Cold weather resin tips – casting resin in cold temperatures

Casting resin in cold temperaturesOne of the things I love about living in Florida is that our winters tend to be quite reasonable.  That doesn’t mean we don’t have any cold days, but I know that when the cold ones are here, warm ones are only a couple of days away.  It also means that I generally don’t have to worry about casting my resin in those cold temperatures.  I know many of you aren’t so lucky, so here are a few of my cold weather resin casting tips.

Before we get into that, here are some basic resin principles you need to know:

Resin and the hardener (or catalyst) are two inert substances by themselves.  Once they are mixed, a chemical reaction occurs that produces HEAT.  This is what causes your resin to cure (or harden).  Ideally, for this reaction to occur, your room temperature needs to be 70 to 75 degrees F.  That’s not so difficult to achieve during the summer, but during the winter, it can be tough.  Here are some things you can do when you are cold-weather resin casting:

Here are some cold weather resin tips to make sure your resin cures hard and clear:

resin hot box

1.  Create a resin ‘hot box’.  Take a large cardboard box, put in a gooseneck lamp with an incandescent bulb.  Turn on the lamp while your resin projects are curing.  The incandescent bulb will create a little bit of heat and the cardboard box will keep the heat inside.  Be sure your projects are covered, as those bulbs also tend to attract dust.   If you’re lucky enough, you could even use a metal cabinet in your garage.  It would even have shelves for your projects!

This article shows how to use a hand-warmer to create heat for resin curing.

2.  Cast your resin in a smaller room and use a space heater.  Make something like a bathroom or a walk-in closet your resin casting room during the winter.  Turn on a small space heater while you are casting your resin.  The heater should allow you to bring the small space up to the low 70’s without turning on the full heat to your house and breaking the bank on your utility bill.

**On both of the points above, please don’t leave anything unattended.

3.  Make sure your resin is warm before you use it.  If your resin bottles feel cold to the touch, put them in a warm water bath for 5 minutes at a time before using them.  Make sure to dry your bottles well before using them.  You don’t want that water to drip into your resin!

4.  You may have to consider a different resin.  Safety is very important, and I love hearing that many of you will have an open window if necessary while casting.  For me, I don’t find any problems casting epoxy resin indoors.  Even if it is a warm room (while the rest of the house is cold), having a small fan on simply circulating the air is enough for me to work with the resin.  Something like polyester resin, though, is a different story.  I NEVER cast that resin inside my house because the smell is heinous.  If I need to cast polyester, I can wait a few days until the outside temperature has gotten back above 70 F.  For those of you in a cold climate, you may have to wait until summer arrives again and use something different in the meantime.

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5.  Warm your mold before pouring the resin.  Before pouring your warm resin in your warm room into your cold mold, run a heat gun over the mold first.  Warning — plastic molds can warp or melt if the heat gun is left on them too long.

6.  Give yourself more time.  Just because your room is 67 degrees today and not 70 degrees, does it mean your resin won’t cure?  No, of course not, but it will cure slower.  Know that it’s going to take extra hours for your resin to cure if the room temperature is a little less than ideal.

What other changes do you make when it comes to cold temperature resin casting?

Confused about how to use resin to craft something beautiful?  Tried resin only to find you have sticky, bubble-filled results?  It’s not your fault!  There is so much out there to know about creating with resin — how can you possibly know it all?  That’s why I wrote the book Resin Fundamentals.  I’ve condensed my fourteen years of resin experience into a clear path that resin beginners need to take to craft something that has people saying, ‘Wow, that is incredible!’  Buy your copy now and get an email with your download instructions in only a couple of minutes!

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33 thoughts on “Cold weather resin tips – casting resin in cold temperatures

  1. Thank you for the tips! I hadn’t thought about a ‘hot box’.

    For curing shelves, I bought some really cheap stacking horizontal letter/paper trays at Staples. The clearance between trays is enough for my smaller molds and a low cover. Since the top tray is open on top, I put larger stuff there or even end up stacking mold-cover-mold-cover. I put parchment paper or wax paper down on the tray before putting a resin filled mold on it. If there is an over spill, it won’t stick to the tray.

    Link just for the visual of what I mean by letter tray: I think mine were cheaper yet ’cause I don’t care what they look like.

  2. Thanks for the hotbox idea! It took my last resin project a week to cure as we keep the house under 70F in the winter.

  3. Even here in Atlanta we have plenty of cold days (like the rest of this week!). In cold weather, I first try to do my resin casting upstairs, as it remains warmer there (heat rises…), as opposed to downstairs, even though downstairs is more convenient. Sometimes I will just set up a small, square folding “card table” on which to do the project in a corner of the living room. Then I also keep a small, adjustable desk lamp pointed over the project while it cures. And I keep the project covered using the most appropriate size (based on the number of pieces in my run) of clear plastic storage bin/container (slightly raised up on at least one side to allow for air flow but to limit dust and to help concentrate the heat from the lamp’s light bulb for warmth).

  4. Hi I was wondering do you think I could work on the resin in my basement then give it a few hours to set and then bring it upstairs? If you think that would be ok about how long would you wait.
    Thank you

    1. Hi, yeah I have used UV lamps for the UV resins and tried underwater curing. However, I obtained curling. Is there anyway to get rid of the curling of the edges? do you know what is the curing time underwater?

      1. I haven’t used UV resin much and can’t make a recommendation. I would suggest asking the manufacturer for help.

  5. Hello,
    Just wanted to share my method of dealing with cold temperatures!
    My room is absolutely freezing! Not ideal for resin.
    I was really confused as made two pieces, one cured fine the other was still taccy [I always take great care to mix and never encountered non curing or taccy resin before] . I then realized the piece didn’t work as I was including a large metal disk in the resin and the metal itself was cold as ice.
    My solution? As well as warming the resin before use, I didn’t have a suitable lamp to make a warm box so I used a small hot water bottle I had.
    I placed it inside a wooden art box suitcase type thing, I’m sure just under a regular cardboard box would be fine too and placed my resin pieces on top.
    It worked like a charm! Perfect for my metal pieces as maintains a warm temp in the inclusion and stops them going ice cold again.
    Thanks everyone for sharing you advice and I hope this might be of help to someone too!

  6. I prewarm my resin in a water bath, and my molds in a food dehydrator. Then I let them cure for 12-24 hours in the garage (This is TX, so it’s 60 in there overnight). Then I demold and place the pieces in the food dehydrator. I run that for a few hours, let them cool down and I have rock-hard cured resin.

  7. Thanks for the tips!
    I have only one question: I have to warm the resin AND the hardener (or catalyst)???

  8. Thank you for this great information! Fall is definitely arriving here in Kentucky, and it’s only 66 inside the house. I’m just going to wait till around lunchtime when it warms up a little bit more. Thanks again!

  9. I live in England so it’s very cold here, we usually have the heating on would it help to place my resin in its mould son a radiator?

  10. ? Turned my shed to a studio. Come winter and cold i have a small heater. But u can see the hot coils. If u tip it it cuts off. Hubby concerned about coils n toxic resin. Is this dangerous. Ty

    1. I’m not sure I understand your question. Are you worried about getting the resin too warm?

  11. I think they were somehow concerned about the red heating coils in the heater and the fumes from toxic resin, that the heater would somehow ‘ignite’ either the fumes or perhaps the resin itself like a flammable liquid like gasoline.
    At least that is my estimated guess to what the above commenter was asking about dangerous.

  12. I’m VERY new and VERY inexperienced with resin and just started. I’ve only done it twice (first time was MAJOR failure, 2nd time was just last night). Here’s my big question. I’ve been reading through all the great info here and I see that you can cover the resin projects with boxes and lids. My big problem/question is can resin projects be placed in a closed drawer or a cabinet with doors shut as it cures??? I rescue cats and have started resin as a way to hopefully bring in some funds for the rescue but that means I HAVE CATS lol Some are sweet but then some do everything possible to get into trouble. I have a small old house which is very cold right now. My tiny bathroom is not working out well with balancing projects on the tiny (only) shelf I have in there with the heat vent open. I’m kind of at a loss right now as to how to keep projects safe, both for the project’s safety and the kittens. 🙁

    1. Hi Laura, I understand it can be stressful trying to keep your projects safe while they cure. Yes, you can put them in a drawer while they cure. You could even include a heating pad to bring up the temperature.

      1. 2nd time turned out AWESOME! I read many many articles here and did the following: put the bottles in XL bag then into warm water bath about 10 mins before starting. While mixing slowly, I had a heat gun on low blowing toward cup. Turned out crystal clear! PROBLEM – finding a “safe zone” to cure. 🙁 My idea of having piece in bathroom was a good one, but they got bumped and therefore pieces were “uneven”, almost like they were tipped so one side is higher. Also even tho I had cardboard covering the top, there were still a few friendly cat hairs that snuck inside. I’ve read so many different things, so I’m nervous/unclear about how exactly they can be stored as they cure. They can be placed in a drawer or cabinet with doors shut. I actually have a dresser with shelves that I may just use for resin to cure. I can put the projects on the shelves and then place a heating pad somewhere on one of the shelves? Does it need to be a certain distance away from the projects? or can it be next to? I’ll bungie cord the door shut so they can’t get to anything. This will be ok? I love the tutorial on the cheese board and would like to try it! 🙂 THANK YOU SO MUCH!

  13. Thanks so much for this article. I’m very new to resin and I have questions about the curing process. I plan on mixing and casting the resin outdoors since I have a small outdoor space but I’m having trouble figuring out where to leave it while it’s curing. Resin is still toxic while its curing and I’m trying to avoid bringing it indoors while it cures for that reason. However, I can’t leave it outside to cure even if I cover it because it gets to about 50 degrees at night where I live. I have a cat and I don’t want to expose her (or myself) to the fumes at all by bringing it indoors. I live in a small apartment and I have an extra closet where I can leave it to cure indoors. I’m wondering if I can leave the resin inside of a cardboard box or storage container, in the closet, while it’s curing? Will I still be breathing in the fumes? Am I being too cautious about this?

    1. Hi Lindsay, I appreciate that you are taking resin safety seriously. I wish everyone did!

      Firstly, you should be using a resin that conforms to ASTM D-4236. This is a resin that has been reviewed by a toxicologist and deemed safe for use for art purposes in any location. All of the resins sold on Resin Obsession have this certification. You can find them here:

      For more details, you can consult the safety data sheet for the resin you are using. It will make detailed recommendations as to how to use the resin safely indoors. Not all resins have the ASTM certification nor will the manufacturer provide safety data sheets. This is unacceptable in my opinion and I would never use a product like that.

  14. hi! ok a few questions. i did my first poly resin cast indoors as its 50 degrees here and i’ve had the space well ventilated but the smell is taking over… i read above that you can store the cast while it’s curing, so i assume that i can put it in a box (probably will try a tupperware container) and let it sit for at least 24 hours before taking it back out of the storage container… does that sound ok to do? i pretty much just want to put the cast somewhere so the smell will stay contained instead of spreading throughout the house. next, if i were to use a heating pad, i guess i don’t understand how to do this? do i put my storage box (not a tupperware container in this case) on top of the heating pad and use it on low heat as to not overheat the cast? i need more, transparent information as i am new to this! any input would be greatly appreciated. thank you!!!

  15. You could go down to your Sporting Goods store and get some hand warmers Walmart carries them and they get warm enough to cure your resin

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