The PPA 571 coating protect metal fencing from corrosion for 15 years

Powder Coating vs Electro-coating

Posted on: July 11th, 2018 by byersbushblog

What is the right choice of finishing? When we consider the various technological advancements that have been introduced into the industry in recent years and the multiple options that are open to you, choosing the right finish can be quite difficult to do. However, for many customers, the choice seems to boil down between powder coating and electrocoating or sometimes referred to as E-coating. Take a look which method would suffice your preference.

Electro-coating Overview

When a service provider offers you electric painting, electroplating, or electrophoretic coating, all of these equate to electrocoating. This process is quite similar to the popular powder coating process in the context that the substrate is coated with an organic finish. The difference is contained in the method of transfer applied for both products.

In electrocoating, the substrate will be submerged in a bath that is a mixture of epoxy (or any other water-based solution) and paint. The particles suspended in the liquid solution will be attracted to the surface of the substrate with the help of an electric current. This method known as electrodeposition will be continued until the desired thickness of the coating is reached. The thickness can be increased or decreased by regulating the level of the electric voltage used.

Electro-coating

Once the substrate has been coated it will be moved to an oven for proper curing and institute cross-linking. There are four distinct steps that E-coating goes through:

  1. Pretreatment
  2. Electrocoat bath
  3. Post rinses
  4. Oven baking

The electrochemical oxidation process ensures that the special liquid paint will adhere to the surface of the material and create a proper finish.

Powder Coating Overview

E-coating is generally categorized as a wet coating process, powder coating on the other hand is a dry process because it relies on the use of dry powder. The powder makes use of a combination of various curing agents and epoxy resins. Electrostatic energy is applied to the powder particles with the use of a spray gun. This allows the powder to stick to the surface of the material before it is sent to the oven for curing.

Curing can be applied for the primer as well as for the finishing step of the coating process. In this step, the powder particles will be subjected to immense heat that will cause it to melt. This starts a chemical reaction that will result in the desired final coat.

Usually the powder coating process will be done using a production line that will limit spoilage and increase efficiency. The thickness of the final coat will be dictated by the amount of dry powder that is applied to the surface of the material.

powder coating

Advantages and Disadvantages of Electrocoating

It is undeniable that electrocoating presents some distinct advantages and disadvantages when properly applied. Since the paint is already deposited during the application, this creates and insulation and when electrical current is applied, the paint sticks to areas where it has not adhered to before.

Some say that this results in an even finish, but, with the resulting ultra thin layer of paint, there are some issues with corrosion resistance as well as the durability of the coat. E-coating also lacks the UV resistance that powder coating presents so there is a need to apply an added layer of protection once the baking process has been completed. Normally, that added layer of protection is done using powder coating.

Despite these disadvantages, electrocoating is still a highly recommended process because many service providers believe that it can deliver the quality finish that many customers demand. As far as materials and finishes for various applications is concerned, E-coating can present a number of positive options that will result in highly desirable finishes that is comparable with what powder coating can deliver.

Using Electrocoating

When will you know if it is better to choose e-coating over powder coating? Normally, e-coating can be a better option if the products to be coated present areas that can be difficult to reach. Electrocoating becomes a better alternative because of the immersion process that the material undergoes. This gives the liquid the chance to sneak into the hard to reach areas and deliver a thorough distribution of the coat, which may not be as easy to do when using a spray gun.

E-coating is likewise more desirable if the required coat is only a thin one because powder coats usually result in thicker coats. Regulating the thickness level is also easier with e-coating because you only need to regulate the level of the electric voltage being used.

The ability to regulate the thickness is important in some industries like the automobile market. In fact, often an e-coating will be used for the application of the primer coat and will be topped off by liquid painting to deliver corrosion protection for the treated material.

Corrosion Resistance

If protection from corrosion is an important factor in the selection of a finishing coat, there really isn’t much difference between powder coating and electrocoating. This means that despite the difference between the two processes, the focus should be on the formulation properties rather than the manner of application of the coating.

Corrosion Resistance

Both powder coating and E-coating can make use of epoxies, which present amazing corrosion resistance properties and can deliver an extremely durable finish. When used with powder coating, the finish will be thicker than that of E-coating, which can be better for some applications, but not for others. Epoxies used in powder coating also possess higher crosslinking properties compared to application with electrocoating, which delivers stronger resistance against chemicals, making it ideal for industrial applications.

When compared to a polyester powder coating, an epoxy electrocoating will present higher corrosion and chemical resistance. This may lead you to conclude that E-coating would be a better solution than powder coating. However, this conclusion would be inaccurate because the difference in the resulting resistance cannot be attributed to the coating process, but rather to the choice of formulation used. So if you use epoxy for both powder and E-coating, you may find that the resistance will still be better with a powder coated finish.

Powder Coating vs Electrocoating

Finally, when we take into account the aesthetics, durability, and sustainability of both coating processes, powder coating can deliver a harder finish. The manner of application and curing for powder coating also creates an unmatched weather ability, excellent hardness, better gloss retention, increased humidity resistance, and better protection against UV rays.

If we look at the overall performance, many service providers can attest to the fact that powder coating has been proven over and over again to fair better than other types of coating when dealing with exterior finishes.

To make sure you get the best from powder coating, get in touch with Byers Bush Powder Coating now!

Comments are closed.