Step 7 · Apply Solder
Once the joint is at the correct temperature, remove the flame from the fitting. Immediately touch the tip of the lead-free solder to the seam where the pipe enters the fitting. Do not apply the flame directly to the solder. The heat stored in the copper fitting and pipe will melt the solder. Capillary action will then pull the molten solder into the narrow gap between the pipe and fitting, filling the joint completely. Move the solder around the entire circumference of the joint until you see a continuous silver ring form. For a 1/2-inch fitting, you will only need about 1/2 inch of solder. Once the joint is filled, remove the solder wire and let the joint begin to cool.