What is the difference between 1K and 2K Aerosol Spray Paint?


When choosing the right Spray Paint for your project, not only it is important to know the difference between 1K and 2K aerosol cans but also to understand the use of the hardeners which are required to cure 2K paint.

A 1 pack paint does not require an activator to cure so it usually requires less drying time, however the final coating is not as hard wearing and resilient as a 2 pack paint which does require an activator (hardener) to cure but in general takes a longer period of time to dry. However, it does provide the most resilient final coating.

It is important to note that most traditional 2K hardeners are Isocyanic based and are sold widely as 2 pack paints. This type of hardener used in the traditional 2k or 2 pack paints includes compounds which are harmful to both humans and animals, and are known to cause cancer and other serious respiratory illnesses. This means that these paints should only be used under the strictest health and safety conditions, the label should always state “for professional use only” and bare the correct symbol of skull and crossbone. Its use should always be after the proper training and with the correct equipment as you can cause harm to yourself and others around you.

Isocyanate Hardener vs Non-Isocyanate Hardener

The traditional 2K or 2Pack Aerosols that come with the Isocyanate Hardener use a ring pull/button (or similar), which is usually attached to the lid and that is used as a tool on the base of the can to pull and twist the release of the hardener. Some providers use slightly different variants, but the self-contained hardener is released in the same way.

From the release of the Isocyanate Hardener, the paint has a shelf life of up to 4-8 hours of use, which can be a major hassle if you have to use multiple cans for the job over a few days. This can also affect the quality of your finish if the hardener is not fully released or if the mechanics of the canister fail.

Before release, the Isocyanate Hardener inside the can has a maximum shelf life of 12 months, beyond that point the compound begins to change and decrease. So, unless you can be assured of the date the can was manufactured (and not sat on a shelf for months), then you run the risk of purchasing a “new” product with an out-of-date hardener inside which, of course, is a recipe for disaster.

As the importance of health, environmental and cost issues have become a real concern for many industry professionals, coating companies and now homeowners, we ensure that all our 2K paints use a Non-Isocyanate Activator or hardener.

2K Aerosols with Non-Isocyanate Hardener also known as 2K ADC (Air Dry Converter), use a non-isocyanate based hardener to convert conventional 2k force dry paint and materials into air dry materials without losing any of the full benefits of this most versatile paint. The 2K ADC paint is for customers who require 2K or 2 pack paint and materials without the health concerns associated with Isocyanates.

In addition, with the Air Dry Converter the spray paint benefits from improved drying times and provides a usage time of at least 12 months, which becomes much more economical at volume levels.

So in summary, you have a choice when buying 2K paint in Aerosols: A product with a slightly faster drying time, but with major health risks and a maximum of 8 hours usage time or, a product with a slightly slower drying time, with no health concerns, and which is much more economical as each can has a usage time of at least 12 months, if cleaned and stored correctly.

It is important to note for anyone carrying out spray painting, whether professional or not, the importance of using the right equipment such as protective gloves, masks and breathing apparatus, and to ensure that health and safety protocols are being followed to provide a positive spraying experience.

The 2K can is a superior product that is recommended by professionals when application is intended for an exterior surface. 2K provides durable protection against environmental exposure with a harder wearing, smoother finish, and an improved resistance to oil, petrol, scuffs & scratches.


We can supply both types of 2K cans, however we always opt to provide the safer Non-Isocyanate version unless specifically asked not to.

We do not sell the traditional cans through the website as this is open to public and trade so, if you require the traditional 2k cans please contact us directly at customerservice@yourspraypaints.com


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