This Instructable shows how to use white bread and standard pipe sweating techniques to repair a leaking copper pipe. There are a ton of excellent instructions online and here at Instructables for pipe sweating, this isn't meant to replace those, but rather to show a trick I learned over a decade ago for sweating a pipe that is actively leaking. Normally you hope that by cutting off your mains and draining your lines you can eliminate any water leaking from the pipe you're trying to sweat. Sometimes you can get any extra out by using a shop vac. But sometimes you're screwed and a persistent drip will make it nearly impossible to do a proper solder because boiling water coming through a seam doesn't allow for the solder to set where it should. This is a cheap work around. There are commercial products that produce a similar result, usually wax plugs or other things that melt away as you sweat. That might work, but I have to imagine some wax is left behind because by the time you turn the water back on the wax won't be liquid anymore, but I digress.
I apologize if my pictures are a little dark or blurry. I had to do this in the dark while it was raining on my back, but we don't usually get to pick when these things happen, so I'm just glad I remembered to take photos at all.
Tools and Materials:
Couplers (correct diameter)
Extra length of pipe (correct diameter)
Non Lead Solder