Copper-sweating question

[e36jon]

Greetings all

I am working on some plumbing retrofit in my garage and am having a problem I can't figure out. The very last joint in a day long project (All day yesterday) just won't sweat. It's behaving like it's wet, where no amount of heat will get the solder to run. I took it apart this morning (heated it up and used a spreader-clamp and some vise-grips.), cleaned off all the old solder, made sure it was bone-dry, re-fluxed it and tried again with the exact same result: Solder just breaks off in 1/4" pieces and won't melt / fill joint...

I was able to get the left side of the t-joint done no problem, so I am flummoxed.

The joint in question is circled in red, below.

Any thoughts on what's happening? Any advice on how to finish the job? I'm beat-down at this point but would love to get this finished (I need a bath!).

Thanks in advance for the help.

Jon

 

[evildky]

I've never had a joint that wouldn't take unless it was wet. you sure you aren't getting some water running to the joint area when you try to sweat it? You could cut the pipe back further, add a coupler and a fresh piece of pipe. Or just swap it all over to pex

 

[Movover]

unhook the pipe and bend it down I will almost say you have water in there. It only takes a little to make it an un-solderable connection.

 

[Shootinok]

unhook the pipe and bend it down I will almost say you have water in there. It only takes a little to make it an un-solderable connection.

Agreed
If you keep getting water there you must stop it to get the joint to sweat.
I once had that problem and couldn't get the water to stop weeping. I stuffed a piece of bread uphill of the joint and made a good joint.
Then opened the end and blew out any left over pieces of bread that worked like a little sponge.



Sent from my iPhone using Tapatalk

 

[bochnak]

I stuffed a piece of bread uphill of the joint and made a good joint.

Make sure to use cheap white bread, no crust. I used some rye bread or something and clogged everything downstream. Spend a good hour unclogging everything.

Do you hear popping when heating up joint? That is an indication of water present.

 

[rlitman]

With a big enough torch (a real plumber's torch), I can heat the pipe a foot away from the joint, which boils off any water dripping down towards the joint. Liquid water will screw up the sweating, but steam will not.

 

[Pig9r]

Using MAPP or propane?

 

[The Tool Tyrant]

The bread trick is an old plumbers trick and works great. I've encountered the same issue in the past, as others have stated, it only take a little water to ruin your day.

 

[ratdoggy]

Using MAPP or propane?

Unfortunately it's not real MAPP gas anymore but it's still hotter than propane.
Can not have any water present at all...
Use the white bread trick and maybe take the aerator off the faucet you are going to turn on

 

[e36jon]

Thanks for all the advice gang!

I went back down after writing the original post and gave it another try without undoing the joint again. I think I may have over-heated it the first time (Or there was some water). A half hour later, after a loooong time heating (I am using propane) it finally took and held pressure!

Guess it just didn't want to mess with the collective brain-trust here at Garage Journal...

Cheers,

Jon

 

[malibu101]

Glad to hear you did it.

Just wondering this on your problem--
IF the pipe system is totally sealed, meaning no place for air to escape.
Could the air pressure (from heating the pipe) push out this last joint causing the solder not to flow?

 

[BD1]

Glad you got it. Sometimes you need to have something open to prevent pressure build up. If you were doing one joint after another it may have been building up pressure inside from the heat. By letting it sit , what air was in the line dissipated so when you heated last joint there was enough empty pipe for the joint to take.

 

[rlitman]

Glad to hear you did it.

Just wondering this on your problem--
IF the pipe system is totally sealed, meaning no place for air to escape.
Could the air pressure (from heating the pipe) push out this last joint causing the solder not to flow?

It won't push the joint apart, but you may see steam escaping through the joint. That flow can push **** into the joint, which may prevent the solder from wetting all around. It certainly can make things more difficult.

 

[PelicanPines]

Glad to hear you did it.

Just wondering this on your problem--
IF the pipe system is totally sealed, meaning no place for air to escape.
Could the air pressure (from heating the pipe) push out this last joint causing the solder not to flow?

Funny you said that... My father did plumbing for an apartment building after he retired... he always taught me to open a "tap" when sweating pipes... to let the pressure out. Wonder if it was because he just had so much more experience than average or his OCD was kicking in.

 

[Dirtydan69]

I use propane but a professional Turbo Torch. Heats quite well. Water will do it. Boil it or bread.

 

[OccupantRJ]

Glad to hear you did it.

Just wondering this on your problem--
IF the pipe system is totally sealed, meaning no place for air to escape.
Could the air pressure (from heating the pipe) push out this last joint causing the solder not to flow?

Exactly what I was thinking.

 

[mobiledynamics]

map pro is only if I recall ...15% hotter than propane

 

[e36jon]

Continued thanks for the ruminations gang.

FWIW the line was open to atmosphere at both ends, with no water-plugs in the way, so building up air pressure was not the issue.

Something about old-house + ladder + open-flame doesn't make me want more heat! That said, this joint apparently needed everything propane had to offer, so maybe the 15% bump of MAP might have helped?

Cheers,

Jon