Sweating old sweat joint?


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Old 07-31-12, 07:13 AM
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Question Sweating old sweat joint?

Can I RE-SWEAT a older copper elbow that is spraying a fine stream? I cut the pipe approx. 6" away from this elbow, and added a new downward elbow yesterday, and over night the elbow I didn't sweat started to leak. I am guessing the heat from the new sweat joint caused the problem.

I used LEAD-FREE solder, it seemed to require a lot more heat than LEAD solder I have used in the past.

Can I heat the leaking elbow and re-solder with LEAD based solder?

Needless to say I will have water OUT of the pipes.

Thank You,

Dale in Indy
 
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Old 07-31-12, 07:56 AM
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Dale, I moved your thread from Water softener forum to the main plumbing/pipe forum.
 
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Old 07-31-12, 08:27 AM
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Don't use lead based solder if the water lines are used for drinking.

Mapp gas is preferred because its hotter then propane for homeowner use. Its the one in the yellow bottle if your using a handheld torch.

The trick to re-soldering a joint is to actually take it apart and clean it up, re flux and solder.

If you are experienced you can simply re heat the joint and hit it with flux and re-solder. The trouble there is you need a open area to release the steam produced. You will never be able to re-solder it.

Often a bleeder screw on a valve loosened works. if I remove the stem on a nearby valve altogether works even better.
 
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Old 07-31-12, 09:39 AM
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Sweet fitting.

The pipe in question is after the shut off valve, and one end is open, so steam etc. can escape.

I will use my Mapp gas torch this time, and will stick with LEAD FREE solder.

Thank You,

Dale in Indy
 
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Old 07-31-12, 10:46 AM
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MAPP will allow you to solder the joint quicker but I still wrap a wet rag around joints nearby when I'm sweating a fitting.
 
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Old 07-31-12, 11:05 AM
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Good thought, I wondered about protecting nearby joints.

Thank You,

Dale in Indy
 
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Old 08-02-12, 08:52 PM
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Still having an issue.,

I have two (2) vertical 3/4" copper pipes coming up out of the floor. The two pipes are joined by a horizonal cross over pipe, and above each vertical and above the cross over by-pass is a shut off valve. Coming out the top of the valves is a 8" piece of copper that is the inlet pipe, and the other is the return pipe. This is where I am trying to sweat 90 degree elbows with a 2" long copper stub that my PUSH ON stainless line to the softener needs to connect.

I clean the copper with emery stips, wipe off any grit, brush on flux, clean the inside of my fittings with steel wool, wipe clean, wipe on flux, then push on and ready for my torch and LEAD FREE SOLDER.

It takes forever for the fittings to get hot enough to melt the solder, and then the solder doesn't flow or enter the fittings and seal. There is water in the vertical portions of the pipe, but approx. 4" from my fittings. Should I SUCK the water out above the valve, or use bread dough to dam it off?

I have sweated copper dozens of times, and no issues before. I feel like a complete dud....

Comments are most welcome,

Dale in Indy
 
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Old 08-02-12, 10:34 PM
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What kind of flux?

What type of torch?

How are you wiping clean the fitting before using flux?

Is there water in the line your soldering? Even if there is some trickle through then its enough to cool it that will be hard to solder.

Some home store fluxes are bad to use. The white stuff in particular.
 
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Old 08-03-12, 06:53 AM
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Post #7 above tells you a lot about my setup.

I have a Propane, and a Mapp torches. Both put out a good flame.

My flux is part of a two part package. The flux is dark gray semi-paste, NON-LEAD. It is made by OATEY, it is their (safe flo silver lead free plumbing soldering kit. I also have liquid flux by ALPHA METALS.

The solder says it works just like 50-50 tin & lead solder.

In reading my # 7 post you will learn there is water in the VERTICAL pipe, but NONE in the 6-8" horizontal piece I want to sweat my fittings to.

Thanks,

Dale in Indy
 
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Old 08-03-12, 07:07 AM
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The only reason solder would not flow is from water or overheating the pipe that the flux burns off. You need to clean the pipe and fitting and apply flux to both surfaces.

Dont touch the cleaned fittings with your fingers. The oils from your hands could cause leaks.

Now there are a lot of variables to what you are exactly doing.

I have sweated copper dozens of times, and no issues before. I feel like a complete dud....


You have done this before so you have some experience. I would say from your post its a water issue. Did you take the fitting apart to clean it up again, and did you notice water come out of the pipe?

 
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Old 08-03-12, 07:34 AM
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I cleaned the pipe fittings, and the pipe, I wipe on flux, I DON'T TOUCH after such.

I will suck out the water above the pipe valve in the vertical piece. This way I know that NO water is in the pipe I am sweating.

I think it is either steam, or to much heat. I will practice on some scraps this morning.

Dale in Indy
 
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Old 08-03-12, 07:53 AM
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I just did a couple test fittings away from the actual project, and all worked great, so I will review the water in the line issue.

Dale in Indy
 
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Old 08-03-12, 08:25 AM
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OK let us know.

I know it can be frustrating. Been there done that many times.
 
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Old 08-03-12, 02:11 PM
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Ok, what I found was this.....

The pipe went VERTICAL approx. 6" above the shut off valve. Then HORIZONTAL approx. 6", water wasn't present in the horizontal pipe, but when I looked inside I could see water at the top of the vertical pipe and elbow. I twisted a cloth, I fed it in with a twisting motion and the rag soaked up the water as a wick would do. I did this a couple times, and soon the rag was dry.

I then tried sweating again, and it worked like a charm.

The torch was casing the water to boil, and steam prevented the soldering process.

Dale in Indy
 
 

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