Soldering flux is a substance that aids in the soldering process by removing oxidation and promoting wetting for a better connection between two metals. It is a paste, liquid or even powder form or mix used in the soldering process to help make the solder joint stronger and denser. This also improves the electrical and thermal connections between the surfaces being soldered, as well as making it easier for the solder to flow and form a stronger bond. Soldering flux also prevents oxidation and corrosion of the joint, increasing the lifespan of the connection.