Thanks to Jason Bell of Ballistic Impressions for sharing this tip.
I was having curing issues with the polyester, polyurethane, and epoxy resins I use when casting during this time of the year in my garage. I realized it was pretty much 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 resin to cure in cold weather, here’s what I do.
Take my “Bullet Spheres” for example. These are made with a two-layer pour in 2 part molds I make myself.
I heat whichever resin type I’m working with in a water bath. I want to get it 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 off any dust from entering and retains the heat as the exothermic reaction takes place.
After I add what I embed/pour in the second layer, I cover the complete mold to let it cure. But before I cover it, I activate a HotHands hand warmer about 15 minutes before the final pour so it gets up to max temperature. 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, etc. from getting into the resin.
This technique has not only improved the quality of the castings, but it 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 came back about 12 hours later, the resin would still be sticky and not ready to handle. By 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 since have come out perfect and cured FAR quicker.
I’ve been casting for a while now. This is going to be my method moving forward 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 castings were coming out from curing in cooler conditions versus using the new method. It’s a night and day difference!
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What other questions do you have about how to get your resin to cure in cold weather?