Why do you need rosin for soldering iron? How to use rosin for soldering iron
Rosin is used as a soldering flux in welding, serving as a soldering aid. In theory, the melting point of solder is lower than that of solder, and its specific gravity, viscosity, and surface tension are all lower than that of solder. Therefore, during welding, the solder melts first and quickly infiltrates and covers the surface of the solder, serving to isolate air and prevent oxidation of the metal surface. It can also react with the surface oxide film of the solder and the metal being welded at high temperatures to melt and restore the pure metal surface. Appropriate soldering helps to create satisfactory solder joint shapes and maintain the surface gloss of the solder joints.
Rosin is the most commonly used soldering flux, which is neutral and does not corrode circuit components and soldering iron tips. If it is a newly printed circuit board, a layer of loose perfume should be coated on the surface of the copper foil before welding. If it is a pre made circuit board, it can be directly soldered. In fact, the use of rosin depends on personal habits. Some people soak the soldering iron tip in rosin after soldering each component; I always dip some rosin on the soldering iron tip when it is oxidized and inconvenient to use. The use of rosin is also very simple. Open the rosin box and soak the electrified soldering iron tip on it. If solid solder is used during welding, adding some rosin is necessary; If rosin tin welding wire (with flux wrapped inside the wire core) is used, rosin can be omitted.
Due to the formation of an oxide film on metal surfaces in contact with air, the higher the temperature, the more severe the oxidation. This oxide film prevents liquid solder from wetting the metal, just like oil on glass prevents water from wetting it. Flux is a specialized material used to remove oxide films, also known as soldering flux.
Flux has three main functions:
1. Remove the oxide film. The essence is that the substances in the flux undergo a reduction reaction, thereby removing the oxide film, and the reaction products become suspended slag floating on the surface of the solder.
2. Reducing surface tension and increasing solder fluidity can help solder wet the workpiece.
3. Prevent oxidation. After melting, it floats on the surface of the solder, forming an isolation layer, thus preventing oxidation of the welding surface.
