I am tring to connect new copper to an exist. residential copper water system. I cant get alll the water out of the existing water lines, so my soder joint fails. Is there some new way of dealing with this age old problem|? I tried to install a tee and union at the connection to the old system and the leak at the sodet joints, I have tried to drain the entire house by opening every faucet three times so far. I remember hearing about stuffing a piece of bread in the pipe. Does this really work? Is there some more advanced and more reliable method or is the old world approach valid? I appreciate any insite in to the subject… PS this is the first time I have loged on to the net. I hope this note dosnt just float in some hypertexrt black hole for the next 20 years.