What is it?
This is an issue known as “Epoxy Bloom” more commonly known as “Amine Bloom”, often identified by a white, waxy surface on top of the coating.
Common Causes:
Moisture – This is the most likely cause of bloom and is generally due to the introduction of moisture during the cure process. If the epoxy meets any moisture/humidity/condensation/dew, this can cause the epoxy to bloom during the curing process causing a patchy surface.
Other external processes such as gas space heaters can also introduce moisture.
Reaction with substrate - This can happen due to the ammonium bicarbonate salts reacting during a change in humidity and temperature as the epoxy is curing, causing them to rise and form a white/waxy surface.
Although bloom generally will not affect an epoxy coatings durability, the surface will look very patchy, almost like a worn floor, which we understand is not appealing.
So, how would I resolve this?
- A re-coat with one further coat to provide a uniform coat across the full surface would be the best recommendation.
- If the coating has been down for more than 48 hours, you will need to gently sand the surface with a fine/medium grit sandpaper to create a mechanical key, ensuring all debris is removed upon sanding.