I have just completed soldering all my copper joints and no there are no leaks to report! However, when sweating joints there were a couple of occasions where solder just wouldn't seem to flow so I quickly torched the solder directly just to get it flowing. On one occasion in particular with this method, the solder just seemed to blot on and around joint seem rather then quickly run into seem. As a result, some of my joints are not the neatest (then again, original builder's joints looked no better before renovation project).

Several days have now passed and there are no leaks. My thinking now is that it should be OK to sheet rock walls and tile. Of course there are no guarantees, but is it a probability that joints will continue to hold up for years to come?

I was working in real tight quarters and it was a MAJOR pain, time consuming, etc. thus I'm reluctant to pull apart and start again.

Rick

The heat temp matters a lot and the flux. If the joint was lacking flux and a clean fitting the Blot as you call it happens and won't flow well. If the joints were cleaned well the a quick torch away/ quick reflux / quick heat on to flow solder.

If you have low heat and low flux the flux dries a pinch before proper temp is reached for solder to flow.

Signed 21 Boat

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Just like 21Boat said: not enough flux or not hot enough.

If new sweat joints held regular household pressure for 3 days than you should be fine to cover up walls.

You may have also had some water inside the pipe which will keep the temp too low to solder. I would have redone the joint beore refilling the system, apply flame directly to the solder does not create a very good bond. Like Milo and 21 have said, clean copper and good flux with the absence of any water is the start to a good sweat fitting. In really tight or combustible areas I will sometimes just switch to a Sharkbite even though the cost is 10x more per fitting.

AAch if you run into a problem with moisture in a pipe use your torch back from the seat joint about 2 feet and get it hot enough to create steam. Then be ready to sweat the joint past that. It may take a couple of times. Heat attracts water and it will draw it in quantities. Of course the old bread trick jammed in pipe up the pipe can work must be quick to solder.

Another way when in tough tight places to solder. Pr tint the pipe you are join to solder the fitting to.

Clean/ flux/ solder all around the pipe wipe off when liquid hot with a dry rag. It should just look silvery. Now when you re flux and slip fitting on there is already solder on the whole one side of the joint. I pre tint big copper boiler lines so solder is flowing into solder. Less chance of voids.

Signed 21 Boat

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Also, plumbing supply houses sell Heat Shield Pads. You put the behind the pipe on stud and then you can solder away w/o fear of burning down your house...

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Originally Posted by 21boat

The heat temp matters a lot and the flux. If the joint was lacking flux and a clean fitting the Blot as you call it happens and won't flow well. If the joints were cleaned well the a quick torch away/ quick reflux / quick heat on to flow solder.

If you have low heat and low flux the flux dries a pinch before proper temp is reached for solder to flow.

Signed 21 Boat

If I Helped To Answer Your Question Please Rate My Answer

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Thanks for great feedback. I think it took a while for ball valve fittings (shut-off) which prompted flux to dry up a bit. However, I'm thinking there was enough flux to bond solder creating good enough seem - no matter how unsightly.

With pressure back up for over three days, still no leaks. Do you agree that its pretty likely that joints will hold up for years? I'm guessing if there were voids, they would show up in small leaks by now.

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Originally Posted by Milo Dolezal

Just like 21Boat said: not enough flux or not hot enough.

If new sweat joints held regular household pressure for 3 days than you should be fine to cover up walls.

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Thanks for great feedback.

On the couple of problem joints, I think it took a while to heat up ball valve fittings (shut off) which caused flux to dry up a little. However, there must have been just enough flux and heat for solder to bond.

With pressure back up for over three days and no leaks whatsoever, consensus indicates it should be OK for years to come.

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Originally Posted by ballengerb1

You may have also had some water inside the pipe which will keep the temp too low to solder. I would have redone the joint beore refilling the system, apply flame directly to the solder does not create a very good bond. Like Milo and 21 have said, clean copper and good flux with the absence of any water is the start to a good sweat fitting. In really tight or combustible areas I will sometimes just switch to a Sharkbite even though the cost is 10x more per fitting.

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When talking about quality of solder bonds, I'm hoping its as simple as determining weather joints leak or not when cooled and pressure returns. My biggest fear is that after putting walls back up and tiling, etc a leak develops at a problem joint somewhere down the road causing rip out of new bathroom.

On other hand, I'm hearing that if bond has held up to pressure for now three days running, its probably a safe bet it should be OK.

Thought you might like this video, should have given it to you days ago. When installing a ball valve its important to het the valve and not just the copper pipe. Soldering Copper Pipe with Ball Valves Video