1K Coating 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. Here are some brief definitions that we hope will dispel the confusion.

1K Coatings

This is a term used to describe a coating that does not require a hardener, catalyst or activator. This term can be used to describe “single-component” paints that dry in the air (whether latex house paint, or old school lacquer) and nearly all aerosol spray can paints. The 1 Shot sign painters pinstriping paint we sell is 1K enamel.

2K Coatings

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.

Single Stage Paints

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

Two Stage Paints

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.