Here’s the crazy thing about amine blush. You don’t know what to call it until someone tells you that’s what you’ve got.
No one hardly ever searches for ‘what is amine blush’? Instead, resin artists search for
*Why is there a waxy, greasy film on my resin surface?
*Why is there a haze on my resin?
*Why does my resin coating have cloudy streaks?
*Why is my resin milky?
*Why does my resin have yellow, sticky spots?
Yep. You’ve got amine blush on your resin surface.
So what is amine blush?
Amine blush is a film that forms when the amines in epoxy hardener (part B) react with water and carbon dioxide in the air. The result is a greasy haze that settles on the epoxy resin surface.
Sorry for the high school chemistry flashbacks.
Why does amine blush happen?
When you mix resin and hardener together, the resin mixture gets warm. If it didn’t, your resin wouldn’t harden. And you’d be searching for reasons why your resin didn’t cure.
Now here’s the crazy part about resin curing. The thinner the epoxy layer, the less heat it produces. With less heat, the reaction is slower. A slower reaction gives the amines in Part B more opportunity to react with the water and carbon dioxide in the air. (What you really want is for them to react with the components in the Part A epoxy.)
Side note —
I tried finding an easy-to-read article about substance mass, r,eactions and heat production. Instead, all I found were a bunch of algebra equations and a bunch of big words that would take me all day to Google.
But I did find this little gem about the thermodynamics of cooking meat on a grill.
Why doesn’t amine blush happen every time?
It happens when there is a lot of moisture in the air. The higher the humidity, the more likely amine blush is to happen.
It’s also affected by your crafting area’s dew point. If the air is close to the dew point, moisture is more likely to come out of the air and settle on your epoxy surface.
Good news —
I did find an easy-to-read article explaining dew point.
And I saved a lot of money on my car insurance.
How do you fix amine blush?
Once the resin is fully cured, wash the surface with soap and water. Use a coarse scrub pad or stiff brush to help remove the amine blush. If you don’t have soap, you can also use denatured alcohol. Make sure your soap is completely removed from the surface. Otherwise, your amine blush might be gone, but a new resin layer won’t stick to the soap.
To be sure all the amine blush is gone, you can lightly sand the resin. Then, recoat with a new layer of epoxy resin.
What happens if I don’t do anything to fix the amine blush?
The haze will stay there, meaning your epoxy won’t have a glossy finish. Plus, new resin layers won’t bond to the layer with the blush. It’s also sticky, so it will attract dust and hair.
Especially cat hair.
What can you do to prevent amine blush?
1. Craft in an area that can maintain a low 70s F temperature. Not only is it essential that your resin area is warm but it needs to keep that warmth. You may have to run a heater during your cold-weather resin crafting months.
2. Lower your area’s humidity. You can do this by running a dehumidifier.
3. Don’t pour resin over a wet surface. Duh, right? But this applies to wood and other surfaces that might be retaining water.
4. Don’t add more hardener than the directions say. You’re adding extra amines to your surface, which can react and make blush. Plus, it can make your resin overheat.
A little note about amine blush: I live in Florida, where it’s humid 24/7/365. I’ve only had amine blush happen a few times. I tell you this so you don’t freak out that you have to live in the desert to make art with resin.
Like making resin mistakes?
Me neither. Except when I started creating with resin 17 years ago, that was the only way to learn. That’s why I wrote the ebook Resin Fundamentals. Instead of wasting your time and resources, you can take the easy option. I’ve condensed my knowledge into a PDF book you can read this afternoon. Buy now, and the book is yours to download in minutes.
Unpublished Blog Posts of Resin Obsession, LLC © 2023 Resin Obsession, LLC
I have a large coffee table with 2 perfect coats of resin sitting on my dining table,it has been there 4 weeks waiting for humidity to drop to ? under 70% so I can do final layer. I dont have a dehumidifier but will it help if I put my air con on or lots of fans?
I am getting impatient to do final layer but it is a beautiful creation i think and I would cry if I got amine blush on final coat.
Hi Julie, it’s humid here where I do resin art too. I haven’t had a problem provided the temperature is warm enough (70’s F or above).
I have been making jewellery, when I dome the pendants, they appear scratched or cracked, when I try to polish them they are slightly tacky. Is this amine blush? Thx
Hi Sam, it doesn’t sound like it. Amine blush is usually greasy, not sticky.
Hi! Is it possible to clean stubborn amine blush on a finished and framed piece? The piece I resined a couple of weeks ago (the painting was cured 5 weeks) recently developed what looks like a greasy haze after I framed it today. Can amine blush grow if the piece was moved to a more humid environment? I’ve tried soap, lacy, acetone, goo gone, oil, baking soda, vinegar and even a magic eraser – on a test piece with the same problem. Nothing has removed it. It is a commission that I’ve been working on since January 😩. It’s all ready to go and then this happened.