Final answer:
Hard copper tubing can be joined by soldering, brazing, and using compression fittings, each providing a different level of strength and application suitability.
Step-by-step explanation:
Hard copper tubing can indeed be joined using a variety of methods, such as soldering, brazing, and compression fittings. Soldering involves the use of a filler metal, solder, which is melted to form a joint between the pieces of copper. Brazing is similar to soldering but uses a higher-temperature filler metal that allows for stronger joints. Compression fittings create a seal without the need for melting any metals, through a mechanism that compresses a fitting against the tubing with a threaded nut, creating a watertight seal.