To solder copper pipe properly, follow these key steps:
Preparation
- Cut the pipe squarely using a pipe cutter, rotating it while tightening gradually until the pipe snaps cleanly
- Remove burrs from inside and outside the cut pipe ends with a reaming tool or deburring tool to ensure smooth edges
- Clean both pipe and fitting surfaces thoroughly with emery cloth, sandpaper (~120 grit), or a wire brush to remove dirt, oxidation, and ensure a shiny copper surface. Clean inside the fitting as well
- Apply flux evenly to both the outside of the pipe end and the inside of the fitting using a brush. Flux helps solder flow into the joint and prevents oxidation during heating
Soldering Process
- Assemble the joint by pushing the fitting onto the pipe fully, then wipe off any excess flux
- Heat the joint evenly with a propane or MAP gas torch, focusing the flame on the fitting rather than the pipe. Move the flame around to distribute heat evenly
- Test the heat by touching the solder to the side of the joint opposite the flame. When the solder melts on contact, the joint is hot enough
- Apply solder to the joint, allowing it to melt and be drawn into the joint by capillary action. Continue applying until a complete silver ring appears around the joint, indicating it is fully filled
- Wipe excess solder and flux off the joint with a clean rag while still warm, smoothing drips and preventing corrosion
Cooling and Testing
- Let the joint cool naturally for 30 to 45 seconds before handling or pressurizing
- After cooling, test the joint for leaks by turning on the water supply
This method ensures a strong, leak-free soldered copper pipe joint suitable for plumbing applications
