How to Solder Copper Gutters

Copper gutters are expensive.

Unlike steel gutters, copper does not require a protective layer of paint.Unlike steel gutters, copper does not require a protective layer of paint.
However, when properly installed, their initial cost is offset significantly by their durability and lack of maintenance. Unlike coated steel, they do not require periodic painting. Unlike vinyl or aluminum, copper will last for the life of the average homeowner. To ensure watertight joints, apply solder to join gutter sections.

Lightly sand the ends of the gutters you will be joining. Sand a 1 1/2-inch strip on the bottom side of the upstream gutter. Sand a 1 1/2-inch strip on the top side of the downstream gutter.

Remove sanding dust from both surfaces with a clean cloth. Apply acid flux to both sanded surfaces and press them together. The exposed edge of the seam should now be facing the downstream end of the gutter. Facing the butt-end of the seam downstream allows for a smoother water flow and reduces the risk of leaks.

Heat the soldering iron. The tip should be hot enough to melt solder before you apply it to the copper.

Press the tip of the soldering iron against the surface of the upstream gutter 1 inch above the seam.

Unroll a small amount of solder. Press the end of the solder lightly against the lip of the seam. When the solder melts, it will be wicked between the layers of copper. Move the solder and iron slowly along the seam until the entire seam has been covered.

Things You Will Need

  • 200-grit sandpaper
  • Clean rag
  • Acid flux
  • Soldering iron or torch with soldering tip
  • Solder

Tips

  • Some manufacturers fabricate lock joints on the end of each section of gutter. These will not require an overlap or sanding before solder is applied.
  • Do not use rivets with ferrous materials to join copper gutters. These will rust out over time. If you wish to rivet joints before soldering, use only brass or copper rivets. If you can pick a rivet up with a magnet, don't use it on your gutters.

Warnings

  • Do not use an open-flame torch when soldering gutters on the side of a roof. An open flame could easily cause combustible material behind the fascia to ignite.
  • Wash your hands thoroughly after using solder and flux. Do not eat, smoke or allow any hand-to-mouth contact while soldering.

About the Author

Finn McCuhil is a freelance writer based in Northern Michigan. He worked as a reporter and columnist in South Florida before becoming fascinated with computers. After studying programming at University of South Florida, he spent more than 20 years heading up IT departments at three tier-one automotive suppliers. He now builds wooden boats in the north woods.