I like creating with epoxy resin all year long. Unfortunately, though, the weather isn’t always ideal. I live in British Columbia, Canada, where it is cool and rainy most of the year. So for most of the year, I have to plan ahead to have successful pours. I’ve learned a few things along the way. Today, I’m sharing my four favorite tips for resin casting in cold weather.
Resin prefers warm temperatures and doesn’t like excess moisture.
Resin that’s too cold is like molasses. While mixing the parts, no matter how slowly you stir, you’ll trap all sorts of bubbles. The thicker consistency also makes it challenging to combine the two components thoroughly. Since part of the curing process is a chemical reaction causing heat, a resin that’s too cold can have problems curing. Sometimes resin that cures soft and bendy cured at too cold a temperature.
Tip 1: Turn up your room temperature.
I can set the heat for a single room, so I’ll turn the thermostat up for my workshop and keep the door closed to trap that warm air. Turning the heat up in that room also helps to dry it out a bit, too. (Yes, this is how cold it is before I turn on the heat.)
Tip 2: Warm up your resin kit.
To warm up the resin, I give it a “spa day,” a warm water bath for 10 minutes. I have a salsa pot mini slow cooker which keeps the water warm. A bowl of warm water will work, but the water doesn’t stay warm the entire time. You can find a mini crockpot like this at kitchen stores or even use a potpourri warmer.
When I’m about ten minutes away from casting my resin, I put the bottles into plastic bags and then into the pot. I can put the bottles directly into the water, but it destroys the paper labeling. If I use liquid resin colors, I also put them into the pot with the resin.
Casting resin in cold weather also means I prepare any molds I plan to use. I am using this mold I bought on sale a couple of days before Halloween. Wa-Hoo!
⚠️ WARNING: If you use “food” mold for resin, do not use it for food after. Once you use it for resin, you should think of it only as a resin mold.
After the resin has warmed up, I take the resin out of the spa and make sure the bottles are dry on the outside. You don’t want to drip water into your resin.
Because I’m working with small volumes of resin in molds, I’m using the Resin Obsession super clear resin. If you aren’t sure which resin you should use for your project, check out our resin buying guide.
To measure the resin, I use two cups, making it easier to see how much I am pouring. The super clear jewelry resin is a 2:1 ratio two-part resin. In this example, I poured 2 drams of part A and 1 dram of part B. While you might think adding extra hardener is a good idea to help heat up the resin, don’t! Adding too much hardener causes problems.
Tip 3: Create a resin hot box.
Part of resin casting in cold weather also means I have a “hot box” to keep the air around the curing resin warmer than my room temperature for (at least) the initial part of the cure time. Simply having the air in the box warmer than the room air will help with curing. The hot box also does the double duty of protecting the curing resin from unwanted things like dust, cat hair, human hair, or anything else that might wander by and drop in.
My ‘hot box’ is made from a pair of cheap letter trays sitting on an inverted low-profile aluminum pan. Then, I place the trays on an electric heating pad (that has an automatic shut-off) and cover them with an inverted clear plastic storage box. I like the clear bin so I can see into the box, but I have seen hot boxes made with cardboard.
Tip 4: Warm up your resin mold.
When casting resin in cold weather, warm up the mold before pouring the resin using a heat tool. Just don’t get them too hot. If you overheat resin molds they can warp and distort. So, just enough heat so the mold is not cold.
After pouring the resin, using the heat tool not only helps to pop bubbles that might form but also helps to warm the resin and start the curing process.
After pouring the resin, I carefully remove the plastic bin without tipping it (to keep the trapped air trapped) and set it aside. Next, I put the freshly poured mold on the rack. If I am only inserting one mold, I put it on the bottom shelf, which is the warmest in my “hot box” because it’s the closest to the heating pad. Then, I replace the bin over everything.
Since the heating pad has an automatic shut-off, I check it several times during curing to ensure it’s still generating heat and hasn’t turned off.
Enjoy your cured resin charms!
When the resin is cured, remove it from the hot box and do the usual stuff to finish it.
The super clear resin cures to a demoldable stage in about 6 hours. That’s one of the big reasons I like using this casting resin in cold weather. This quicker cure time for an epoxy resin makes it great for a single-day project. If you take it out of the mold at 6 hours, when you first take it out of the mold, it will still be a little pliable but completely non-sticky. You can sand and paint or do other finishing effects immediately. The resin will continue to harden and should be fully hard after another 6-12 hours.
When I demolded the resin charms, the beaker was too thin right by the top. I didn’t want the item to get too bulky, and the bottle part was more recessed, so I didn’t pour enough into that cavity. The first time using a mold, you discover things like that. Next time I’ll be able to gauge the depth of that cavity better. Everything else turned out great.
I added a bit of paint and some bails to the skulls and eye to make resin pendants. I glued the eyes back to back with the bail between them to make a 2-sided pendant. I’m unsure what to do with the worms other than just leaving them on the counter as decoration.
I made a decorative tag with the vials and beaker. I added a bit of paint to the vials.
Are you having more challenges beyond resin casting in cold weather?
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Originally written by Kate Ledum
Unpublished Blog Posts of Resin Obsession, LLC © 2023 Resin Obsession, LLC