Step 7 · Heat the Joint Assembly
Unroll about 8-10 inches of solder and bend the first inch at a 90-degree angle for easier application. If working near flammable surfaces like wood studs, place a heat shield or flame protector mat behind the joint. Use a spark lighter to ignite your propane torch. Adjust the flame to have a bright blue inner cone about 1-2 inches long. Direct the tip of the inner blue cone onto the middle of the fitting, not the pipe. Heat is transferred from the fitting to the pipe. Move the flame back and forth to heat the fitting evenly on all sides. The flux will begin to bubble and then smoke; this is normal. After about 30-45 seconds, briefly touch the tip of the solder to the joint on the side opposite the flame. If the solder melts instantly and flows toward the heat, the joint is ready. If it doesn't melt, remove the solder and continue heating for a few more seconds.