Tinning"Tinning is the process of thinly coating sheets of wrought iron or steel with tin, and the resulting product is known as tinplate. The term is also widely used for the different process of coating a metal with solder before soldering. It is most often used to prevent rust, but is also commonly applied to the ends of stranded wire used as electrical conductors to prevent oxidation (which increases electrical resistance), and to keep them from fraying or unraveling when used in various wire connectors like twist-ons, binding posts, or terminal blocks, where stray strands can cause a short circuit." - (en.wikipedia.org 21.03.2020) Coating