1. Explain that the enameled wire that is not directly welded is used. If not, scrape the enameled wire before welding.
2. Since the outer surface of the enameled wire has a layer of oily substance, it mainly plays the role of insulation. So if you do not remove the outer layer of grease, it will not stick to tin. If you want to go, it is best to melt it with fire, so as not to hurt the copper wire.
3. The tin temperature is not high enough, the paint has not melted. It will naturally get tin after melting.
4. The tip of the soldering iron is oxidized. When the soldering iron is used up, tin must be tinned to prevent the soldering iron tip from oxidizing. If it has been oxidized, the oxide layer can be polished with sandpaper.
5. The wire is not easy to tin, soak the wire in rosin first, then you can solder it.