weld
Definitions
To join two pieces of metal or plastic by heating the surfaces to the point of melting and pressing them together.
To unite or fuse two or more things into a single, cohesive whole.
Examples
The mechanic had to weld the broken metal frame back together.
It takes a steady hand and a lot of practice to weld two pieces of steel perfectly.
The intense heat of the torch allowed the worker to weld the joints securely.