Why Coat Metal Components?
Bare metal can be affected by moisture, chemicals, abrasion, impact and repeated handling. Moving components may also suffer from friction, while conductive surfaces may require insulation before they can be used safely within electrical equipment.
A coating provides an additional layer between the metal and its surroundings. This layer may be relatively thin, as with some PTFE and bonded lubricant systems, or considerably thicker where impact protection, insulation or a softer surface is required.
The purpose of the coating should be considered at the start of the project. A component intended for outdoor use will have different requirements from a fastener used within a petrochemical plant or a bus bar installed inside an electrical system.
Key Performance Benefits of Plastic Coatings
Protection Against Corrosion
Corrosion can weaken metal components, affect their appearance and eventually lead to failure. Moisture, salt, chemicals and atmospheric contaminants can all contribute to the process.
A suitable coating separates the metal from these conditions. Its effectiveness depends on the coating material, substrate condition and preparation before application.
Electrophoretic painting, or e-coating, is one option where consistent corrosion protection is required. Because the component is immersed in a coating bath, detailed and recessed areas can also be covered.
Automotive brackets and battery trays are typical examples. These parts often contain folds, corners and fixing points while being exposed to moisture and road contaminants. E-coating can provide a consistent protective layer and may also act as a primer beneath another finish.
Improved Wear & Impact Resistance
Metal components used in industrial environments may be knocked, scraped or repeatedly brought into contact with other surfaces. This can damage the component or the products around it.
Thermoplastic coatings can provide a thicker and more forgiving surface than many paint systems. They can absorb minor impacts, resist abrasion and cover hard metal edges.
Industrial wirework is one example. Guards, baskets and handling frames may be moved frequently or used to carry finished products.
A thermoplastic dip coating can protect the wirework while reducing the risk of marking or scratching the items being handled.
The required thickness depends on the component design and the type of wear involved. A coating suitable for occasional handling may not withstand continuous abrasion.
Reduced Friction
Friction affects how components move, assemble and separate. Too much friction can cause wear, make assembly inconsistent or create difficulties during maintenance.
PTFE and bonded lubricant coatings provide a dry, low-friction surface. They can reduce direct metal-to-metal contact without relying entirely on oils or greases.
Fasteners used in the petrochemical industry are one example. Nuts, bolts and threaded components may operate in demanding environments but still need to be removed for inspection or maintenance. PTFE-based coatings or bonded lubricants can reduce friction while contributing to corrosion protection.
Plastic Coatings applies specialist systems such as Xylan to petrochemical fasteners. Specifications may include degreasing, phosphate pretreatment and one or more coating layers.
The system must suit the required tightening characteristics, temperature range and chemical environment.
Electrical Insulation
Metal conducts electricity, which may be undesirable or unsafe in some applications. A suitable plastic coating can create an insulating barrier between the metal and nearby equipment or users.
Electrical performance depends on the coating material, film thickness, component geometry and completeness of coverage.
Bus bars are a clear example. These metal conductors distribute electrical power within vehicles, aircraft and industrial equipment. The main surfaces require insulation, while connection points may need to remain uncoated.
Thermoplastics such as PPA, Nylon 11 and Halar ECTFE or thermosetting materials like Resicoat can be used where insulation and environmental resistance are required. The operating voltage, component design and service environment determine the most suitable material and thickness.
Masking and testing may also be needed where critical contact points or defined insulation performance are specified.
Chemical Resistance
Metal components in industrial environments may be exposed to fuels, oils, cleaning products or process chemicals. These substances can attack the metal or cause an unsuitable coating to soften or lose adhesion.
Chemical resistance must be assessed against the specific substance involved. Concentration, temperature and exposure time can all affect performance.
Valve components used in the energy and petrochemical sectors provide one example. They may need to move reliably while operating in aggressive conditions. A fluoropolymer or thermoplastic coating can protect selected surfaces while providing friction or release properties where required.
The system should not be selected using a general claim of chemical resistance. The chemical, operating conditions and required service life must all be considered.
Improved Safety & Handling
Bare metal can be cold, hard or uncomfortable to grip. Edges and contact points may also become difficult to handle during repeated use.
A thicker plastic coating can create a warmer, more tactile surface. It may improve grip, soften contact areas and prevent direct contact with the metal.
Thermoplastic coating is well suited to handles, handwheels and control levers. The metal provides the required strength, while coatings like PVC plastisol, PPA and Nylon form a flexible outer layer that is more comfortable to hold.
The coating can also provide impact, abrasion, thermal and electrical insulation properties. Its final thickness and texture should reflect how frequently and intensively the component is used.
Longer Service Life
A coating can extend component life by reducing the effects of corrosion, abrasion and impact. This may allow the component to remain in service for longer before repair, recoating or replacement is required.
Outdoor metalwork is regularly exposed to rain, humidity, temperature changes, chemicals, sunlight and public use. Handrails, barriers and street furniture may also experience repeated contact and impact.
A thermoplastic coating can provide a durable finish while protecting the metal beneath. It may combine corrosion resistance, impact protection and relatively low maintenance requirements.
Service life still depends on correct specification and application. Damage, poor pretreatment or exposure beyond the coating’s intended limits can reduce its effectiveness.
Better Appearance and Product Identification
Many coatings improve appearance while also providing functional protection. Colour, gloss and texture can be controlled to create a consistent finish across individual parts or production batches.
Colour may also identify product ranges, mark safety equipment, match surrounding structures or support branding.
Metal stadium infrastructure provides a good example. Although the seats are commonly made from plastic, the surrounding system includes metal mounting points, support frames, rail systems, guardrails and barriers.
Powder coating can give these components a consistent finish while protecting them from weather, impact and frequent public contact.it’s also more attractive and tactile than cheaper alternatives such as galvanising.
Moreover, powder coatings can be used as a straight alternative to galvanising and plating, or in addition to these coating systems creating a robust coating system that significantly enhances both appearance and longevity. Plastic Coatings has coated rail seating systems used in safe-standing projects at major football grounds.
Improving Component Performance with the Right Coating
Plastic coatings can improve metal component performance by changing the properties of the exposed surface. They may provide corrosion protection, resist wear, reduce friction, insulate electricity, withstand chemicals or make the component safer and more comfortable to use.
The coating must be selected around the component’s material, design and operating environment. Pretreatment, film thickness, masking and application quality also influence how the finished system performs.
Plastic Coatings Ltd offers thermoplastic, powder, electrophoretic, PTFE, bonded lubricant and plastisol coating processes, together with in-house pretreatment. Speak to the team to discuss the component, its working conditions and the performance required from the finished coating.
