What Is The Best Epoxy Resin Mixing Temperature?

epoxy mixing temperature
TL;DR Your epoxy resin mixing temperature is essential for ensuring your resin cures. Your resin AND working area need to be at the right temperature. Otherwise, your resin may not cure or may cure sticky and full of bubbles.

Yes, epoxy resin mixing temperature matters.

Two-part resin kits have a bottle of resin and a bottle of catalyst (also called hardener). They don’t do much by themselves, but a chemical reaction occurs when you mix them together. This reaction produces heat, which turns the liquid into a solid. If your mix or work area is too cold, the mixture will lose heat too quickly. There might not be enough heat for the resin to cure. Or it may cure soft. Or with cloudy streaks.

⭐️ BONUS: Learn more about what is resin made of and what you can do with it.

So how do you make sure you are mixing your epoxy resin and hardener at the ideal temperature?

warming bottles of epoxy resin in a hot water bath

Warm your resin and hardener bottles.

Placing your resin and hardener bottles in a hot water bath for 5 to 10 minutes will warm the contents. Place the bottles inside a plastic bag before placing them in the water bath. You don’t want to destroy the labels and lose your directions and safety precautions.

💡 Pro tip: Before pouring, make sure your bottles are dry, as you don’t want to contaminate your resin with water. Resin hates water and may not cure.

If heat is great, why not warm the resin up in boiling water and get it REALLY hot before using it?

Yeah. Just like eating the entire family-size bag of sour cream and onion potato chips, there is too much of a good thing. If your resin is hot when you start, your pot time (amount of time to work with the resin before it starts to cure) will be significantly shortened. Your resin may begin to cure before you have it cast.

I know because it’s happened to me.

⭐️ BONUS: What happens when your epoxy overheats.

Make sure your room is at the right temperature.

Room temperature also impacts how well your epoxy cures. Your room should be in the low 70s F range. Below that, your resin may not cure. Above that, your resin may dry too quickly.

So what do you do if your resin crafting room is a large area that is hard to heat or cool?

Here are a few ideas:

*Close off a smaller area, like a closet or bathroom, and heat/cool that area with a space heater or air conditioner.

*Create a ‘hot box’ for your resin projects.

You also need to make sure your resin work area stays at this temperature the entire time the resin is curing. Otherwise, it may cure soft or take longer than expected to cure.

⭐️ BONUS: Get more cold-weather resin casting tips.

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33 thoughts on “What Is The Best Epoxy Resin Mixing Temperature?

  1. I have bought the easy cast resin in the 64 fluid oz jugs. Within a month the hardener turns a dark yellowish color. Is it going bad or am I doing something wrong ?

    1. All hardeners will turn yellow with time. Unfortunately, it sounds like the kit was old when you bought it. I would expect your castings would continue to cure as normal, but they will have more of an amber tint.

  2. How can I keep deep resin casts from cracking or feathering….I have tried layering…but hard to get each layer at right time so doesn’t show a line or anything….any help.
    Am casting rattlesnake head in clear solid ball…about 2 and 1/2 inches wide and tall.

  3. I learned my lesson with my resin pot time being shortened due to my room being too warm and me heating my resin as well. I mixed a batch and set my timer. Before I could get my resin separated into smaller cups with colorants, the resin had already begun to start getting sticky. I have since been keeping my air conditioning on and not warming my resin near as warm as those first tries. Resin is so much fun and I really have enjoyed the break from my wire wrapping too. I will no longer have to throw away resin due to a shortened pot time. #liveandlearn

    1. Thank you! I’m new at this and I had the same thing happen and almost ruined paintings because it cured to fast! Mystery solved!

  4. Can u pour resin to make coasters if it is rainy weather. I keep my room temp. On a constant 70-72 degrees. The humidity stays between 40 and 45 . If it is mixed correctly should it be ok to pour on a rainy day or continuous rainy days?

    1. As long as it’s a resin that isn’t bothered by moisture (some polyurethanes don’t handle humidity well), you can pour resin on rainy days.

  5. I would like to make a small resin table, what kind of things can I use? If I use wood do I just painters tape the pieces?

    1. Hi Bill, I’m not sure I understand your question. You want to make a resin table or you want to apply resin to a table?

  6. After pouring two levels of your deep pour resin on a river table project can I top off the last half inch with Art Work resin?

    1. Hi Norma, great question! Artwork resins are only meant to be poured at depths of an eighth inch or less. At depths greater than that, all the bubbles may not release before it starts to cure.

  7. I have a large indented circle in the middle of the resin pour that is dry …can I just pour the circle level to the rest or do I have to pour the whole thing again

    1. Hi Barbara, I’m afraid resin doesn’t work well as a ‘spackle’. You will need to recoat the entire surface, otherwise, you will see a line.

  8. Can I put cured resin in a 230 degree oven for 30 minutes? I’m using polymer clay in resin layers, and need to bake between layers.
    Or can raw polymer clay be imbeded in resin?

    1. Hi Donna, I’m afraid you can’t put cured resin in the oven. You will need to do all your polymer clay work first, then apply resin.

  9. I’m using pro marine for a tumbler and no matter what I do I get fish eyes
    – it’s clear and mixed well , room does dip in temp . Can I sand and put another layer on and does cold cause fish eyes or just keep it from curing ?

  10. I’m trying to do waves on a sea scape in my garage in the UK. When I put the white on and “push it” with the heat gun it looks great, but after it has been left to cure it just molds into a cloudy mess without any clear “cells” or waves. How do I prevent this from happening. Is my garage too cold?

  11. You still didn’t answer my question. At what temperature should my house be to mix and properly cure??

    1. Hi Kathleen, it sounds didn’t have a chance to read that part of the article. Ideally, the temperature of the room that you’re doing resin crafts in should be about 70 to 75 degrees F.

  12. I have tried so many different things to make my resin so it dries clear and nothing seems to work. I always have swirly, cloud like anomalies throughout the resin. I have tried heating the resin, mixing it slower for longer, doing 2 layers of resin and I can’t seem to get rid of the swirls. Please help!!!

  13. I forgot to warm up my bottles before using them 😂 now I guess I get to see what happens first hand when I demold them tomorrow after they supposedly soft cure! Oops 😬

  14. We are having a really hot summer here in South Africa. I am using epoxy resin with fibreglass to cover a wood strip canoe. Can I work with epoxy at 35°C? Should I start early when it’s cooler and leave the resin to dry as the day heats up? Or should I work late and leave it to dry as temperatures drop to about 25°C?

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