When will my sweat joints leak?

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Hackney plumbing

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Hmmm ... I suppose the air in the pipe has already expanded by the time you apply the solder.

BINGO

Basic gas laws...PV=nrT, or if you move things around P=constant*T. Increase T, increase pressure. Which gas affects which constant you use, but just like a hot air balloon rises because the air expands, it will increase pressure in a pipe if it is closed. the smaller the pipe, the hotter the whole thing gets, the higher you can get the pressure. Yes, water when it turns to steam is also an issue, but even steam increases pressure as you raise it's temperature; it's just that it expands radically when it goes from liquid to vapor, which adds to the overall problem. Basic first year chemistry...

Generally, it's fairly easy to leave an end open. If you don't, the joint is at risk. Obviously, it may not get high enough all the time, but there are times when it will give you grief.

We can argue forever,you can take my word for it....or I can make you a video and prove it. Take your pick.

I'll take a piece of 1/2" about a 12" long....and solder caps on each end......Would that prove it to you? Tell me how I can prove it to you and I'll do my best.
 
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Terry

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When I was the plumbing supervisor at Merit Mechanical, I had under me a commercial plumber that thought the same way as Hackney. It was brand new 2" copper pipe and fittings. No moisture at all. I insisted that he prop the check valve open while he soldered.

He insisted that I was wrong, and that the pipe was large enough to solder that way.

I tried to explain to him that the heated air would blow a hole in the last joint soldered.

Well, he had the last laugh on me. I did it his way, and when we turned the water back on for the retirement home, the last joint leaked.The the nursing staff and old people in the home started asking why we were shutting down again. What a friggin waste of time. We had the building shut down two more hours while we did a full drain down, took out the section of leaking pipe, disassembled it and re-soldered it. We had four plumbers on the job, and eighty people waiting on the water. What a huge, stupid mistake.

Yes folks, it's that simple. Hot air expands and it has to go somewhere. Molten solder is no match for it. I've been plumbing since 1974, not nearly as long as hj, and we both know you can't fool mother nature. Hot air will always expand. That's how hot air balloons work too. Expanded hot air. Duh!
 

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Hackney plumbing

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When I was the plumbing supervisor at Merit Mechanical, I had under me a commercial plumber that thought the same way as Hackney.

It was brand new 2" copper pipe and fittings. No moisture at all. I insisted that he prop the check valve open while he soldered.

He insisted that I was wrong, and that the pipe was large enough to solder that way. I tried to explain to him that the heated air would blow a hole in the last joint soldered. Well, he had the last laugh on me. I did it his way, and when we turned the water back on for the retirement home, the last joint leaked.
The the nursing staff and old people in the home started asking why we were shutting down again.

What a friggin waste of time. We had the building shut down two more hours while we did a full drain down, took out the section of leaking pipe, disassembled it and re-soldered it. We had four plumbers on the job, and eighty people waiting on the water. What a huge, stupid mistake.

Yes folks, it's that simple. Hot air expands and it has to go somewhere. Molten solder is no match for it. I've been plumbing since 1974, not nearly as long as hj, and we both know you can't fool mother nature. Hot air will always expand. That's how hot air balloons work too. Expanded hot air. Duh!

The joints not air tight until the solder cools by the time I apply the solder the pipe is actually cooling off.. As the air expands it escapes from the joint.

I'll make the video if you'll let me post it and put this to bed.
 

Terry

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It doesn't matter if you can make one joint work that way. I've replaced dozens of bad joints.

The fellow soldering the 2" fittings thought he was doing it right too.

What have you got against opening up a valve?

But go ahead, take a 12" long stick of copper and solder two caps on it. I would love to see video of that.
 

Hackney plumbing

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It doesn't matter if you can make one joint work that way. I've replaced dozens of bad joints.

The fellow soldering the 2" fittings thought he was doing it right too.

We have homes on concrete slabs here.....people want to remodel so I cap off the lines to a fixture. The copper loops up from the slab and its holding water. Still with me? Ok so I cut the copper stub off and blow some water out,enough that its now well below the 90 degree ell looking out of the wall. Solder the cap on.

It doesn't leak then and it will not leak later because its a good joint. I've removed them and checked for full coverage.

I'll do the same in the video.

Physics wouldn;t alllow me to make one joint if things worked like you guys are saying. It would be inpossible to make a good joint period. Thats just not so.
 
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Terry

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No...........I want to see it on a 12" section of copper pipe.

If I don't see the entire pipe, I will assume you opened up a faucet.

Or that you have a leaking toilet fill valve.
 

Hackney plumbing

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No...........I want to see it on a 12" section of copper pipe.

If I don't see the entire pipe, I will assume you opened up a faucet.

Or that you have a leaking toilet fill valve.

No problem a 12" piece of 1/2". I'll set it up on a bench and you will be able to see the entire pipe and both caps....everything. Give me a little while...I ran 7 service calls today and haven't had dinner.

UPDATE: I'm uploading the video now. Actually its two videos,one soldering the caps and one video of the water test in my kitchen sink.
 
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Terry

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There's no way to know if you have a leak though, without hooking that up to something.

A pin hole leak is never obvious
 
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Hackney plumbing

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There's no way to know if you have a leak though, without hooking that up to something.

So how about I cut the pipe in half and install a tee and pressure it up? On another video for sure. I could take the caps off and take pics?

Gp try it some day and you will see there is absolutely no spitting and sputtering of the solder as you make the joints.

How about I cut the joint in several pieces vertically? That would allow you to see the coverage.


My friend has a hydrostatic test pump that will pump to failure of the pipe and or fitting. They use it to test hydraulic hoses. I will see if they are not too busy and maybe I can make it happen.
 
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Dlarrivee

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Wow.

So the two links show the exact same video, a chunk of pipe with two caps on it, and no way of proving that there isn't a pin-hole in either of them.
 

Hackney plumbing

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Wow.

So the two links show the exact same video, a chunk of pipe with two caps on it, and no way of proving that there isn't a pin-hole in either of them.

You know that last video is the pipe being placed in water. Rumor has it that if it had a pinhole in the solder joint it would blow bubbles when submerged. Now thats just a rumor.......I cant prove it.
 

Hackney plumbing

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Fix the links in your post, they are both the same.
Sorry about that.....it shows the water test now.

I'm almost positive I could take it and have it tested to failure.....depends on how much testing their doing. I think he said it can develop 100,000 psi or more. They will use hydraulic fluid for the test.
 

Dlarrivee

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What did you use to do the bend on that 1/2"?

Whoever did the water lines in my house in 1975 used something to bend offsets all over the place...
 

Hackney plumbing

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What did you use to do the bend on that 1/2"?

Whoever did the water lines in my house in 1975 used something to bend offsets all over the place...

That came off a roll,I just measured out 12" and cut it. I have a Ridgid bender tho that will bend 1/2" i.d 5/8" o.d copper. I love it,picked it up off **** and it still looked new.
 

Hackney plumbing

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The two caps I soldered on the 12" piece of copper will be tested to failure. I'm going to cut the pipe in half and have each piece tested until the joints blows or the pipe blows. That is 1/2" type L soft copper. I will have to solder on fittings to connect to the test pump.

I'm not sure how the test chamber is set up but if I can video the test I will. At the very least I will take pics of the results. I'm curous as to what it can hold.

I will get around to doing it in the next week or so and post the results.......no matter what the results are.
 

BobL43

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Hmm

It doesn't matter if you can make one joint work that way. I've replaced dozens of bad joints.

The fellow soldering the 2" fittings thought he was doing it right too.

What have you got against opening up a valve?

But go ahead, take a 12" long stick of copper and solder two caps on it. I would love to see video of that.

another video that seems apropo here;) :http://www.youtube.com/watch?v=4sA1c1WErUk

and they're still good friends, I guess
 

Ballvalve

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Be more fun if those rams had Carhart jackets on.

Didnt look like much solder on those caps. I'll bet you dont get 200 psi. What flavor solder?

Try a second one with some liquid left inside for a comp.

While you are at it, do one with copper epoxy on the caps and run the pressure test. That would be damn interesting.

Dont need the hydraulics, any 2 stage compressor has 200 to 250 psi at the tank.
 
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