What Gets Coated and What Should Not Be Coated
Industrial metal finishing processes such as electroplating, electroless nickel plating, hard chrome plating, anodizing, powder coating, and thermal spray coatings improve the performance, durability, and appearance of metal components. These coatings help resist corrosion, reduce wear, increase hardness, improve lubricity, and extend the service life of critical parts. However, not every surface on a component should receive a coating. Many precision-machined features, sealing surfaces, electrical contact points, threaded sections, and weld preparation areas must remain free of deposited metal or protective finishes. This is where metal coating maskants become an essential part of the manufacturing process. Masking protects specific areas of a part before it enters a finishing line, ensuring that only the intended surfaces receive the coating while critical dimensions and functional areas remain unchanged. Common Metal Finishing Processes That Require Masking Many commercial finishing operations rely on masking prior to processing, including: Electroless nickel plating Hard chrome plating Zinc plating Powder coating Anodizing Thermal spray coatings Conversion coatings and chemical passivation Each of these finishing methods deposits a protective layer that can alter dimensions, conductivity, surface finish, or weldability if applied where it is not wanted. Metal Components That Commonly Require Masking Nearly every precision component has areas that must remain untouched during coating. Some common examples include: Pumps Bearing bores Mechanical seal faces Shaft journals Precision mounting surfaces Internal sealing grooves Industrial Piping Threaded pipe ends Weld bevels Flange sealing faces Precision gasket seating surfaces Internal sealing lands Fasteners Threaded portions Drive recesses Bearing surfaces under bolt heads Locking features requiring precise tolerances Hydraulic Cylinders Seal grooves Rod threads Precision piston diameters Weld preparation zones Electric Motors and Electromechanical Equipment Electrical grounding locations Terminal connection points Bearing seats Rotor shaft journals Precision alignment surfaces Valve Bodies Valve seats Stem packing areas Threaded ports Precision-machined sealing faces Structural Weldments Future weld joints Heat-affected preparation areas Grounding pads Assembly locating surfaces Without proper masking, coatings may interfere with assembly, sealing performance, electrical conductivity, or welding operations, leading to expensive rework or rejected parts. Common Types of Metal Coating Masking Materials Selecting the proper masking material depends on the coating process, operating temperature, chemistry, and removal requirements. Masking Tapes High-temperature tapes made from polyester, polyimide, vinyl, or fiberglass materials are commonly applied over flat surfaces or threaded areas. These tapes resist plating chemicals, powder coating temperatures, and aggressive cleaning solutions while providing crisp coating boundaries. Once processing is complete, they are peeled away without damaging the finished surface. Masking Waxes Protective waxes are ideal for irregular shapes, internal cavities, threads, and machined openings. Melted wax is brushed, dipped, or poured onto the areas requiring protection. After the coating process, the wax is removed using heat or appropriate cleaning solutions. Many manufacturers source these materials from a specialized microcrystalline wax manufacturer that formulates products specifically for industrial finishing operations. Masking Liquids A chemical masking liquid offers excellent flexibility for complex geometries where tape cannot easily conform. These liquid coatings are brushed, sprayed, or dipped onto the workpiece before curing into a durable protective film. Following plating or coating, the cured film peels away cleanly, exposing the original metal beneath without affecting dimensional accuracy.
Liquid maskants are especially useful for parts containing intricate passages, grooves, threaded holes, and recessed features. Products for Industrial Masking Applications Among the recognized masking materials available to the surface finishing industry is the family of MICCRO products manufactured by Tolber Chemical. These specialized masking compounds have been developed for demanding plating and coating operations where consistent protection, chemical resistance, and clean removal are essential. One example is MICCRO Shield Masking Liquid, a peelable liquid maskant designed to protect precision-machined surfaces during electroplating, anodizing, and related finishing processes. Once applied and cured, the protective film withstands processing chemicals while preventing unwanted coating buildup on designated areas. After processing, the film can typically be removed quickly, reducing cleanup time and minimizing the potential for damaging finished components. Tolber Chemical also manufactures additional masking compounds formulated to accommodate varying temperatures, chemistries, and production environments, giving finishers multiple options depending on the application requirements. Most industrial masking materials including tapes, waxes, liquid maskants, and specialty compounds are available through U.S. and international distributors that supply chemicals and consumables to the metal finishing and surface treatment industries. These distributors work closely with plating shops, OEM manufacturers, aerospace suppliers, machine shops, and industrial coating facilities to ensure masking products are compatible with specific finishing processes. Successful metal finishing involves much more than simply applying a protective coating. Knowing which surfaces should remain uncoated is equally important for maintaining dimensional tolerances, sealing performance, electrical conductivity, and weld quality. Whether using precision tapes, protective waxes, or advanced liquid maskants, the right masking solution helps manufacturers produce higher-quality finished parts while reducing costly rework. With specialized solutions such as the MICCRO product line, manufacturers can confidently protect critical surfaces throughout the coating process and achieve consistent, repeatable finishing results.
