I just had to replace both supply lines to my kitchen sink. (1/2" diameter copper pipe). After Doing all of the pipe soldering I turned the water back on to discover that the point where I mated the new copper pipe with the old copper pipe is leaking for both the hot and the cold water.

I know you're not supposed to solder when there's water in the pipes, but what should I do know? just try to resolder it?

Thanks
Jody

 

It's not that you aren't "supposed" to resolder when there is water in the pipes, it's that YOU CAN'T!! The water in the pipes won't allow you to get the pipes hot enough to melt the solder! Drain the water from the pipes before you resolder the joints. And make sure you clean the pipes thoroughly, and use clean flux.

 

You could just retry it. One thing to remember. Heat make water expand. Copper is a very good conductor of heat. Steam causes leaks. So it you retry it get as much water out as possible. This can be done by opening a faucett if there is one that is lower than the kitchen sink. Also use a good torch acetlene or mapp gas they are much hotter than propane.

 

All the heat in the world won't help you if you have water in the pipes. If all else fails and you can't get the water out of the pipes. stuff some bread into the pipes. This will keep the water out of the way long enough for you to solder the joint. Once you has a good solder joint and it has cooled, turn on the water and open the valve. The bread will flush out of the valve.

 

Thanks for the information. I did the resolder, and it appeared to work for the minute or so that a couple other pipes held. I had hoped that the other pipe work was ok when I fixed these pipes, but obviously it wasn't. So, I tried patching things up, but it was a watery mess. I've decided to give up and start again fresh tomorrow. This time I'm going to replumb the whole kit and kaboodle.

The house I have was very poorly redone by someone what appears to be ~15 years ago. When they ran the lines, they used the same 1/2" supply line for the bathroom and the kitchen, and hobbled the plumbing together from what was probably spare parts. The two pieces I'm most worried about are the primary supply line, which runs through the attic and then down through the wall, and the feeder lines to the bathroom sink, which run willy nilly (and vaguely horizontally) through the walls/cabinets. Any tips on hos to make sure these two pipes are as dry as possible?

Thanks for all your help
Jody

 

I'm still learning, but what I have done the others have already mentioned...open a lower valve (faucet..usually the one outside), and sticking bread in the pipe...you have to be ready to solder when you do this as the bread won't last forever. Another method I have used is a shop vac. It worked pretty well in conjunction with everything else.

 

Well,

Ok things are going well now, after sitting back, reexamining the situation, and taking everyone's advice. I was a bit smarter today, and stopped by the hardware store and picked up a couple of those rubber plugs for testing water. I've now fixed all but the last 90 degree elbow joint. I'm just waiting for the last of the water to drain out of my latest test. Here's a nice trick I figured out this morning while trying to drain the plumbing system. If any of the pipe is below the lowest point from which any faucets will drain, just select an easily replaceable part (I chose elbow joints) and drill a hole in it. It's a fairly quick/clean way to drain the pipe.

But, I now have another question. While testing the pipes my cold water came through beautifully, but the hot water barely trickled, Is this a bad thing? or is it just that some sort of vaccuum needs to build up in the hot water pipe so it'll start flowing.

Again, thanks for the help

Jody

 

Well, it's all fixed now. Thanks to everyone for their advice.

Jody