Temperature:
The weller tips came out with say number '8' stamped on the bottom of it (meaning it heated up to 800°F) for there magnetically controlled soldering irons I think the tip series were 7, 8, 9 (or was 6,7,8)
By not sure if I missed the part were "lead free" solder needs a higher temperature soldering iron.
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How to replace surface mount parts.
The best way I was taught to replace surface mount parts.
(1) Take off the old part,
(2) Simultaneously heating and rubbing tined copper braid known as solder braid or solder wick and a standard hot iron to soak up any old solder,
(3) Clean up tracks with isopropyl alcohol and tooth brush,
(4) Then apply a trace of solder paste over the copper tracks from a small syringe of paste,
(5) Then put the surface mount IC on top and blow hot air over it until the paste melts and solders the part in place.