How to Solder Copper Pipe

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Soldering copper pipe, commonly referred to as “sweating” pipe, is a job any homeowner can do. As with any home improvement or DIY project, it is important to understand the basic skills before starting. After a little planning and ensuring that you have the right tools on hand, soldering copper pipe should be simple. Join our host, Jeff Wilson, as we learn the basic skills required to make one of the most common connections in plumbing.

Necessary Tools

Before you begin, you need to make sure that you have the right tools for the job, including:

  • Pipe cutter
  • Half-round file
  • Steel brush
  • Abrasive paper
  • Water-soluble flux and flux brush
  • Lead-free solder
  • Propane torch (In our example, a self-igniting torch was used. If you are not using a self-igniting torch, you will also need a spark lighter. Never light a propane torch with matches or a lighter.)
  • Protective gloves and glasses

How to Solder Copper Pipe

Soldering copper pipe is a simple operation, but it’s important that you do it correctly so that you do not end up with any leaks.

  1. Place the pipe cutter on the copper pipe and tighten the handle. Rotate it around the pipe until it starts to loosen. Retighten the pipe cutter and continue to rotate it around the pipe. Repeat until the cutter wheel makes it through the pipe and it separates. Do this for both pieces of pipe that you will be joining.
  2. Use the half-rounded file to remove any burrs and the lip caused by cutting.
  3. Use the abrasive paper and polish the pipe ends and the steel brush to clean the inside of the fitting. When the copper pipe is shiny like a new penny, it is ready for soldering.
  4. Now the flux comes into play. Flux helps to keep the copper from oxidizing when it’s heated, which means that the solder can bond better with the copper. Apply flux to the pipe ends and to the inside of the fitting. Fit the pieces together and rotate them to make sure the flux is evenly distributed.
  5. Put on your protective gloves and glasses and light the propane torch. Center the flame on the fitting and heat the joint evenly. The tip of the light blue flame is the hottest part. Look for a greenish flame to tell you when the joint is ready for solder, or repeatedly touch the solder to the joint area to see if the copper is hot enough to melt the solder. Do not overheat.
  6. Once the joint is hot enough, quickly run the solder over the joint. You will notice the solder being pulled into the joint via capillary action. Make sure to fill the joint, but try not to overfill since solder can run down inside the pipe and restrict the flow of water.
Ryan Carpico

Ryan is a Registered Architect who earned a Bachelor of Architecture from the University of Kentucky in 1998. His experience in a broad spectrum of architectural projects includes design and project management in multi-family residential, general commercial, and institutional projects. This architectural experience is balanced with a background in general contracting of residential and light commercial construction projects. Ryan’s knowledge and ability as both architect and builder enable him to address both the technical and practical sides of the comprehensive body of construction knowledge.

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