Let’s say there are some Spyderco Knives in your collection that have K390 steel blades, such as an Enuff 2. This is a great steel and one that is very tough and hard. It will hold an edge for a long time. 

There is just one real tradeoff. This alloy will rust. 

The upside of this is that steels that will rust will often patina beautifully. Here’s what you need to know about this phenomenon, along with how you can force one if you so want. 

What Is a Patina?

A patina is a natural occurring discoloration that forms on non-stainless steel alloys under mild oxidative stress. Like rust or “red” rust, a patina is a form of oxidation, although it occurs under lower oxygen concentrations. Sometimes it is called “black” rust because the color is usually blackish, though it can also be brownish, or bluish.

A patina is as unique as a fingerprint, and no two are the same, so there is aesthetic value associated with them, but the real reason that a patina is desirable on a knife blade is because it will help insulate the steel against further corrosive stresses.

While it will not entirely present the presence or proliferation of rust, a well-established patina on a carbon steel blade will help shield it against mildly corrosive influences. 

Moreover, you can get a patina to naturally form on high-carbon, non-stainless alloys like D2, 1095, and K390 over time, with no effort on your part, but you can also simulate conditions that will force a patina to develop quickly. Here’s what you need to know on that front.

How to Do It

There are many ways to get a patina to develop on high-carbon steel alloys, but one of the easiest ways requires only a few minutes and a tablespoon or so of mayonnaise. 

Open your knife and dip the blade in the mayonnaise, ensuring that it has evenly covered the blade. Remove the knife from the mayonnaise and place it on a piece of paper towel. Set a timer for 5 minutes. 

After 5 minutes have elapsed, run the knife blade under hot water to ensure that all the mayonnaise has been removed from the blade. You should notice blackish or brownish discoloration on the blade. This is your new patina. 

If it didn’t work, repeat the process. 

Once you’ve rinsed the blade, double check to ensure that all mayonnaise has been removed, then thoroughly dry the blade before treating with oil. You want to make sure that no mayonnaise or moisture remains on the blade in order to prevent rust. 

And that’s basically all there is to forcing a patina on a carbon steel blade. 

Shop Spyderco Knives Online at River’s Edge Cutlery 

Don’t have any Spyderco Knives with K390 steel blades yet? You can change that today and even try your hand at forcing a patina. Visit River’s Edge Cutlery and see what’s in stock; they carry plenty of Spyderco Knives as well as other top brands, some of them in non-stainless alloys that will readily develop a beautiful patina.

For more information about Demko Knives and Benchmade Knives Please visit: River's Edge Cutlery.