What is the most common method of joining copper tubing?

Soldering is the most common method of joining copper tubing because it creates a strong, durable bond between the tubing ends without the need for high temperatures, as in welding. It involves melting a filler metal—usually a tin-lead or lead-free alloy—around the joint which solidifies and forms a tight seal. This method is ideal for plumbing and HVAC applications, where reliable joints are essential to prevent leaks.

Additionally, soldering does not alter the structure of the copper tubing as much as welding does, which could weaken the material or create distortions. Unlike compression fittings, which may be easier to install but can be less secure in the long term, soldered joints provide a permanent solution that's well-suited for systems carrying liquids or gases. Overall, the reliability and strength of soldered joints make them the preferred choice for professionals working with copper tubing.