Welding is a process used to join two or more materials together, usually metals or thermoplastics. The most common welding processes are ARC welding, FUSING, brazing, soldering, wave soldering, and reflow soldering. ARC welding uses an electric current to create an ARC between the metal pieces, which melts the metal and allows it to be joined together. FUSING is a process that uses heat to melt the metal pieces and join them together. Brazing is a process that uses a filler material to join two pieces of metal together. Soldering is a process that uses a low-temperature solder to join two pieces of metal together. Wave soldering is a process that uses a wave of molten solder to join two pieces of metal together. Reflow soldering is a process that uses a heated solder paste to join two pieces of metal together.