What is the Difference Between Rust Blue, Mark Lee Express Blue and Belgian Blue?

Bluing has to do with gun refinishing. Rust blue, Mark Lee express blue and Belgian blue all are refinishing solutions for gun barrels. This particular name refers to a gunsmith's procedure to color the barrel akin to refinishing wood. Rust blue, Mark Lee express blue and Belgian blue produce three different shades of blue.

  1. Bluing

    • Bluing is a procedure known to gun enthusiasts as a refinishing technique for the metal sections of a gun. Rust bluing was used for centuries prior to tank bluing being invented. Bluing preparation begins with stripping of an old finish, then polishing the surface with fine grit metal sandpaper. Preparation includes applying the bluing finish a number of times and submersing the finish in boiling water. The application/boiling procedure is repeated as many as 10 times until the desired finish is obtained.

    Slow Rust Bluing

    • Pistols are also refinished using a bluing procedure.

      Slow rust bluing is the oldest rust blue process, and is considered by many as the most appealing blue finish. Hot tank bluing is more dangerous, using a chemical mixture that more permanently embeds a bluing finish. The home gunsmith and hobbyist can easily do slow rust bluing compared to the hot-bluing processes. The gun barrel being blued is boiled in a humidity box, which is simply the prepared box for the boiling water. The barrel being blued is plugged by wooden pieces inserted in the barrel, since some gun enthusiasts don't want bluing within the barrel.

    Mark Lee Express Blue

    • Mark Lee Express Blue is a specific brand of bluing formulation that is well regarded because it applies quickly and easily. It is a cold bluing finish, which is defined as a bluing finish that is applied without harsh chemicals. The gun metal is sanded to the finish preferred with a 320 fine grit metal sandpaper, degreased, and a layer of Mark Lee Express Blue is wiped on the metal. When a thin film of orange-tinged rust appears, the applied metal is boiled, dried and carded off with steel wool. "Card off" is the gunsmith term for sanding.

    Belgian Blue

    • Art's Gun & Sport Shop owns the original Herter's Belgian Blue formula, and Belgian Blue is often referred to as Art's Belgian Blue. Art's Belgian Blue is an accelerated rust blue that is durable. It's a balanced combination of bluing salts and acids that produce a bluish patina on all gun steels except stainless steel, the shade of which is determined by the number of boiling/polishing sequences. Belgian Blue also refers to a breed of cattle from Belgium.