The solution to the soldering iron not hanging tin
(1) Disconnect the power source, remove the soldering head while the soldering iron cools (note: don't fold the heating rod when disassembling), and grind off the black non-hanging tin layer using the prepared 1000 mesh sandpaper. Of course, the fine sand surface of the domestic whetstone can also be polished if sandpaper is difficult to procure.
(2) Attach the electric soldering iron to the copper-colored welding head, and connect the power source.
(3) Touch the soldering iron tip with a rosin-cored solder wire when the temperature of the tip is steadily rising (notice that at this point, do not dip the soldering tip in rosin and an absorbent sponge). The solder wire gradually starts to melt as it transitions from the initial non-melting state to the gradually rising welding head temperature. The solder can now be hung when the solder wire has been touched to the full copper-colored surface of the soldering head.
(4) Apply the rosin after dipping the soldering head in it.
