What you need to know about amine blush: the invisible enemy of epoxy resin

Amine blush is a common problem when working with epoxy resin, but what exactly is it and how can you prevent it? In this article, we explain all about amine blush so you can get started on your epoxy project without any worries.

What is amine blush?

Amine blush is a chemical reaction that can occur when epoxy resin hardens. It occurs when the amine components of the resin react with moisture and carbon dioxide from the air. This reaction results in a thin oily residue on the surface of the cured epoxy. Amine blush is often barely visible, but it can cause problems during further processing of the material. Amine blush is also called 'snake skin' because the appearance of amine blush sometimes resembles the skin of a snake.

Why is amine blush a problem?

Amine blush can cause several problems when working with epoxy resin. Some common problems are:

• Adhesion problems: the waxy layer created by amine blush can prevent new layers of epoxy, paint or other coatings from adhering properly to the surface. This can lead to peeling, blistering or other damage to the finish.
  
  
• Aesthetic problems: Amine blush may be visible as a dull haze on the surface of the epoxy which can detract from the appearance of the final product. This can be undesirable, especially with transparent or colored epoxy.
  
  
• Interference with curing: in some cases, amine blush can disrupt the curing of the epoxy, preventing the material from reaching the desired strength and hardness.

How do you prevent amine blush?

Amine blush can happen to any epoxy user. Fortunately, there are several ways to prevent or minimize amine blush when working with epoxy resin. Here are some tips:

• Work in a controlled environment: amine blush is caused by the reaction of the resin with moisture and carbon dioxide from the air. By working in a room with a stable temperature and humidity and good ventilation you can reduce the risk of amine blush. If necessary, use heat mats, heat lamps, radiant heaters or food dehydrators to keep the temperature and humidity of the room constant. 
  
  
• Pay attention to the processing time: amine blush usually occurs during the curing of the epoxy. By processing the resin quickly and efficiently, you can minimize the time the resin is exposed to the air and thus reduce the chance of amine blush.
  
  
• Using a heat gun during curing: do you see amine blush forming during curing? Then it's not too late to do something about it! As long as the epoxy is still hardening and still in the 'gel phase', you can still remove amine blush by heating the epoxy. Many people use a heatgun for this. Move the heat gun over the surface to slowly heat the epoxy. Be careful that the epoxy does not get too hot. If you start to see bubbles, stop using the heat gun immediately. If the epoxy gets too hot, it will burn. In the video below, Ivo from Epoxytips.nl shows how to remove amine blush.   

How to remove amine blush

Are you dealing with amine blush on your epoxy project? Don't worry, it is possible to remove the blush and still achieve a beautiful end result. Follow these steps to remove amine blush:

1. Allow the epoxy to cure completely.
   Wait until the epoxy has completely hardened before removing the blush. Removing amine blush from an epoxy that has not fully cured can damage the surface. So please be patient.
   
   
2. Clean the surface.
   Use a cloth or sponge with warm water and mild soap to gently clean the surface of the epoxy. This will remove the waxy layer from the amine blush. Then rinse the surface well with clean water and let it dry.
   
   
3. Sand the surface.
   To ensure good adhesion of any subsequent layers, it is important to lightly sand the surface of the epoxy. Use fine sandpaper (220 grit or higher) and sand the surface evenly. Then wipe the surface clean with a damp cloth and let it dry.
   
   
4. Apply subsequent coats.
   After removing the amine blush and preparing the surface, you can apply any subsequent layers such as paint, varnish or a new layer of epoxy.

More tips or information about amine blush?

Amine blush can be an annoying problem when working with epoxy resin, but with the right knowledge and precautions it is possible to prevent or solve this. By choosing a low blush epoxy resin, working in a controlled environment and properly preparing the surface, you can enjoy a beautiful end result without worrying about amine blush.

After reading this article, do you have any questions about amine blush, epoxy or another project? Please feel free to contact our specialists. We are happy to help you!