Steel rusts. There is no such thing as stainless or rust proof steel. The steel that we use is 154cm and it is a high carbon tool steel. It's formula just qualifies it as a stainless class steel. Our steel, 154cm, will rust given the right or should I say, wrong circumstances.
The stonewashed finished knives are raw steel with no coating. That means there is no protective barrier between the steel and the environment.
We do offer black coated blades.
Why do some of the stonewashed blades show surface rust? Because they have been exposed to an environment conducive to rust. It's really that simple. We wipe all of our blades down with Sentry Tuf Cloth prior to assembly to give them that measure of protection. However, after exposure to certain environmental conditions or after someone has wiped or cleaned off the Tuf Cloth solution, the steel is then exposed.
The question then comes up, “Joe has the same exact knife with the next serial number, we live next door and even carpool to work. Why does mine rust and his does not? Does mine have bad steel or a bad heat treat?”
Every individual has a slightly different body chemistry. It can be the result of dietary or hereditary causes. Sometimes both. This means that when measured very precisely everyone has their own personal PH level. As a result, some peoples perspiration is slightly basic, some neutral and some acidic. I have worked with people who touch a piece of bright steel and literally within 30 seconds a bright orange fingerprint starts to appear on the surface. And I mean I have seen this in a number of individuals over the years, perhaps dozens.
So, there are people who have varying degrees of acidity or alkalinity in their perspiration. It's not good. it's not bad. It just is.
So, you take a knife and it gets little particles of dust, dirt, or lint on it. These particles are generally hydroscopic, meaning they can attract and hold moisture. Couple that with the possibility that a person may have a slightly acid PH and I guarantee that you will see some surface rust over time.
A knife that is carried in the pocket does and will rust if the individual carrying it has a slightly acid PH, even if it is never taken out of the pocket. Remember perspiration wicks out through the layers of clothing and a pocket is full of lint.
Knives, just like guns need to be cleaned and lubricated to keep them in good working order and to prevent rust.
There is nothing wrong with the knives. They are stain resistant, not rust proof. The steel we use is a battle proven combat ready steel that does exactly what our users want and need. As you may have noted over the years I do not chase after the new “super steel” every year when a new one comes out. I'm not going to trade out performance for a steel used by another company just because it doesn't rust.
The bottom line is, just like I do with very expensive guns and my 600 year old Japanese swords. I keep them clean and I oil them to prevent rust, (Not the swords).
I hope this gives some explanation to the questions about surface rust on some peoples stonewashed blades.