Coal Tar Epoxy 

A Strong Protective Coating for Steel and Concrete
Coal tar epoxy is a kind of coating that is made by mixing epoxy resin with coal tar pitch. This creates a strong barrier that protects against water, chemicals and corrosion. That is why coal tar epoxy is often used in painting and protective coatings especially when steel or concrete is going to be in contact with water or buried underground.

What is Coal Tar Epoxy?

Coal tar epoxy combines the sticking power of epoxy with the waterproof and chemical-resistant properties of coal tar pitch. This makes a coating system that's very good at:
Protecting steel from corrosion
Resisting seawater and freshwater
Working In underground and underwater environments
Handling chemical spills and harsh industrial conditions
Building a strong protective layer in just a few coats
Because of these properties coal tar epoxy has been a standard coating in heavy industry for a long time.
Common Uses

Coal Tar Epoxy

Coal tar epoxy is often used for:

1. Underground pipelines
This includes buried steel pipelines, water transmission lines and firewater pipelines.
2. Marine structures
This includes jetties, sheet piling and offshore splash zones.
3. Tank bottoms
This includes tank bottoms and underground storage tank areas.
4. Wastewater and sewage plants
This includes tanks, wet wells and chemical pits.
5. Industrial steel structures
This includes high-humidity process areas and corrosive industrial environments.
Main Benefits

Coal tar epoxy has benefits, including:

Excellent corrosion protection
Creating a strong barrier between steel and moisture
Very good water resistance
Suitable for use in water or underground
Building a strong protective layer in just a few coats
Strong sticking power
Bonds well to clean steel and prepared concrete
Good chemical resistance
Handles many industrial contaminants and salt exposure.
Limitations

Coal tar epoxy also has some drawbacks:

It only comes in a black color
It can break down in sunlight
It has a strong smell when it is being applied
The surface can change color over time
It can become brittle as it gets older
Many projects are now using newer epoxy systems because they are better for the environment.
Because it breaks down in sunlight it is not a choice for a decorative finish that will be exposed to the sun.
Preparing the Surface

To get the results the surface needs to be prepared:

For steel this means blasting it clean and creating a rough surface.
For concrete this means making sure it is dry and free of contamination.
Applying the Coating

Coal tar epoxy is usually applied using:

An airless spray gun
A brush for areas
A roller for touch-ups
A special spray gun, for large industrial projects.
Typical Application
The way to apply coal tar epoxy is to:
Apply a thin coat to the edges and corners first
Then apply a full coat
Check the thickness of the coating
Make sure it is fully cured before putting it in service.
Example Coating System

Here is an example of a coating system:

For a steel pipeline the surface would be prepared and then coated with coal tar epoxy.
The first coat would be a coat the second coat would be a full coat and the third coat would be a build coat.
The final thickness of the coating would depend on the requirements of the project.
Safety Precautions

When applying coal tar epoxy it is important to:

Use ventilation to remove the fumes
Wear a respirator with the correct filter
Wear chemical-resistant gloves
Wear eye protection
Make sure the air is safe to breathe when working in enclosed spaces.
Coal tar epoxy can contain chemicals so it is very important to use protective equipment and ventilation.
Coal tar epoxy is still one of the heavy-duty industrial coatings.
For buried steel, wastewater facilities and underwater service it provides corrosion resistance and excellent water protection.
While some projects are now using coatings, coal tar epoxy is still widely used in many industrial maintenance projects.