What does "soldering" mean in pipefitting?

Soldering in pipefitting refers to the process of joining two metal parts by melting a filler metal. This method is commonly used for creating secure, leak-proof connections in copper and other metal pipes. During soldering, the filler metal, typically made of a lead-tin alloy or silver, is heated to its melting point and applied to the joint between the two metal components, where it cools and solidifies, forming a strong bond. This technique is especially useful for plumbing applications where durability and resistance to corrosion are crucial.

In contrast, other methods mentioned in the choices may refer to different processes or materials not applicable to the specific definition of soldering. For example, welding for heavy pipes involves high temperatures and specialized materials, while connecting plastic pipes would fall under different joining methods, such as solvent welding or mechanical fittings. The mention of drainage pipes suggests a type of joint but does not encompass the specific characteristics of soldering. Thus, understanding that soldering is distinctly about metal joining with a filler metal is key to grasping its application in pipefitting.