Of the potentially mysterious terms you will encounter when searching for a high-end putter is “black oxide,” in reference to the finish found on certain putters, as well as some wedges.
Black oxide is essentially a controlled black rust that provides protection against uncontrolled rust, also know as red oxide. Black oxide can also double as a cosmetic enhancement, adding a sleek profile to a club, especially when buffed to a shiny or satin finish on the face and sole of a putter. Another advantage of black oxide is that it helps reduce glare amid sunny playing conditions.
Black oxide is found on industrial parts as well, improving lubricity while protecting against corrosion. Applying black oxide is also known as the process of “gun bluing,” in reference to its popular use on firearms.
In a golf context, why do you find the term associated mainly with high-end putters? Because most of the putters in your local retail outlet are made of stainless steel and/or are plated for a no-maintenance putting experience.
However, some premium putter makers like to offer flatsticks made of precision-milled carbon steel, which is preferred for its soft, supple feedback. T.P. Mills, 350 Milled and Scotty Cameron are among the names associated with pure carbon steel putters.
The rub is that carbon steel is very susceptible to rust, thus requiring a protective finish.
The advantage of black oxide as opposed to plating is that it adds virtually no “build up” on the surface of the steel. According to putter refinisher Black Oxide Service (click here for a photo and personal account of putter refinishing by Black Oxide Service), black oxide adds just five to 10 millionths of an inch to the dimension of a part. It also penetrates to an approximate depth of five to 10 millionths of an inch.
In that sense, it is more of a dye than a coating. Therefore, you get a protective finish while maintaining the pure feel of the parent material, specifically soft carbon steel. When you’re paying $250 or more for a chunk of metal, that can be an important consideration.
Carbon steel putters with black oxide finishes are far from bulletproof. Common foes of black oxide finishes are water and fertilizer, which can compromise the finish and initiate rusting. Therefore, users are encouraged to frequently dry their putters when playing in wet conditions, and to rub them down with a silicone cloth or mineral oil (a.k.a. baby oil) after each use.
An added chore? Perhaps. But well worth it to those who want the feel of carbon steel and the sleek look of black oxide.