Surface finishes FAQs

From utility- and functional-grade to commercial- and consumer-grade coatings—including decorative finishes—there are numerous surface finish and plating options to choose from for your next project. Before selecting a surface finish for optimal part performance, make sure you are informed about the benefits, process and cost of each option.

We have compiled a list of frequently asked questions about surface finishes from our webinar, Surface Finish 101. If you would like to learn more about surface finish options and best practices for selecting an effective surface finish, register for the full webinar or explore the Dynacast Finishing Selector.

What materials can E-coat be applied to?

E-coat can be applied to almost anything, including aluminium, zinc, magnesium, steel and more. It is a highly robust finish.

What does PVD stand for?

Physical Vapour Deposition. PVD is a batch process involving a controlled explosion, in which the target metal is vapourised and transferred to the component surface. To use this process, the part must first be chrome-plated, and all liquid must be removed from the part. It is a very expensive process, but a wide range of colours is available. Its physical properties are exceptional, and it is extremely durable; however, every aspect must be precisely controlled to achieve the desired effect and avoid damaged parts.

What is the best pre-treatment for preparing aluminium castings?

Shot blasting aluminium castings before finishing is most common. E-coating would be an excellent economical operation. Chemical film is another treatment. It acts as an excellent primer for wet-coat finishes on aluminium.

What do salt spray hours mean in real-world applications?

There is little evidence indicating a positive correlation between salt spray hours and what will happen to a given part over time in the real world. Typically, for automotive interior parts, around 48 hours is considered. However, for exterior applications under service conditions, it can be up to a thousand hours. There is also copper-accelerated acetic acid salt spray (CASS), which simulates a lifetime of use in a short period. CASS differs from natural salt spray.

How much material is removed during the shot blast process?

During the shot blast process, the surface of a part is peened; no part material is removed or lost. This process is typically used to soften parting lines or eliminate sharp edges that could affect line workers during assembly. It can also be used to provide a uniform finish.

Is black plating different from chrome plating?

No. Chemical companies have developed a variety of methods and chemicals to turn a typical shiny chrome finish into what is known as black chrome or black nickel. You can achieve that black chrome appearance with chrome plating. Other colours, such as indigo chrome, are also available. However, not every chrome plater offers black or coloured chrome, so it is generally more expensive than bright chrome.

How does E-coat differ from powder coating?

E-coating is a dip process; powder coating is a spray process. E-coating is much more fluid and can reach all corners and pockets of a part, whereas powder coating can sometimes be less effective in this respect. E-coating and powder coating are both rack processes. With e-coating, the entire rack is dipped, whereas rack design and placement are more important for powder coating to ensure equal coverage on all sides of a part. Often, especially for exterior applications, a part is e-coated and then powder-coated.