Metal Prep for Surface Refinishing (Bluing and Resin Finishes)
In Brownells’ GunTech™ Archive of instructional articles and videos, Eric Kiesler has written an informative Guide to Metal Prep for bluing or bake-on resin coatings. Eric’s “how-to” advice will be useful for prepping something as small as a scope ring or as large as a complete barrelled action. Here is a selection from Eric’s article:
Gunsmith’s Guide to Metal Prep for Baking & Bluing
By Eric KieslerPrior 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.
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