Most outdoorsmen at one time or another decide to purchase a heirloom quality knife. Whether for cleaning fresh game, preparing a meal in the kitchen or for outdoor survival, a knife is a valuable tool to own. Most handmade “heirloom” quality knives are made of a high carbon steel; as high carbon steel tends to hold a sharper edge longer and requires a less specialized sharpener to maintain said edge.
While high carbon steel has many sought after qualities, it has one major setback, rust. The high carbon content can begin to rust if exposed to moisture, salt or certain harsh chemicals.
Over the years, there have been many technological advances in metal treatments and rust. However, due to the heat required in many of the expensive spray on coatings, they often change the properties of the steel. One of the tried and true way is a method of old, the old timers used desired rust to fight undesired rust. This is also known as adding a patina to the steel. A Patina is a coating on the surface of the steel that often looks like tarnish, but prevents undesired “red rust” from damaging the surface of the steel.
While I am no chemist, but I believe the difference in Rust and Patina lies in the levels of iron and oxygen present on the surface of the steel.
In order get a dark patina on a knife blade, One will need the following items:
- Container large enough for the blade ( long cup or vase worked for me).
- Distilled White Vinegar.
- Microwaveable container.
- Towel (Use an OLD towel)
To get started, the vinegar will need to be placed in the microwaveable container and heated for approximately 1 minute.
Next, the hot vinegar will be placed in the container of choice for the knife.
Now we can start the fun part, carefully place the knife in the container, taking care not to get the vinegar on the knife scales ( NOTE: this is especially important if the knife has wood scales).
The longer the soak, the darker the finish will be. The knife shown in the photos was soaked for several minutes, and wiped to check the color.(Use an old towel!!)
And the finished product should look like this!
In conclusion, the vinegar gives the dark patina that I prefer. However, If one wants the blueish finish, sticking the knife in a potato seems to give a nice blue/black tint.
Good Luck and practice safe knife handling!