Gunsmith’s Guide to Metal Prep for Baking & Bluing
By Eric Kiesler

Prior to bluing or the application of a bake-on coating, a steel surface must be properly prepared. In either case, at a minimum the work piece must be thoroughly and completely degreased. There are many acceptable ways to degrease steel parts, so long as no residue remains the method used is not critical. We typically recommend TCE (#083-060-024) for degreasing prior to the application of Brownells Baking Lacquer (#083-046-801) or Oxpho Blue (#082-024-004). The TCE in the spray can is preferable as it allows you vigorously spray the surface, start at the top of the part and hose it down to the bottom chasing the grease off.

Prior to hot caustic Bluing (#082-005-007) the parts are immersed in a heated detergent bath using Dicro-Clean (#082-005-008) because (like TCE) we know it will have no adverse after effects or residue that could cause problems later on. Once the degreasing is complete, the part could be blued or coated, however, with bake on coatings, adhesion is greatly enhanced if the surface of the parts are roughed up. This can be accomplished by sanding them with a fine abrasive cloths, sand paper, Emory Cloth (#657-110-120) or by abrasive blasting. Abrasive blasting is preferable because it will typically reach areas that sand paper might not.

For the Gun Kote (#083-051-001) brand of bake-on finish, aluminum oxide (#084-206-060) must be used as the abrasive blasting media in your abrasive blaster. For our other bake on coatings (and even Aluma-Hyde) sand or glass beads may be used in the blaster. If you do abrasive blast the part (highly recommended), it should be degreased afterwards because the blasting media may have contaminants in it. You don’t want to coat a highly polished part since shiny metal resists the coating, but a highly polished part could certainly be blued.

CLICK HERE to Read Entire Article | CLICK HERE for GunTech™ Archive of Articles

Watch Brownell’s Video on Rust Removal

Brownell’s technician, Steve Ostrem, notes that many things can promote rust — some you might not expect. In addition to moisture in the air, rust can be caused by the salts and oils from your hands, sweat, blood, or even insect repellent. Ostrem also observes that temperature changes can produce condensation which may lead to rust inside the gun that you don’t even notice: “In the real world we know that if you take the gun outside, sooner or later, it’s going to rust. When you come inside, wipe the gun down the first opportunity you get. If you bring a cold gun into a warm, humid house, you’re going to have an instant coating of moisture… make sure you get the gun dried off and you’ll avoid a lot of problems.”

Rust Prevention
We’ve conducted a comprehensive test of corrosion-fighters. Among the best products to prevent rust are Boeshield T-9, Corrosion-X, and Eezox. Break-Free also works well, but it leaves a somewhat greasy residue, and it did not perform as well during long-term salt exposure as did the other three products.

For long-term storage, nothing beats a coating of Cosmoline, Rig or similar grease. This provides a barrier layer that blocks the oxidation process, which is how rust forms. These greases performed extremely well in a comparison test of Rust Preventative Products performed by Brownell’s. CLICK HERE for Comparison Test.