Quite simply, coatings and finishes are a protective layer put on a component, sometimes for decorative reasons. Their primary function is to protect components from things such corrosive liquids, weathering or simply just damage. Acting as a barrier they stop the components base material from being compromised. Carbon steel, for example, is prone to rusting, so a coating or finish helps inhibit this from happening. The choice of finish applied is mainly dependent upon end use application, and Whale Engineering is well placed to provide advice and assistance as part of the design and production process subject, of course, to end use application.
Coating processes provided by Whale Engineering include:

  • Plating

  • Blackening

  • Passivation

  • Anodising

  • Galvanising

  • Powder Coating

  • Wet Painting

Plating
Using a variety of different materials, plating serves to add an extra layer to a part or assembly to not only improve its characteristics in terms of wear and corrosion resistance, but in may instances to enhance its decorative look. Materials used by Whale Engineering are:

  • Nickel

  • Chrome

  • Zinc

  • Tin

  • Copper

  • Silver

  • Cadmium

Each material obviously has its own characteristics and Whale Engineering guides customers in terms of the correct finish dependent upon specific needs.
Blackening
Often undertaken in batches, blackening is a cost-effective method of applying a thick matt black coating that helps prevent light reflection, whilst increasing resistance to wear and corrosion. Whilst resistance to the latter is fairly weak, it can be increased by being impregnating the coating with oil or wax.
Galvanising
Here zinc is applied as a protective layer to materials such as carbon steel and iron to protect against rusting. The components are dipped into a pool of molten zinc to create a matt silver coating on the part to protect it from mechanical damage.
Passivation
This more decorative method of protection is commonly used when plating zinc/nickel. It serves to reduce chemical reactivity on the component’s surface, and when used on stainless steel it removes free iron to help in the prevention of rust. End colours of yellow, blue, green and clear are the most often achieved.
Powder Coating
A popular dry finishing process, this method uses pigment and resin powder that are electrostatically charged. The part that is being coated is sprayed grounded, which means the particles attract to the part to create a coating. A curing oven is then used to melt the particles and secure the coating. It is very similar to painting, although it produces a more durable finish.
Anodising
Similar to the plating process, anodising is used on aluminium and its alloys. Creating an oxide layer on a component to a specific thickness, anodising delivers improved surface, wear and corrosion resistance. It is often used as a decorative method where a natural metallic appearance is required.
Wet Painting
The most common coating finish is painting. With an infinite number of decorative colours available, it is most commonly used on carbon steel components to prohibit weathering and eliminate rusting. It is, however, susceptible to chipping and therefore not a very durable coating.
Many of the above processes are done in two methods: Electroplating and Electroless. Where the requirement is for one metal to be deposited onto another, electroplating is traditionally the most commonly used method. With this process an electrical circuit is created using a cathode, anode and an electrolyte solution. The circuit created deposits atoms from the anode -the plating material – onto the material that is being plated, the cathode. It is a process that allows significant control over the thickness of the material deposit being applied.
Increasing in popularity is Electroless. With this method, components are dipped into different solutions to achieve the desired coating. The first stage of the process sees the component cleansed using and alkaline cleaner before being rinsed with water. Once clean it is dipped into coating substance, the process being repeated until the correct thickness of coating is achieved. It is often used for components where a thicker and more substantial coating is required.
Each coating is strictly examined to make sure there are no weak areas and that the correct coating thickness has been achieved.
CONTACT US FOR MORE INFORMATION