Can you cure resin in sunlight?

First off, let’s be clear: if you’re looking to cure resin in the sun, this article is not for you. You can’t (at least on a practical level). But maybe you’re asking this question because you’re an artist or crafter who works with resin, and as a matter of course, your project has been accidentally left out in the sun.

Or maybe your project was supposed to be cured by the UV rays of the sun but didn’t turn out quite right.

Either way, it’s best that we start by covering some basics about curing resin so that when we get into what’s actually going on with sunlight and resin, all these terms will make sense to you.

Can you cure resin in sunlight?

Can you cure resin in sunlight

Can you cure resin in sunlight? Yes, you can. But before we get into the details of what that process looks like, let’s look at a few potential issues with doing so:

The sun can cause resin to yellow or even burn. The sun is a natural source of UV light. Most epoxy resins react poorly to UV light during the curing process and will turn yellow over time.

Curing in direct sunlight could cause your piece to discolor much faster than normal.

Epoxy resin will take longer to dry in sunlight. Heat helps accelerate the curing process for epoxy resin, but not all heat is created equal.

Sunlight from the sun is more intense than artificial sources of heat (like a heating pad), so it will take longer to reach a safe temperature for your pieces to cure properly when using the sun as a heat source.

If you do choose this method make sure you watch your project closely and adjust the amount of time spent in direct sunlight accordingly; if left unattended under direct sunlight for too long, your piece could potentially burn!

It’s harder to control the curing process when using sunlight as opposed to an artificial source of heat (such as a heater).

When curing with an artificial source of heat, there are many ways (thermometers, timers, etc) that allow us to control temperature levels and track how long our projects have been exposed – which means less guesswork on our part!

It’s also easier because we know roughly how hot or cold our workspace is outside of any additional appliances being used which makes calculating different factors much easier than if one were trying their hand at curing under direct sunlight where there are no tools available that would allow us greater insight into these conditions…

What happens to resin in the sun?

Most people are aware that resin should be kept in a cool, dark place and only exposed to UV light when curing. If it’s not cured correctly, the resin will remain sticky or soft.

What is less whispered about, however, is what happens if resin is exposed to sunlight. Essentially, it will cure very quickly!

There are obviously pros and cons to this process. The sun’s rays can shorten your work time and give you a nice tan or burn, but if you’re working with many layers of resin this could turn problematic.

Can you leave resin in the sun?

Can you leave resin in the sun

There are two main reasons why you should never leave your resin in the sun.

When resin is exposed to sunlight, it heats up! This heat can speed up the curing time of your resin. This could potentially ruin your project because you will not have enough time to mix and pour your resin properly. It also means that any objects you put in your resin might float to the top since they are heavier than resin.

  • Reason 2: High temperature can cause discoloration or yellowing effect

High temperatures also encourage UV rays which can cause discoloration on cured and uncured resins alike! If you are working with clear or colored resins, this could potentially ruin the appearance of your work.

If possible, always try and cure your resins indoors where they are protected from direct sunlight and other sources of heat such as ovens, radiators, etc

How long does resin last in the sun?

How long does resin last in the sun

Well, you can cure resin in the sun, but there are a few drawbacks. The ever-important curing process will take longer with sunlight than it would indoors with a more controlled light source, and you’ll need to make sure your resin piece doesn’t get too hot and melt!

Sure, some people have had success leaving their resin out in the sun to cure, but that’s not what I recommend. A well-ventilated area (like a garage or covered porch) is probably the best place to let your resin pieces cure if you’re looking at doing it outdoors.

It’s also important to remember that even though you might be eager to see how your piece turns out as soon as possible, you should always wait at least 24 hours before moving on with any of your projects.

Once your project has cured for 24 hours (or whatever length of time is recommended on the label), then it’ll be safe for sanding and painting!

Can epoxy dry in the sun?

Can epoxy dry in the sun

This is something that many people have asked. Can you cure epoxy in sunlight? The answer, unfortunately, is no.

Epoxy resin needs to be exposed to UV light to cure. The UV light starts the chemical reaction with the epoxy and hardener, which will lead through the exothermic process where resin cures. Sunlight contains a lot of different wavelengths and some of them will help cure your resin.

However, it’s not enough. You also need a UV-A lamp for curing your resin (as well as temperature control), so that you can be sure that your project turns out just as you want it to!

Can UV resin dry in sun?

Can UV resin dry in sun?

Yes, UV resin will cure in sunlight. However, how quickly the resin cures will depend on the strength of the sun and the formulation of your UV resin.

For example, if you are curing your UV resin in a commercially sold UV curing box or under an LED lamp, chances are your resin is a very high-quality product (as it needs to be for commercial use) so it may dry very quickly in sunlight.

In contrast, if you are using a lower quality brand of UV resin, its properties may have been altered to reduce costs which would slow down its rate of curing.

Regardless of which type you use, be sure that you do not cure any type of UV resin indoors as chemical fumes can build up over time and cause health problems if inhaled repeatedly.

Will resin last outside?

Will resin last outside


Yes, the sun’s UV rays can yellow epoxy resin, but it depends on how much resin you’re working with, and what type of resin it is.

The smaller the piece or the thinner the layer of epoxy resin, the less time it will take to yellow. You may have heard that you should use a UV protectant spray on your project to protect against this discoloration.

While this statement is true in general, there are some important distinctions to make between products that claim they are “UV stable” and those that say they are “UV resistant.”

Does resin last in heat?

Does resin last in heat

  • Be sure to store your resin in a cool, dry place away from direct sunlight when you’re not using it.
  • If your resin has been exposed to heat, slightly cloudy areas may appear on the cured surface that can be easily polished off.
  • If it’s too hot or too humid for you to be comfortable working outdoors, it’s probably best to postpone the project! Do keep in mind that if you choose to work outside during the day, you will need to protect your pieces from direct sunlight once they reach their final cure time of 12-24 hours. For example, if you live in Miami and choose to work on a day where it’s 94 degrees outside, remember that anything left out overnight will feel like an oven at 10 am the next morning! So make sure all of your items are protected from prolonged UV exposure by bringing them inside or covering them up with a towel once they reach full cure.


So there you have it, folks. If you’re an avid resin user, you can now add UV protection to your list of concerns—but the good news is that there are a variety of ways to make sure that your creations can stand up to the sun without fading or discoloring.

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Martin Flood

Martin Flood has been working in the construction industry for over 20 years as a general contractor with expertise in remodeling projects that are large or small. He has furthered his career by specializing in epoxy resin flooring, providing excellent service to both commercial and residential clients. Martin’s experience enables him to offer professional advice on how to choose the right type of project based on your needs and budget.

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