What is amine blush and what is its effect on single-pack products?

What you need to know about amine blush

Amine blush is a waxy bi-product that appears as epoxy cures. It can prevent varnishes and other coatings from bonding.

What is amine blush?

After application and during the curing (drying) process, a solvent-free epoxy resin releases a blush to the surface called Amine Blush. This blush is known to appear as a wax-like film that sits on the surface of the cured epoxy resin. The appearance of the blush depends on the moisture in the air during the curing process, and is not always visible.

What is the effect of amine blush?

Amine blush will keep some subsequent products applied from fully curing, performing correctly, or cause yellowing unless removed properly.

How can I reduce amine blush?

The best way to reduce blushing is to work in warm temperatures (the epoxy sets up fast, reducing the blush window) and with humidity at low levels. It would be best to avoid conditions where moisture is coming out of the air as temperatures fall.

How do I remove amine blush?

Amine blush is water soluble, making it easy to remove. We recommend thoroughly washing the cured epoxy with clean warm water, all-purpose soap, and a stiff brush. Clean the amine blush off the epoxy before sanding as well. It is a safe practice to clean all types of epoxy resin, even if the label states that it is ‘amine blush free’ or ‘no blush formula’.

Please note: Aggressive solvents like Acetone will not remove the blush.

What will it do to my project?

If amine blush is present on the surface and not properly removed, you might not notice a problem with your project until after it’s completed. It can cause the finish to improperly cure or lead to detachment of both primer and finish.

In summary, always remove surface contamination, including amine blush, to avoid any problems with adhesion, drying or discoloring. After washing the epoxy surface, allow to dry prior to applying subsequent coatings.