Step 6 · Heat the Joint
Unroll about 8-10 inches of lead-free solder from its spool and bend the end at a 90-degree angle. Light your propane torch and adjust the flame to a steady blue cone. Begin heating the joint by directing the tip of the inner blue flame onto the middle of the fitting, not the pipe. Move the flame back and forth across the fitting to heat it evenly. For a 1/2-inch fitting, this should take about 30-60 seconds. You can test the temperature by briefly touching the tip of the solder to the joint seam on the side opposite the flame. If the solder melts instantly and flows, the joint is ready. The flux will often sizzle or smoke slightly just before the correct temperature is reached.