How to tell if a solder joint is good

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Travis K

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Hi everyone. In the past 20 years I have had only 1 call back on a bad solder joint. I am a general contractor and don't do much solder work anymore but I always worry about the soundness of a soldered joint.
Most of the time the capillary effect shows itself and I can clearly see the solder getting sucked in to the joint but on occasion the solder just appears to bead up on the lip of the fitting. This happened on 1 joint on my current remodel.
I used tinning Flux on these and I feel confident of all the joints except this one. It's a straight coupler that has the original pipe below it and a new short section going up to a 90 that then tapers to 1/2 inch and to a pex adapter. The bottom side of the coupler looks great and sucked in plenty of solder. The upper part never really felt like it flowed right. I did work from bottom up and am hoping that it sucked in plenty of solder and it's fine.
After it cooled for an hour I hooked up the pex and turned the water back on. I gave the coupler a few taps with a wrench to see if I could get it to spring a leak. It didn't.

I am getting ready to cover the wall with sheet rock and it will be covered with a tile wainscoting. I don't want this to leak.
Should I consider it good? Is there another way to test it? Or should I redo the section with new pipe? I do feel like I properly cleaned and fluxed the work before getting started.
Thoughts?
Travis

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Reach4

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Top one may be fine-- not sure. Bottom one does not look good.

I don't know how it got that way. Pipe and fitting not cleaned well enough? Not hot enough? Not fluxed well?

Tinning flux make things solder better usually.
 

James Henry

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ragged solder is a sign of pipe or fitting not hot enough. its to bad the PEX is hooked up, because it is a new joint you could have reheated it and reapplied flux and solder.
 

Travis K

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Thanks for the replies. The joint in question is the top side of the coupler. I am confident of the other joints. They might not be the cleanest finished products but I know that they have good coverage.
I can turn off the water and redo it if needed. It's a little hassle but not that bad conducting the possible alternative.
Speaking of which. Look at this whole job and tell me what I could have done better. I am responsible for connecting the PEX and running out through the slab. So basically everything except the abs. I wish that I could have gotten away with not using the PEX 90. The pipe kept kinking.

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Travis K

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Another question since I have your attention.
What's this second pipe that was buried under this shower and uncovered during the tear out? It's the ABS pipe on the right with the light colored Fernco. It was just below the surface, capped with the rubber cap and covered with cement. I assume that it was a screw up during rough plumbing.
And also when roughing in a shower valve. I am lucky that there wasn't a stud running right up the middle of this wall but what's your favorite way to hang the valve. This is the first time doing it this way. It's been more work drilling the holes for the vent pipe but I had the pipe disconnected so I figured why not.
Thanks in advance

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JohnCT

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Most of the time the capillary effect shows itself and I can clearly see the solder getting sucked in to the joint but on occasion the solder just appears to bead up on the lip of the fitting. This happened on 1 joint on my current remodel.

I'm not a pro, but I wouldn't trust that joint. On a proper joint, the solder should never bead up on the lip of the fitting. When everything goes according to plan, the solder should literally disappear into the joint as you apply it and the solder will literally run around the full circle. This guarantees that the entire interior surface of the joint has been wetted with solder. If it beads on the lip and doesn't want to get sucked in, it still might be water tight now but any flexing of the pipe in the future could cause a leak.

If it was in an exposed area, then I wouldn't sweat it (yep), but if it's going to be 'rocked over, I'd make sure that joint was perfect.

John
 

Reach4

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It seems possible that could have a good joint under it, but the person kept jabbing solder at the joint during the cooling process.
 

JohnCT

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Don't shoot the messenger, but if that's Uponor red PEX, I'd replace it before you sheetrock. There have been several threads on this site about the Uponor (only) color PEX process damaging the underlying PEX causing splits and leaks in only a few years. If it's someone else's colored PEX, carry on.

John
 

Travis K

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Thanks for the replies. I ended up changing the copper section in question.
I cut the old coupler apart and it did appear to be a good weld.
As for the colored uponor. Hmm, I will research it and maybe go pick up a section of the clear uponor.
I think that I want to also remove the plastic 90 degree fitting also. I feel like there is too much angular pressure on the 90 and might would replace it with a brass 90 if I can't get the pipe to bend.
Any suggestions? Here's the new solder joint.

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JohnCT

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That looks great. Even though your previous joint had good penetration, I'm sure you'll sleep better knowing for sure it's perfect.

The plastic EP fittings are very very tough and I wouldn't worry about it from a stress standpoint.

John
 
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