Reasons for using rosin when soldering with electric soldering iron
Rosin, a soldering flux.
1. The soldering iron head is not stained with tin. After being stained with rosin, the tin will easily melt and stick to the soldering iron.
2. The tin wire is made very thin because it is easy to melt and coated with rosin, so that the thin tin wire can be melted into a round and full drop shape instead of running around.
3. The solder is dropped directly on the solder joint. If the solder joint is clean or oxidized, it is easy to have weak contact and fall off at a touch. Adding rosin can help remove the negative effects of oxidation and make the solder stronger.
4. Without solder, the solder will easily stick when the soldering iron is removed from the solder joint, causing the solder joint to be unsightly.
5. If it is dropped directly, it means that the process requirements during welding are not high, or too much is dropped, causing unnecessary waste.
Rosin is a strong reducing agent that can reduce aluminum oxide and tin-lead oxide (both lead and tin have two oxides corresponding to two valence states) to generate corresponding metals and welding slag. Normally, it should not be stained. solder.
The tip of the soldering iron does not occupy tin, and the melting point of 60 tin-40 lead solder is relatively high. Both metal oxides and organic oxides generated by oxidation of rosin have poor thermal conductivity. The tin wire cannot continue to obtain heat as soon as it melts, so it cannot flow into a ball. Down.
If you don't know what you want to solder, it's a good idea to deliberately oxidize the back of the soldering iron tip so that the front side continues to eat tin and eventually drip off. The tin wire is very thin. The thinnest tin wire is of very poor quality and has extremely poor fluidity. It cannot drip into a ball at all. It is recommended to replace it. Slag tin and waste incense cannot weld anything at all.
Finally, after the solder ball drops onto the metal surface, there is no time for solid-liquid fusion, and the contact surface is loose and unstable, making it extremely easy to solder.
