I was having curing issues with the polyester, polyurethane, and epoxy resins I use when casting resin in my garage during cold temperatures. I realized it was all around the heat or lack thereof during the complete curing process. It would start fine as the heat built up. But, once the warmth began to dissipate, that’s when the problems would start. So, if you are asking yourself how to get your epoxy to cure in cold weather, here’s what I do.
These are two-part sphere molds I make myself.
I heat whichever resin type I’m working with in a water bath. I want to get the resin to about 77-80 degrees F when I’m ready to pour.
After I pour the first base layer into my silicone mold, I cover it with a container. This seals any dust from entering and retains the heat as the exothermic reaction occurs.
After I add the second layer, I cover the mold again to let it cure. But before I cover it, I activate a HotHands hand warmer about 15 minutes before the final epoxy pour, so it gets up to max temperature, which is super important in cold weather. Then, I place it next to the mold and cover it with a container.
I put some weight on top to help retain heat and prevent dust from getting into the resin.
This technique has not only improved the quality of the castings but has also dramatically cut down the cure time.
I’m a night owl, so I generally cast late. Before using the warmer during curing, if I returned about 12 hours later, the resin would still be sticky and not ready to handle. Using the HotHands and sealing the mold from the 55-60 degree working temperature in my garage during the winter months, all of my castings have come out perfect and cured FAR quicker.
I’ve been casting for a while now. Moving forward, this will be my method when my garage is under 70 degrees F. I’ve used this process with fourteen different epoxy, polyester, and polyurethane resins and gotten better results every time.
This shows how my epoxy castings came out in cold weather before using the heat pad. It’s a night and day difference!
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Originally written Jason Bell of Ballistic Impressions
Unpublished Blog Posts of Resin Obsession, LLC © 2022 Resin Obsession, LLC