What is the primary method that welding employs to fasten materials?

Welding primarily involves melting the metal to create a strong, permanent bond between two materials. During the welding process, heat is applied to bring the material to its melting point, allowing the edges to fuse together as they cool and solidify. This method is highly effective because, when done properly, it creates a joint that is often as strong or even stronger than the original materials being welded.

The other methods mentioned are used for fastening materials in different contexts, but they do not involve the same process as welding. Applying adhesives relies on a chemical bond to hold materials together without melting them. Using screws involves mechanically fastening pieces with threaded fasteners, which creates a joint but does not change the state of the materials through heat. Binding with rubber is another form of fastening that utilizes elasticity, which can be effective in certain applications but lacks the structural integrity provided by welding. Thus, melting the metal is the defining characteristic of welding that distinguishes it from other fastening techniques.