MIG welding (also known as gas metal arc welding) stands for metal inert gas, a type of welding that uses an arc of electricity produced by a fed wire and a layer of inert gas like argon to produce a weld on metals. MIG welding is more complicated than arc welding and less accurate than TIG welding but is very versatile and can be used on a wide variety of substances, including almost all steels, nickel and tin alloys.
Tin for Welding
Most of the tin used today as metal is not actually pure tin but rather steel with an element of tin infused or coated over the top. When we refer to "tin," this is usually what we mean, because pure tin is actually a soft, whitish metal with very few applications outside of certain electrical devices and distillation plants. However, as a part of other metals, tin is very common in the welding process and has a number of applications.
If you have ever bought soldering wire or soldering strips, you have probably seen tin versions for sale, which are alloys in which tin is mixed with lead or other metals and used for a variety of welding purposes. Sometimes pure tin is also sold as a soldering material, although in small quantities and for detailed projects such as making batteries or other delicate operations in which tin's inert qualities are useful. You will probably seen tin most often in the form of tinplate, the tin-coated steel that is resistant against corrosion and used for many different construction purposes.
When welding a steel alloy or a steel that has a protective coating on it, the weld tends to take on the characteristics of the coating rather than the steel beneath, so that coatings must be matched up when welding two metals together. For instance, nickel and chrome-plated steels can be welded together without much trouble, but alloys involving aluminum, tin or zinc will pose more problems, even for MIG welding, and should only be mixed with like alloys.
You should keep in mind that there is a difference between tin and zinc, even though the two are related and used to make the same type of alloys. Both can also be used in the thicker, galvanized sheet metal, which has been dipped in tin or zinc to give it different electrical and resistance properties. Many welders sand off this coating when working with galvanized metals, because melting through it can produce toxic fumes. When starting with a tin-alloy weld, start on low power and weld slowly until you become used to the process.