Welding, brazing, and soldering are the three methods creating a sealed connection between copper pipes. The intense amount of heat needed to weld copper pipes makes it difficult to perform outside of a controlled shop environment. Brazing, like welding, requires a high amount of heat, and is used on pressurized copper refrigeration lines. Soldering requires the least amount of heat, provides a water tight seal and is the standard connection used for residential copper water supply lines.
Tear a piece of emery cloth to twice as long as the diameter of your copper pipe.Wrap the emery cloth around one end of a copper pipe. Pinch the loose ends of the emery cloth together.
Hold the emery cloth in place with one hand. Twist the copper pipe back and forth with your other hand.
Remove the emery cloth from the copper pipe. Examine the pipe's end. If it is shiny, place the length of copper pipe aside, and repeat steps two, three and four with the other length of copper pipe.Insert a pipe brush into one end of the coupling.
Twist the brush inside the coupling. Remove the brush and check the inside of the coupling to see if it is shiny. Repeat until it is shiny.Rotate the coupling and repeat the interior cleaning on the other end of the coupling.
Apply flux to the entire inside of the coupling with the flux brush.Load both outside clean surfaces of the copper pipes with flux. Do not touch the cleaned ends of the copper pipes. The oil from your fingers will interfere with the flow of the solder.
Slide the coupling onto the cleaned and fluxed end of one of the copper pipes. Insert the other cleaned and fluxed pipe into the empty side of the coupling.Straighten 12-inches of solder. Bend the last three inches of solder to a 90-degree angle.
Turn on the torch. Ignite the torch with the built-in igniter or a striker. Do not use matches or a lighter to ignite your torch, as this could creates a burn hazard.Place the torch's flame on the center of the copper coupling.
Distribute the heat evenly around the coupling. Do not apply heat near the edges of the coupling.
Bump the solder against the edge of the coupling. When the solder draws into the coupling, run solder around the edges on both sides of the coupling.
Wipe around the coupling with the wet rag to clear excess solder from the joint.Allow the connection to cool completely before handling the pipe.