Learn to sweat a pipe properly and you can save some bucks by doing simple plumbing repairs yourself. Just make sure your joint starts with clean pipes (no water or grit inside).
1) Deburr inside the pipe ends with a reamer, then polish the outside with an emery cloth.
2) Coat both parts with flux and fit them together—wherever the flux is, the solder will flow.
3) Hold a propane torch flame on one side of the joint. When the flux bubbles, touch the solder to the other side of the joint and move the flame away. The solder will be sucked all around the fitting. "The heat draws the solder toward the hottest point," says Richard Trethewey.
4) Immediately wipe the joint with a damp rag. New joint, no sweat.