At some point, as you are mixing epoxy, you may find yourself asking, ‘why is my resin thick?’ It can be a little concerning to work with resin and wonder if you’ve done something wrong. Let me assure you that it isn’t that unusual and may not even be a problem. So here are a few reasons why your resin can be thick.
It’s a doming resin.
Doming resins mix thick, which allows them to coat tumblers, countertops, epoxy art, and more. The thick viscosity of doming resin is what enables it to coat surfaces evenly and without resin holes or fish eyes. For this reason though, it isn’t is the best choice resin for molds and should not be poured more than 1/8 inch thick. When poured in layers deeper than that, it’s hard for bubbles to escape before the resin begins curing.
If you have stored your resin somewhere that isn’t climate controlled (like a garage or car trunk), and the outside temperature is cold, your resin will be cold too. Chilly resin is thicker and much more challenging to mix without creating a lot of bubbles.
It’s beginning to cure.
The working time of resin (also known as the pot time) is the amount of time you have to use your resin once the two parts (resin and hardener) are mixed together. The mixture gradually thickens as you get closer to the end of the resin’s pot time.
Now that you have answers to the question, ‘why is my resin thick,’ how do you fix it?
Option 1: Use a casting resin
If you’re using resin molds, you want to use a resin formula specially designed for molds, also known as casting resins. They mix in a thinner consistency, making it easier to blend without introducing bubbles. Plus, when you do get bubbles (there will always be a few to take care of), it’s easier for them to rise to the surface, where you can pop them with a heat gun.
BONUS: Learn more about the differences between casting resins and doming resins.
Option 2: Warm your resin kit
You can thin the consistency of your resin kit liquids by warming them in a hot water bath for five to ten minutes before use. Imagine the difference between cold syrup and warm syrup. That’s what happens here. The resin and hardener still work the same, but blend easier and with fewer bubbles.
BONUS: Learn how to warm up resin in a water bath in this article about cold weather resin casting.
Option 3: Use a resin with a longer working time
If you can’t use all of your resin before it starts to thicken, you might want to use one with a longer working time. Each resin formula has a specific amount of time you can work with a resin once it’s mixed before it starts to thicken. This time, also known as pot time, varies between resin kits. So look for one that gives you longer to work with it.
BONUS: Get working time information (and more!) for my favorite resins in our resin buying guide.
What about using liquids to make resin thinner?
While you can use solvents like acetone and alcohol to thin out resin, they aren’t without risk. Besides being flammable, they can keep your resin from curing if you use too much.
BONUS: I will thin out a single resin color when trying to create lacing in resin paintings. You can see what I do in this article on how to make resin cells.
If you have other questions besides why is my resin thick, I want to help!
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