What are files coated with?
|Usually, files do not have protective coatings or finishes added when they are made.|
|This is because files are abrasive tools, i.e. their main function is to rub against a surface and wear it down.|
|Most coatings are unsuitable for this, as they would wear off very quickly, therefore making it a waste of money and resources to put them on!|
File coating: the only option…
|One type of protective coating that can be used is black oxide coating.|
|This is the same kind of coating that is used for guns and knives, as well as some other tools such as spanners and drill bits.|
|The process of coating steel in black oxide involves soaking it in a bath of caustic chemicals that react with the surface of the metal.|
|This reaction causes the metal to oxidise in a specific way, coating the entire tool in a thin layer of magnetite.|
|Magnetite (Fe2O3) is a specific type of iron oxide that occurs in nature in rocky mineral deposits. Using this coating is like wrapping your file in a thin layer of rock!|
|The coating provides limited protection against corrosion, but does help to keep the tool sharp; a DIYer would have to wear through the black oxide coating before they could start to blunt their file.|
|Even though it’s quite cheap to coat tools in black oxide, you are still more likely to find files that are uncoated.
This is because the elements used in the tool steel that the files are made from increase the file’s hardness as well, and also provide some resistance to corrosion.
|Still, it can be argued that a black oxide coating can be beneficial, especially if you’re a fan of the belt and braces approach!|