stuck sweat joint

[MasterPlumbersKeymaster]

I have a 3/4″ copper sweat joint that I cannot get to come apart. I’ve tried tapping and twisting when the joint was hot, but it doesn’t budge at all. I’m sure its dry, it has even gotten red hot. No pipe length left to cut. Any trick or suggestions to break it free.

[SylvanLMPParticipant]

When I come across a bad joint that someone couldn’t disassemble I normally braze the joint with a self fluxing copper alloy rod BUT you had better make sure you put either a heat sink on adjoining joints or have enough space between joints to prevent losing the integrity of the other soldered joints. Sometimes using a good quality SELF CLEANING TINNING flux like Hercules can be used for the non talented brazers Good luck

[Art_xyzParticipant]

Many times when having trouble getting a fitting apart it helps to heat it up, retin it with some flux,than making sure it is neither too hot or too cool, pull it apart. If still no luck, take a pair of channel locks and adjust them so they slip over the pipe but not the fitting, than repeating the above, beat the fitting off.

[hjParticipant]

Well, I would not trust a brazed joint that had already been soldered, since the solder will prevent good adhesion everywhere except at the surface of the joint and that is not enough strength to depend on for a permanent joint.

[SylvanLMPParticipant]

Well, HJ considering the fact the brazing alloy has a tensile strength OVER 87,000 PSI and “soldering” even with 95-5 is 16,000 pounds ( 95 % tin -5% antimony FYI the tin gives it the strenth) I can fully see your concerns BELOW….

“Well, I would not trust a brazed joint that had already been soldered, since the solder will prevent good adhesion everywhere except at the surface of the joint and that is not enough strength to depend on for a permanent joint.”

Now consider the fact that as a CERTIFIED welder (like most U/A journeymen trained plumbers) I have used several types of filler metals and had great success with only the outside of the fittings Welded/Brazed.

I can understand your concern about capillary attraction. After all the water pressure this poster asked about HAS to be around 60 pounds HUH?

If you had read about why the outside of fittings should be cleaned during brazing you would know the cup of the joint does not have to be filled in the brazing process as the strength is so over kill as with most brazing rods.

A properly brazed joint is actually stronger than the base metal. You honestly should invest in a stamp and contact the copper development association (CDA) and you just may learn something regarding this profession.

The AWS (American Welding Society) offers classes for folks who HAVE NO IDEA about what they are talking about in metalurgy/welding

When copper freezes and splits especially on Air handler coils NOTHING beats closing these splits and brazing the gaps with copper based brazing alloy ESPECIALLY knowing you don’t need any flux if the copper is properly cleaned.

Copper tubing is one of the easiest
non ferrous metals to repair VERY FORGIVING.

I cannot begin to tell YOU how many 1st year apprentices braze the outside of split copper/bronze and brass piping.

By the way there are some cases where you DO NOT want the filler metal getting into the fitting/system. LIKE a filter drier on AC systems which by the way operate at a much higher pressure temperature than domestic water and ALL THIS with only “Surface brazing” and no flux
Amazing HUH the knowledge required to be a REAL PLUMBER?

Have a great one

[Author]

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