The little shutoff valve for one of the toilets started leaking a few weeks ago. I didn't know the leak rate, so I put a plastic container under it and checked it every once in a while. I needed to empty it once/week, then once/day and while I had decided to change it from when the leak was first noticed; the once/day schedule pushed this job to the top of the "to do" list.
I picked-up a ball valve that worked by a tight fitting rubber sleeve which would go over the copper pipe. I had reservations but figured if the hardware store is full of these devices then it is not like buying from a TV infomercial.
I couldn't tell how the original valve was attached until I tried to remove it--it was soldered on. Great! If I have to bring the torch into play, I might as well have gotten a valve which solders on. When I finished, I turned on the water to the house and maybe it was leaking, couldn't be sure. So the plastic container went under the valve to patiently tell me what was what. It leaked at about the same rate as the original valve. Fine! I'd get a solder version the next Saturday.
The plan for Saturday was first, a group run from Hopkinton to Boston College, then I would get some McD's in Drum Hill then off to the Sear's one block away. Well, after the 21 miler I was sick from fatigue and so blew-off the double cheeseburger for $1.29 deal and went home.
This morning at 8:00 AM the valve blew and this was noticed by water flooding in from the ceiling of the laundry room--directly below the bathroom with the bad valve. Like I said at the top--a good bit of timing. It could have blown when nobody was home or in the middle of the night. The hardware stores were not open for another hour, so I soldered a cap over the feed pipe and then turned back on the water to the house. Everything was fine except for one toilet out of commission and there are two others available.
Later, at the hardware store, I had picked-out a new valve and asked the guys at the counter if I should take the valve apart before soldering it in. "No, don't mess with the seals" they said. I planned to ignore them: It can't be good for rubber O-rings to get exposed to the heat from a torch. It can be ameliorated by opening the valve, since then the rings are not pushed-up tightly against the hot metal, but still, why not avoid the whole problem? Indeed, when I got home and read (via magnifying glass) the micro-print on the package, it said to remove the valve stem before soldering.
The little end-cap that had saved breakfast, showers, breakfast cleanup & so forth; took back as much as it had saved. These copper pieces fit rather snugly. Not a problem when assembling a piece, since everything is cold. But when it comes to taking things apart, you have to heat until the solder is liquid and then use tools to do all of the manipulations. The end cap bound-up and I was never able to get it off. In the end, I redid everything from the wall to the toilet tank.
Done now and no leaks. My experience with copper and solder is that if it doesn't leak right away it will never leak.