Resin can be a fussy beast. Like on a scale of changing a light bulb to growing orchids, resin is in the changing a tire range. It’s pretty straightforward, but leave something out. Or cut a corner. Or, as in this case, fail to follow good procedures, and your resin time suddenly turns into a blowout. While resin getting hot is normal, it shouldn’t get hot and cure quickly (unless it’s a resin designed to do that). So when my epoxy resin overheated and cured in its cup in about 90 seconds, I turned it from a mistake into a teachable moment. Here’s your chance to learn and keep it from happening to you.
Let me set the stage:
After warming my resin kit, I mixed three ounces of Resin Obsession super resin to pour into three separate resin molds. I poured the first two projects, but by the time I tried coloring the resin for the third project, it started smoking. Within a minute, the resin got super hot and fully cured.
And if you’re thinking, ‘What’s the big deal? I’d love for my resin to cure faster!’
It’s because that resin cures full of bubbles and is unusable. Like this…
So why did the epoxy resin overheat?
There are several reasons why my epoxy got hot, smoked, and cured quickly.
Factor #1: Resin kits have a minimum and maximum mixing amount.
A minimum mixing amount ensures enough heat is produced to start resin curing, but there can be too much of a good thing. When you go above the maximum mixing amount, the resin heats up too quickly. I mixed three ounces of the Resin Obsession super clear resin, which is the maximum mixing amount for this resin.
Factor #2: While warming resin is excellent for reducing bubbles, that heat also adds to the heat of the reaction.
While I usually warm my epoxy resin in a hot water bath for five minutes, I went a little squirrel and got distracted. My resin sat in hot water for at least ten minutes before I used it.
Factor #3: It was 80 degrees F inside my studio.
I live in Florida, so I had the windows open to allow for cross-ventilation. (an important part of resin safety)
Factor #4: Heat builds on itself
The more resin and hardener you mix, the quicker the reaction heat builds. I only used about 1/2 ounce of the 3 ounces I mixed in my first two projects and let the other 2 1/2 ounces sit in the mixing cup, producing heat. For bonus points, you can read about thermodynamics and the science behind this.
So what did I do wrong that my epoxy resin overheated — and what should I have done differently?
1. Even though I didn’t mix more than the maximum mixing amount, the extra heat from the resin sitting in the hot water bath too long added too much heat to the reaction. I should have paid closer attention to the amount of time the resin sat in the water instead of multitasking.
2. I didn’t consider my room temperature. I should have turned on the air conditioner or waited until later in the day to pour resin when things were cooler.
So what should you do in case you find your epoxy resin overheated?
Situations like this are why I always recommend having excellent ventilation when working with resin.
In my case, I work underneath a ventilation hood, plus I had the benefit of airflow from the open windows. At the least, you should have air circulating to allow the fumes to move away from you in a case like this.’
Even though my cups got very hot, they didn’t leak, melt or crack. You can’t always count on that with other paper or plastic cups. Worrying about resin smoking is bad enough. You don’t want to worry about the cup leaking resin everywhere.
Have a metal container handy when you are mixing resin.
If your resin overheats and smokes, you do not want to put it into a plastic or cardboard container. These can leak or, worse — catch fire.
Do not throw the hot resin in your trash!
The reaction is still occurring and can melt your trash can or start a fire. Instead, take it outside, where it can sit on a surface while things cool off. In my case, I walked 10 feet through the front door and set my smoking hot resin on concrete to cool off.
Have a fire extinguisher close by.
While this is the worst-case scenario option, it never hurts to be ready should you find your epoxy resin overheated.
Want to see more about what happened? Enjoy a close-up of the bubble-filled, overheated epoxy resin mess:
Want to learn more of the resin basics, so this and other mistakes don’t happen to you?
Be sure to grab your copy of the instantly downloadable PDF book, Resin Fundamentals. The book gets you to resin expert status in only a couple of hours, even if you have never worked with resin before. Buy now, and the ebook is yours to read in minutes.
Unpublished Blog Posts of Resin Obsession, LLC © 2023 Resin Obsession, LLC