Copper pipe soldering is not as technical as soldering an electronics component onto a printed circuit board, but it is potentially more dangerous, can cause burns and even fires. To know how to solder copper pipe safely and effectively, you will need to know important soldering techniques such as those below.
Tarnish (oxidation) on a copper pipe can prevent a solid bond that would otherwise be made between copper and solder. Polishing a copper pipe's outside surface with emery cloth and inside surface with a brush to make them shine like a new penny will better ensure a good bond.
Another key to achieving a good bond between copper and solder is the use of a flux that further cleans the copper surface, removing tarnish, and etching the copper surface.
Using a Butane Torch
It is important when heating a copper pipe with a butane torch that the heat is distributed evenly along the pipe. This is done more effectively when the torch flame is kept moving along the pipe surface, with the blue tip of the flame touching the pipe surface.
Soldering a Fitting
Because the high end of a fitting will retain heat longer, it should be heated first, then the low end.