Brass pipes cannot be joined by which method?

Brass pipes cannot be joined by soldering due to the melting point of the solder and the properties of brass. Soldering involves melting a filler metal, which is typically lead-based or tin-based, at a lower temperature (around 180-250°C or 350-480°F) compared to the melting point of brass itself. This connection technique can result in the weakening of the brass, making it unsuitable for high-pressure applications or environments where the connection must withstand significant stress.

Brass, being an alloy of copper and zinc, has good thermal conductivity, but soldered joints can be compromised over time, especially when exposed to high temperatures or pressures. Other joining methods, such as welding and bolting, can provide much stronger and more reliable connections for high-pressure systems, while threading is a common and effective way of joining pipes for plumbing and mechanical applications. These methods do not rely on a filler metal that could potentially weaken the joint, making them more appropriate for use with brass pipes.