Welding is a process of fabrication that involves the use of heat and pressure to fuse two or more parts. This method of joining new or broken pieces is usually used on thermoplastics and metals. However, the same procedure can also be done in parts of wooden materials. 'Weldment' is the term used to refer to the completed process of the welded joint, and the parts that have been joined are known as the parent material. The material added for forming the joint is called consumable or filler.

Unlike soldering and brazing, welding melts the base material, as it is a high heat process. This process makes a material stronger than the parent material. Shielding gas can also protect filler metals and melted metals from becoming oxidised or contaminated. In joining plastics, the same procedure is used, but the joining methods can be separated into internal or external heating methods. For joining wood, the process involves the generation of heat from friction. In this regard, a lot of pressure subjects the materials to be joined before a linear friction movement heats for bonding the pieces together. This process is fast and can join wood without nails or adhesives within seconds.