Step 7 · Heat the Joint

This is the step most people slow down on. Take it one move at a time — there’s no rush, and you can rewind the clip as many times as you need.

Ignite your propane torch and adjust the flame to have a bright blue inner cone about 1-2 inches long. The tip of this inner cone is the hottest part of the flame. Apply the heat to the fitting, not directly on the pipe. The goal is to heat the fitting, which will then transfer heat to the pipe inside it. This is crucial for drawing the solder into the joint via capillary action. Keep the flame moving around the entire circumference of the fitting to heat it evenly. The flux will start to smoke and then bubble; this indicates it is working and the joint is approaching the correct temperature. You can test the temperature by briefly touching the tip of the solder to the joint seam, opposite the side you are heating. If it melts instantly, the joint is ready.