Frequently Asked Questions:

How much does it cost to utilize/apply electrocoat?
Electrocoat is one of the most cost effective technologies available due to its high transfer efficiency, ability to densely load parts on the production line, and automated process.  There are a number of variables that contribute to the overall cost of an electrocoat system based upon part design, production rate, etc.  It is recommended that potential users contact both the pretreatment and electrocoat vendors to get an initial understanding of the cost.

What is the capital cost of a new installation system?
Although through more efficient line designs the capital equipment costs for installation of an e-coat system have been reduced throughout the last few years, electrocoat systems are typically significantly more capital intensive than other coating operations but offer the opportunity to quickly achieve the return on investment based upon the cost effective application.  Further discussions with equipment vendors can help a new potential user gain a better understanding of the capital cost based upon specific requirements for their application.

Is there a minimum annual production (e.g. square footage) that is required to successful run electrocoat?
Due to the higher capital cost of an electrocoat system typically it is recommended that customers have a minimum of 5 – 10 million square feet of production on an annual basis.  Some smaller systems can tolerate slightly lower production rates (e.g. 2 – 3 million square feet annually).

Can I coat different colors?  How many?
Electrocoat systems can have multiple colors.  Typically multicolor users will utilize the same pretreatment and cure oven for all colors with a separate e-coat tank and post rinses for each color.  In addition, customers can also utilize a single e-coat tank and transfer different colors in and out of the tank based upon their production needs.  The key issue is that the minimum thresholds need to be achieved for annual production.

Where do I find “experts” that can assist with design and building a system?
The Electrocoat Association has a number of different OEM vendors and consultants that can assist with the designing and building of a system.  In addition, for specific questions please contact The Electrocoat Association at 800-579-8806.

What certified programs does e-coat meet (e.g. UL, water storage, etc)?
Electrocoat products meet a number of different certified programs for various industries.  Please contact The Electrocoat Association and/or coating vendors on the website to determine which type of coatings meet your requirements.

What is the maximum film build that can be applied?
Majority of electrocoat products are applied between 0.5 and 1.2 mils.  For certain applications electrocoat as a single coat is capable of achieving 2.0 + mils.

How much floor space does e-coat take in my plant?
Depending upon the type of system utilized (indexing versus monorail) the overall footprint can  be relatively small versus other coating systems.  When smaller footprint systems are utilized the ware package (size of part) and annual production rate of the system can be constrained.  Monorail systems typically will require significantly larger footprint due to the longer pretreatment system typically required for e-coat along with the electrocoat tank and post rinses.  In addition, due to the automation of the electrocoat system line speed is generally faster than other coating applications which also creates a longer system due to dwell times required for various stages of the process.

How do I strip electrocoat from my parts?
Generally electrocoat requires less frequent stripping due to the application process and the insulating properties that are achieved when the coating is cured.  Racks for electrocoat are stripped in the same manner as other coatings through chemical stripping, burn off ovens, or blasting.

How does electrocoating protect steel from corrosion?
When coating professionals talk about electrocoating, they are talking about the complete process of surface preparation, coating application and paint curing.  This is also true of other commonly used finishing processes such as liquid painting, powder coating and even various plating and etching processes.  What makes electrocoating unique is the method of application for an organic coating material that is heat cured (Thermoset).  The electrocoating material is a coating that is applied to the surface by an electric current. This current will cause the coating to completely cover recessed areas and edges.  It is then heat cured to convert the material to a hard and durable film. The steel is protected from the elements by this hard and durable film.  The electrocoat forms and chemical and physical barrier.

What are the steps in the electrocoating process?
First, electrocoating is designed to be an efficient production process.  This is because of the equipment generally required to adequately support the process.  Parts or components to be coated are generally transferred to a conveyor, which is part of the coating system. Steel is the most common metal to be electrocoated.  For optimum corrosion protection and overall paint performance, the recommended pretreatment for steel is the zinc phosphate system.  There are some variations in pretreatment steps but here is a suggested sequence of the steps for the electrocoating process over steel: Alkaline Cleaner, Water Rinse, Water Rinse, Surface Conditioner, Zinc Phosphate, Rinse, Seal, De-ionized Water Rinse, Electrocoat Application, Permeate Rinse, Final De-ionized Water Rinse, and Cure Oven. 

Is there any environmental impact when using electrocoating?
Yes, but, with the proper design of the processing system and support equipment the electrocoating process will be in complete compliance with the most stringent environmental regulations of the United States Environmental Protection Agency. This is also true for the environmental regulatory agencies of states, municipalities and other countries. 

The coating material technology has advanced to the point where there are virtually no heavy metals or volatile organic compounds being released.  The waste treatment systems now available for the effluents from the pretreatment process can keep the release of materials considered to be hazardous at levels well below the regulatory requirements.

What is the difference between electrocoating and powder coating?
With electrocoating, a positive charge is applied to the paint bath and a negative charge is applied to the parts to be coated. The paint particles are suspended in water.  Also, the paint is a special formula that allows an electric current to travel from one paint particle to another until it reached the part where the paint particles electrically attach themselves to the surfaces of the part. The parts are then processed through a bake oven where the paint is melted onto the part for fusion bonding and then heat cured to form a hard and durable film to coat the part. The cured thickness of the electrocoating film is usually 0.6 to 1 mil.

Powder coating has many similar characteristics. However, the paint might be thought of as a plastic material in powder form.  The consistency is similar to baby powder or face powder.  The powder is sprayed through a gun that contains a charging mechanism. As the powder particles exit the end of the spray gun they receive a very high voltage (very low amperage) negative charge.  This charge is much like the electrostatic charge one might get when reaching for a doorknob after walking across a carpet.    The parts to be coated are positioned on a conveyor rack which is grounded.  As the highly charged powder particles approach the grounded parts they will be electrically attracted to the grounded part.  The parts are again passed through a curing oven where the powder particles will melt and fusion bond to the metal part then be heat cured to form a hard and durable film to coat the part.  The cured thickness of the powder coating film is usually 1 to 3 mils.

When do you use an epoxy vs. an acrylic electrocoat?
Most of the time we see electrocoating being applied for one of two reasons. As a primer for other top coatings or as a single protective coating for components.  Examples of the latter are under-body or under-hood automotive or other equipment components.  Epoxy will perform best for these purposes.  However, epoxy will form a chalk film on the surface if it is exposed to the ultraviolet rays from sunlight for a relatively short period of time.

When electrocoating is to be used as a single coating for products or components that are to exposed to sunlight for long periods then an acrylic electrocoating material should be used.  It will provide a high quality finish with very good protective properties.

Why would you want to paint over electrocoat?
Electrocoat does not always have to be top coated.  Often, it can work as a one coat final finish.  But, when paired with a top coat, the electrocoat acts as an outstanding anti-corrosion primer to liquid or powder top coats.  These top coats allow for a variety of color and gloss options that are not practival or easy to quickly change on an ecoat tank.

Can I specify how much electrocoating to put on the steel?
The normal electrocoating process will yield a dry film thickness or .6 to 1.0 mil.  There are materials available that are capable of applying a heavier film thickness and there is a two-coat electrocoating process available.  Unless the project has very large volume and a good reason for requiring a different thickness one of these options would probably not be economically feasible.

Can you electrocoat in bulk?
Bulk electrocoating has been used for certain parts with some degree of success.  The primary constraint is the electrical contact required in order deposit the coating on the substrate.  Some fastener components are using a bulk process. They may make contact on threads where the contacting surfaces are sharp and tend to heal from the contact.  However, they may also become attached and have to be separated.

Other examples have been small castings of complex configurations. One known application actually tipped the basket while in the paint bath in order to expose some of the contact points.

If the part configuration is such that flat surfaces can be in contact to protect each other from paint deposition then they would not be candidates for bulk coating.

Yes, it is possible to electrocoat in bulk but several circumstances would have to exist in order to make this a feasible and acceptable process.

How long will electrocoating protect my steel from corrosion?
This question can not even be estimated without more information.  For starters, it would depend on the conditions to which the coating is to be exposed, the process used and the material applied. 

Are there any special design & fabrication considerations required to make steel ready for electrocoating?
As with any process, there are design considerations.

  • First, consider how it will be racked on the conveyor.
  • Probably most important factor is drainage for pretreatment and coating operations. 
  • The opposite of drainage is air pockets that might be created during immersion in the paint bath. 
  • Will the component fit through the ware size window for the coating system where it will be coated?
  • When two plates are welded together with one overlapping another there can be problems with the interface.  Consider using one part with greater thickness instead.

Where are electrocoated products used?
This process is used for a wide variety of products. Where there is a need for exceptional coating performance over a metal substrate you may find electrocoating used as a primer or a finish coat.


Copyright © 2016 The Electrocoat Association, All rights reserved. Content and images may not be used without authorization from The Electrocoat Association

Powered by Wild Apricot Membership Software