Need your help installing a shutoff valve! HELP! HELP!
Please don't install a compression fitting shut off valve on that copper line. If you do, you'll be crimping a brass ferrule onto that pipe, and you won't be able to remove it.
If I were you, I would start by removing the toilet tank only. Shut off the water to the tank and use a mirror and flashlight to check the condition of the tank-to-bowl bolts holding the tank to the bowl. It's very possible that some monkey used steel bolts or steel nuts here, and the nuts are rusted on so badly that you simply can't remove the tank-to-bowl bolts. In that case, you'll have to remove the plastic bolts that hold the toilet seat on and spend an evening cutting through the tank-to-bowl bolts with a hack saw blade slipped between tank and bowl. Maybe flush the toilet to drain most of the water out of the tank, and dip or sponge out the rest.
Once you cut through the tank-to-bowl bolts (or unscrew them normally), then it's just a matter of cutting that copper pipe with a pipe cutter to remove the tank. I'd cut it fairly low, close to the elbow, and then just use a short piece of small diameter tubing to siphon the water out of that copper piping (or cut the pipe gain on the horizontal side of the elbow to allow the water to drain out of the piping. If you're cutting with a hack saw, cut from the bottom as you only need a hole for the water to drain out.
Then, fold up a small piece of cloth or paper towel until it's only about an inch wide, soak it in water, squeeze it out a bit so it's wet, but not dripping and wrap it around that pipe just between the escutcheon plate and the copper coupling. That will keep the pipe cool so that you don't inadvertantly unsolder the short pipe from a tee inside the wall.
With the wet towel in place keeping the pipe cool, put a leather glove on and heat that coupling. Apply a twisting force to the end of the pipe and you'll probably see the solder melt on that coupling. Soon afterwards the pipe will come loose from the coupling or the coupling will come loose from the short pipe. If the coupling doesn't come off, grab it with a pair of pliers and pull it off too. Then, as everyone else mentioned, wipe the molten solder off the end of that short pipe. You want to do this quickly before the solder re-solidifies.
Then, I'd solder a Brass Craft compression stop on. The advantage of a standard Brasscraft stop is that you can remove the spindle from it to allow water to drain out of the pipe in future. You can't do that with the new quarter turn style ball valve stops. With the tank off, you should have reasonably good access to that piping with a soldering torch.
Then, I'd probably replace any old brass you have in your toilet tank with a Fluidmaster A400 ballcock and a Crane-style flush valve. Use a new tank-to-bowl washer and a Fluidmaster braided stainless steel flexitube to connect the A400 ballcock to the Brasscraft stop.
Also, check any toilet tank-to-bowl bolts with a magnet. Brass is non-magnetic, so don't use any bolts that exhibit any magnetism. Check that the nuts and washers you use on those bolts are non-magnetic too.
PS: What kind of torch are you using. Since you're starting to do DIY work, you should have a proper torch. You want a torch that mixes the propane and air in a short mixing tube before it ignites that mixture. This is the basic principle of the Bunsen burner. The fact that the fuel and air are pre mixed means the flame can burn much more rapidly and therefore much hotter than a cheap torch that doesn't premix the fuel and air. You want that hotter flame because it allows you to concentrate the heat where you want it. With a cheap torch that doesn't premix the fuel and air, the flame temperature is lower and so the heat spreads through the piping more before you can get any soldering or unsoldering done.
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Last edited by Nestor_Kelebay; 12-16-2008 at 08:00 PM.