What occurs when soldering a copper connection and solder is drawn into the joint?

When soldering a copper connection, the phenomenon that allows solder to be drawn into the joint is known as capillary action. Capillary action occurs when a liquid, such as molten solder, moves through narrow spaces without the assistance of external forces. In the context of soldering, when the heated solder comes into contact with the joint, it is able to flow into the tiny spaces between the copper pieces due to the cohesive forces between the solder and the adhesive forces between the solder and the surfaces of the copper.

This characteristic of soldering is critical as it ensures a strong, reliable bond between the two copper surfaces. Proper application of heat allows the solder to melt and fill voids, thus creating a tight seal that enhances the integrity of the connection. Understanding capillary action is essential when performing soldered joints, as it directly relates to the quality and effectiveness of the solder connection in refrigeration systems.