How to Use Rosin in soldering？

How to Use Rosin in soldering？

Rosin is the most common flux. It is neutral and won't corrode circuit components or the soldering iron tip.It is better to apply a layer of rosin on the surface of the newly printed circuit board before welding.Actually, whether to use of rosin or not depends on personal habits. Some people dip the soldering iron tip into the rosin after soldering each component. and some people usually dip the soldering iron tip into the rosin only when it gets oxidized and becomes inconvenient to use. The use of rosin is quite simple. Just open the rosin box and dip the heated soldering iron tip into it.

The Role of Rosin in Welding

The melting temperature of the flux is much lower than that of the solder, and its specific gravity, viscosity, and surface tension are all smaller than those of the solder. Therefore, during welding, the flux melts first and quickly flows and covers the surface of the solder, playing a role in isolating the air to prevent the oxidation of the metal surface. It can also react with the oxide film on the surface of the solder under the high temperature of welding, dissolving it and making the metal surface pure and newly again. Appropriate flux helps us to get satisfactory solder joint shapes and maintain the surface luster. Since the metal surface will form an oxide film after contacting with the air, and the higher the temperature is, the more severe the oxidation will be. Flux is a special material used to remove the oxide film and is also called soldering flux. Soldering flux has three main functions:

1. Remove the oxide film. In essence, the soldering flux undergo a reduction reaction to remove the oxide film, and making the Oxide film turn into suspended slag floating on the surface of the solder.

2. Prevent oxidation. After the flux melts, it floats on the surface of the solder, forming an isolation layer, which can preventing the oxidation of the welding surface.

3. Reduce the surface tension and increase the fluidity of the solder, helping the solder to wet the welded parts.