Coated vs Non-coated CPM REX 45

CPM REX 45 is a high-carbon tool steel prone to oxidation and patina formation, especially when exposed to moisture or acids. Its low chromium content means it lacks the corrosion resistance of stainless steel, making patina more likely. A patina can protect against deeper corrosion, and some users encourage it for both aesthetics and protection. Regular oiling and drying can help manage rust while allowing a natural patina to form.

An uncoated CPM REX 45 blade will require regular maintenance and proper care to ensure longevity and to protect against deep corrosion and rust. Some users “force patina” on a new CPM REX 45 blade to create the worn in look right away. The patina formed with proper and careful TLC is a unique benefit of our steel choice, but it does require more attention than your average EDC blade.

A coated finish on REX 45 will provide a sleek, stealth look to the blade, while offering protection against rust and corrosion. However, a coated blade will not form a unique patina over time.

Bottom line: Each choice brings distinct benefits, whether for ease of use or the character of a natural patina.

Check out some patina examples from @attila and @knifemovieguy from the Spyderco forums!

For more information see: Weighing the Pros and Cons of Uncoated High-Carbon Blades