Question on Soldering Copper Pipe

[Tidybuoy]

I have one tight spot where I have to solder a copper elbow for my new plumbing (part of my kitchen remodel).

My initial thought was to solder on one end while I have the complete pipe free (i.e., solder out in the driveway), then bring the pipe under the house and solder onto it's connecting pipe.

My concern: will heating up the pipe for the second solder, affect the first end of the elbow. (i.e., is it better to solder the whole elbow at one time or solder separately). Hope that makes sense...

[GH85Carrera]

I am not even remotely an expert on it however....

I always sand or wire brush the pipe to make it raw copper and then wire brush the inside of the joint, then apply flux to the pipe, and push it into the joint, and rotate. Then apply the torch, and solder when the flux is bubbling. It does not take much solder to wick into the joint and then a dab more solder to make a stronger joint.

[craigster59]

The flux in the first solder should hold the joint while you do the second side. The only suggestions I would make would be to make sure your valve is open in the line to prevent heat buildup which can mess up your joints and to use a heat shield that you can tack up to protect any studs or joists.

[908/930]

For an elbow better to solder both ends at the same time, the heat will likely disturb the first solder joint. clean then properly flux. Not saying it can't be done if you must.

[Tidybuoy]

Originally Posted by 908/930

For an elbow better to solder both ends at the same time, the heat will likely disturb the first solder joint. clean then properly flux. Not saying it can't be done if you must.

Thinking this thru, if I remove one floor board, I will have much better access. I'm going to go that route and solder both joints at the same time. One new board is cheap insurance against a plumbing leak due to a bad solder.

[flatbutt]

What I've done inthe past is to tin both sides of pipe before putting the joint in place. Then press the joint into place and heat while re-applying fluxed solder.

[908/930]

Removing floor board sounds like a good plan. When I have soldered near wood I usually have lightly sprayed it with water and always had a pail of water nearby and or an extinguisher. I have caught enough things on fire from soldering and welding, like to be prepared.

[Bill Douglas]

Usually soldering the second joint doesn't effect the first joint unless you put excessive heat into it.

[look 171]

We do it all the time. Solder one end, insert into tight space, then do the other. Just make sure there's no vibration so loosen the first joint. If heater enough, it will melt then solidify again. You should be good there but we try to not heat it that much, just enough for the second joint to do its job.

[Bill Douglas]

Vern, in this country we braze all out copper plumbing joints. Stronger and doesn't leach lead into your drinking water. I use a brazing rod called Sil-Fos and a Map gas torch.

[908/930]

Sil-Fos interesting, yes that would be a strong joint, would really confuse a plumber later when trying to remove. Have never herd of using that for water lines, more for refrigerant lines. That would be well in a situation like this though, braze the first joint and no worry of disturbing it while soldering the second joint.

[Bill Douglas]

I think Europe brazes copper plumbing pipes too. Sil-Fos is my choice, and commonly used amongst plumbers too. I guess some use the cheaper stuff that you dip the end of the brazing rod in flux. I like Sil-Fos because I give the pipes a quick scrub with a Scot-brite then go.

[look 171]

Originally Posted by Bill Douglas

I think Europe brazes copper plumbing pipes too. Sil-Fos is my choice, and commonly used amongst plumbers too. I guess some use the cheaper stuff that you dip the end of the brazing rod in flux. I like Sil-Fos because I give the pipes a quick scrub with a Scot-brite then go.

HVAc guys use that around here.

[drcoastline]

It will depend on the length of the pipe. If the piece is more than a few inches long you should be just fine, it shouldn't have any effect.

[drcoastline]

Originally Posted by Tidybuoy

Thinking this thru, if I remove one floor board, I will have much better access. I'm going to go that route and solder both joints at the same time. One new board is cheap insurance against a plumbing leak due to a bad solder.

You will know the bad sweat joint instantly. It either will leak or it won't

[porsche930dude]

You can use a sharkbite fitting they work very well

[Brian 162]

I've done what you did many times. The heat blanket and water spray bottle is excellent advice. Just try to keep the heat away from the joint you already soldered.

[Bugsinrugs]

Water spray bottle is a must. I’m think I’m going to use pex on my next remodel. Invest in some new tools.

[onewhippedpuppy]

Can you use a Shark Bite fitting? They are awesome for repairs in tight spaces.

[wdfifteen]

Originally Posted by Bill Douglas

Usually soldering the second joint doesn't effect the first joint unless you put excessive heat into it.

+!
Also make sure there is no stress on the first joint, either tension or torsion, so if the solder does soften in the joint it doesn't move and the solder just re-sets.