1K Coatings vs. 2K Coatings


There is often confusion and misuse of terms when it comes to describing automotive coatings. Not only do some people not know the difference between 1K and 2K paints, but some people confuse single stage paints and two stage paints with 1K and 2K. The way the coating is applied such as through a pain gun, aerosol, or even brushed on doesn’t dictate if a coating is 1K or 2K. Here are some brief definitions that we hope will dispel the confusion.


1K or single component coatings describe a coating that does not require a hardener, catalyst or activator. This term can be used to describe “single-component” paints that dry when exposed to the air (whether latex house paint, lacquer, etc.) and most aerosol spray can paints. For instance our Rust Encapuslator Platinum is a 1k Coating that dries and is an extremely durable coating.


This describes a coating that needs to be mixed with a hardener, catalyst or activator. Once it hardens it is much less susceptible to damage from chemicals, weather, or UV rays. 2K paints includes all of our Eastwood automotive single stage and base coat/clear coat finishes, “two-component” paints and other urethane finishes. Eastwood’s 2K Aero-Spray paints combine the convenience of an aerosol and the durability of a 2K paint (the activator is in a separate compartment).
NOTE: Typically the term “catalyst” (as in epoxy catalyst) is used separately from the terms “activator” and “hardener” because a catalyst does not have isocyanates.


Used to describe a coating that does not require a clear top coat. A single-stage coating can be 1K or 2K, with or without a catalyst, hardener or activator. Plus, a clear top coat may be used in many cases for enhanced durability or depth. You can still get many nice finishes in single stage paints like this.


Describes a coating system that requires both base and clear coats. This is more commonly referred to as “basecoat/clearcoat” or “BC/CC”. Most base coat/clear coat systems are also 2K coatings, but not all of them are. The base coat provides the color and coverage, while the clear coat, like the Eastwood Premium Show Clear, provides all the gloss and protection. Base coats generally NEED a clear coat to protect the base coat. A satin or matte clear coat can be used for a lower sheen level on base coat clear coat paint jobs.

You can find all of our automotive paints or coatings for everything from a driveway paint job to a full blown professional paint job on our site HERE: https://www.eastwood.com/paints.html

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