Soldering is a technique that has many applications both industry related or recreational. Essentially, it is the process of melting a tin and copper mixture, called solder, so that it binds with other metals, but the tools can also be used to melt or cut other materials. The unique techniques for these applications involve a high level of craftsmanship, but can be learned quickly and perfected with practice. The two main tools used for this will be either a soldering iron or a soldering gun. Although these tools are similar, their applications will vary based on their inherent nature.
The soldering iron is perfect for binding fragile electronics and delicate jewelry. The gun runs from a range of 15-30 watts, reaching up to 350 F. This allows it to easily melt the solder or other light metals in a matter of minutes. The tool is capable of completing procedures that require precision as apposed to intense melting power. This is why the iron is generally used for binding smaller materials: In electronics it is used to create currents by properly bonding metal conductors and in jewelry it can be used to successfully bind precious metals without damaging them.
The soldering gun is intended for applications that may require more heat than the iron. The robust output of the gun ranges from 100-240 watts, allowing it to reach degrees up to 2400 F, so it can be used in jobs that require melting heavier solder or a cutting through stronger metal. For example: Plumbing uses the gun to seal copper piping, stained glass artisans use it to fill the space between the glass shapes, and metal worker will even use it to cut precise shapes out of sheet metal.
Although these tools both essentially serve the same function, heating and melting metals, based on their power they must be used for completely different purposes. This just shows how the application of soldering is so broad; it is not limited to one application, and even requires different strength tools. Therefore, when trying to understand the difference between a soldering iron or gun, it is more important to understand what needs to be accomplished with the tool. The soldering iron does not have the capacity to melt strong metals or solder and the soldering gun will be completely impractical for precise electronic soldering or crafting jewelry.