The bluing process has changed a lot over the years both in the preferred methods and the chemicals used. For many years it was often difficult to have a gun blued and have it match the exact shade it may have been before and nearly impossible to bring a firearm to a gunsmith and have the blue match what may have been done by someone else. The reason for that is that there were numerous home recipes to make bluing salts (the highly caustic compound used to blue firearms) and everything from commercially manufactured ingredients to things like drain cleaner were used. Some of these recipes can still be found on the internet although what results someone may obtain is questionable at best. Today we can obtain commercially manufactured bluing salts which easily repeat the same look every time. This becomes important when only a few parts may need refinishing. The good news is that almost all modern firearms have been blued with black oxide salts to your favorite deer rifle or handgun can be more easily matched.
There are several finishes available from matte blue which is very popular on many hunting rifles as it better holds oil to protect the metal and does not reflect light which can scare game to high gloss which is almost like a mirror finish which is more common on high grade long and handguns with several options in between. Matte finish is a great way to make an old firearm with poor metal condition look great with the least amount of expense.
Here are some examples of what a matte finish can look like as well as how it can economically bring a firearm in poor condition back to a good looking life. This Winchester ’94 was left in a wet sheep skin scabbard and was so bad the owner took steel wool and WD-40 to get it working but cosmetically it was a mess.
Before…
After…
The process is done by heating the bluing solution (which is actually a saturate caustic salt solution) to a temperature much higher than what water boils at (which varies depending on altitude and climate). Because of this there are extreme risks of burns not just from the temperature but of the solution as it’s highly caustic. A single drop can burn with such pain that often people who have tried bluing will no longer do it and I’ve seen good leather boots with holes eaten through them from just one bluing session. Many gunsmiths either have never tried or tried and have burned (some quite badly). So it is very important to be professionally trained not only in the process of bluing but of all the required safety procedures. None of this should be tried at home with out complete and proper professional training.