of rod, sort of rectangular, IIRC. Anyone know about this??


---------------------------- Mr. P.V.'d formerly Droll Troll

Reply to
Proctologically Violated©®
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HVAC joints are done with "hard" copper and SilPhos rod.


Reply to

Wrap the 1/2" pipe with a few turns of solid #26 clean bare copper wire before soldering or brazing.

Reply to
Don Foreman

And typically with a gas-fluxer setup.


Reply to
jim rozen

This wouldn't be the old-fashion fine-thread brass would it? I once had a piece of fine thread brass break at the threads. I "fixed" it by soldering a piece of 3/4" copper PIPE over it. A very good fit. Bob

Reply to
Bob Engelhardt

Assuming this is used at reasonable temperatures and pressures, it should be fine. If cold water or drains, etc. then there is no worry at all. If something got or higher pressure, then you might have a concern.

Rosin-core is generally 60-40 electronic solder. If not for water use, you can use 50-50 (50% tin, 50% lead) which is a bit harder. If for water use, there is 95-5 (95% tin, and several different mixes for the remainder) that is MUCH harder. You should have no problem filling a .020" gap for normal uses. In air conditioning service, a .020" gap would be a concern, especially on the high pressure side.

Brazing works very poorly for filling gaps. You'd really need to find a better way to fit the parts first.


Reply to
Jon Elson

If I run into that problem (I often do) I will just enlarge part of the inner tube until I have a snug fit at some point.


Reply to
Leonard & Peggy Brown

Definitely not for loose joints.


Reply to

Why don't you "bell" the brass to fit the copper more precisely? A twenty-thou expansion won't tear the pipe.

Yep. A common, "always available" version of that particular silver solder is available wherever Forney welding supplies are sold. Their brand is called "SilFlo". It's a totally self-fluxing-on-copper silver solder with enough copper in it so that the final joint looks almost self-metal welded. Really, really NICE material to work with on plumbing of all sorts.

A warning though -- SilFlo and other silver solders don't always take on brass. Bronzes, yes; brasses, not all of them. "Test on a small, inconspicuous area before applying to visible parts of the garment."


Reply to
Lloyd E. Sponenburgh

Not always. Allot of soft copper AC linesets out there. Greg

Reply to
Greg O

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