On Sunday I had to also cap a hot and cold line that originally fed the sauna (even though it was a 'dry sauna.' I guess they used it to hose down the floor?) The original plan (about a month ago) was to shut off the water and cut the lines with the sawzall and solder the caps on. Should have taken about 45 minutes tops. What really happened was that since the two lines were actually the lowest lines in the house, (lower than the faucet in the adjoining bathroom), they would not drain and as a result, no matter how much I drained them, there was still a slight trickle of water dripping out. Which resulted in a problem for soldering: if there is any quantity of water in the line, the pipe will not get hot enough as the water is absorbing the heat from the torch. To complicate matters, about 1" away was an ABS pipe for the trap which runs parallel to the line, which I had to carefully protect when using the torch. After trying several times, I could never get the pipes hot enough. What to do next? I couldn't leave the water in the house off for a few days. Off to the Home Depot as I had to temporarily buy some compression fittings to allow me to turn the water back on in the house and figure out possible solutions. I asked the plumbing guys what the problem was and they explained the water thing and suggested I drain the pipes. When I told them that this was the lowest thing in the house they suggested I cut the supply, just after the meter (!) and install a drain valve from which I could bleed the lines. Seemed like a lot of work to cap two lines! So my next step was to search the Internet for something that could help. After a bit of Googling, I found this product: Just for Copper. It is a liquid (non-toxic) which bonds copper to copper. So I ordered some and after a test, tried it out on the weekend. You just have to sand both pieces of the joint and then apply to both surfaces, twist on and, it worked. So far so good.