If you are trying to do some repairs on your old copper water pipe, you may become increasingly frustrated at the problems which soldered joins are causing you. In the past, a straight solder of copper water pipe parts was the only way to keep water pipes leak-free, but they can sometimes become corroded, or galvanized together. If your copper water pipe is also joined to a different metal, then this can increase the likelihood that the pipe is stuck in the solder forever. Before you take a chainsaw to the pipe, there are other ways in which you can remove a soldered copper water pipe without causing too much damage.
Step 1 - Turn off the Water Supply
Before you take any action which involves the plumbing in your home, you should turn off the water supply to that area. In most cases, you can simply shut off the water to a room, or a part of the house, but if you are working on outside pipes, or those which connect to the whole of the house, then you would be better to shut off the main water supply valve, using your wrench to turn the valve if it is stiff. You should then run taps in both the upstairs and downstairs of the home in order to ensure that you have completely emptied the water pipes.
Step 2 - Try To Melt the Solder
One way to proceed with removing the old copper water pipes is to try and melt the solder. Use your blow torch, and warm up the pipes from underneath. You will need to use safety gloves and goggles while doing this part of the operation, and if at any point you are worried about the state of the metal, stop using the blow torch immediately. Take care not to heat up copper water pipes in the vicinity of wooden beams, insulation, electrical wiring, or other flammable items.
Step 4 - Twist the Pipes
Once the pipes have been heated a little, take the pipe in your locking pliers, and twist the fittings. You may be able to encourage them to fall apart by striking the fittings with your mallet, or by locking the pliers, and then basically driving them around using the hammer. Do not hit the pipes directly, although you can use a mallet to gently nudge the fittings.
Step 5 - Use Sandpaper
If all else fails, you can try removing the solder from your old copper pipes by rubbing it with some sandpaper. Try using a solvent on the surface of the sandpaper, or simply use a coarse grain to grind away the metal solder. Once you start loosening the pipes, you may find that they come away easily, or you may apply the sandpaper, and then shift the pipes using the locking pliers and the hammer.