What is the purpose of flux?

Flux plays a critical role in the process of soldering and metal joining. Its primary purpose is to remove surface oxides from the metals being joined. Oxides can form on metal surfaces when exposed to air, which can significantly hinder the bonding process during soldering. By cleaning these oxides, flux ensures that the solder has a clean, unblemished surface to adhere to, which promotes a strong and reliable joint.

While some substances may help with other tasks, such as aiding in the melting of base metals or cleaning tools, these functionalities do not encapsulate the primary role of flux in soldering specifically. Flux is essential for achieving good electrical contact and mechanical strength in soldered joints, as it enhances the flow of solder by allowing it to penetrate the joint more effectively.