How To Solder Copper Pipes. Soldering copper pipes is a common plumbing technique used to join two pieces of copper pipe together. Here are the steps for soldering copper pipes: 1. Cut the copper pipes: Use a pipe cutter or hacksaw to cut the copper pipes to the desired length. Make sure the ends of the pipes are clean and free from any burrs or debris. 2. Clean the pipes: Use a wire brush or sandpaper to clean the ends of the pipes and remove any oxidation or debris. The pipes must be clean and