Heated Epoxy Kicked Quickly

Hi all, I was doing an epoxy infusion in a cooler garage so I was heating up the mold and part A of the resin in a little heat box with a space heater. Both were around 50C which I had done before on a previous part. This part used more resin (880g total) and it just fit in my container. I felt there wasn’t enough room for the degassing froth so I separated it into two containers. The first degassed fine and when I put the second in the bubbles were quite slow as if it were thicker. About 4min in it started to bubble but it looked like it broke through a hard layer on top and then it started to smoke. I checked my first batch and it was also smoking/starting to cure in the container. On the previous parts (660g total resin) it took a good 45-50min to thicken up and this one was only about 18-20min in from being mixed.

Did I heat the resin too much before mixing?
Should I only heat the mold and not the resin for an infusion? I can keep the resin in the house at room temp until I mix it up if that would work better.

I’m a bit confused as I was under the impression that heat wouldn’t speed the cure on an epoxy. I can’t afford to lose this part if I try again and that happens during the infusion.

Any help or comments would be greatly appreciated. Luckily I get a second try.

Every 10 degree rise in temp will speed/double the curing rate and leave just half the time.

You are confused. Epoxies, polyesters, and vinylesters are all thermoset resins. They heat up during cure. Adding heat accelerates cure. Larger amounts of resin heat up more/quicker due to the exothermic reaction. All these things are working against you and you need to perform a balancing act to get the part done correctly.

Thank you for the feedback. I tried again just heating the mold and it worked like a charm. :slight_smile: