Welding is a fabrication process that joins together two materials, more often than not two metals, by causing coalescence. Coalescence is achieved by melting the two workpieces at the point where they are to be bonded to form a common ‘weld pool’ of molten material (a filler material is sometimes also added). When the pools cools down to form a solid, the two pieces are joined together by a strong joint. The same can also achieved by using a combination of pressure and heat or sometimes just pressure to form the weld. Many energy sources can be used for welding including an electric arc, a gas flame, a laser, an electron beam, friction and ultrasound. There are lots of different welding & safety equipment used to help with these processes including: mig welders, mig torches, arc welders, spot welders, plasma cutters, positioners, visors, goggles.