Soldering tip sharpening
Soldering tip should be always sharpened. Copper tip have a disadvantage - tin of the solder dissolving it, causing corrosion.
There is way to slow it down - forge tip edges with hammer.
Soldering tip forms
Regular tip (top) is straight. It is not very convenient in work, much better is some angle of edges (middle). Also, the tip can
be bended to keep edges parallel to soldering iron grip (bottom). Best angle is up to 45°, more is too sharp, making edges
too long. This tip usually is used for unmounting of IC.
Better is burnproof soldering tip, made of copper core with aluminium shielding, since solder tin does not corrode it. This type
of tip does not like overheating - tin is vapourising from it, requiring additional solder tip tinning. Use soldering iron with
power regulator with this tip.