Does epoxy melt in the sun?

You’re looking to build a table for a summer barbecue. You have the legs cut and sanded, you’ve stained all the pieces, and you’re ready to put it all together.

Your thoughts turn to epoxy—it makes such beautiful, durable tables! But can epoxy withstand the heat of summer?

Can epoxy stand up to the sun? In this article, we’ll tell you whether or not epoxy can handle the heat of direct sunlight. We’ll also discuss your options if your plans for epoxy just won’t work out in the end.

What happens to epoxy resin in the sun?

In case you’re wondering, yes, sunlight can have a big effect on epoxy resin. And no, we don’t recommend that you leave your epoxy resin out for prolonged periods of time as it will degrade and decompose.

But if you find yourself in the same predicament of needing to repair or replace an item that was damaged by UV rays (the sun), then this comes in handy.

Does epoxy melt in heat?

So, you’re wondering whether epoxy will melt in the heat. We hear this question more and more frequently as our summers get hotter and hotter!

Unfortunately, the answer is no. It won’t melt, because epoxy doesn’t begin to melt until it reaches 150 degrees Fahrenheit (65.5 degrees Celsius).

However, it does start to cure between room temperature and 80 degrees Fahrenheit (26.6 degrees Celsius).

This means that if you are going to be transporting an epoxy project and the weather is warm, make sure that it is in a well-ventilated area with adequate airflow so that your epoxy remains uncured as long as possible.

Can resin be kept in sunlight?

If you’re working with epoxy or polyester resin, it’s important to make sure it doesn’t heat up too much. This could cause the resin to yellow, weaken, and become less effective.

In general: don’t leave your resin in direct sunlight. If you do, the resin may yellow over time and weaken. However, if you need to keep it out of the sun for a little while – say on the dashboard of your car – then it’ll be okay for a few hours.

Can epoxy dry in the sun?

The answer is yes, epoxy resin can cure the sun. The problem occurs when the epoxy overheats. If it gets too hot, the heat will cause a chemical reaction that can change the look of your piece and potentially ruin it. [LINK]

If you’re looking to create an epoxy resin project that’s going to be exposed to sunlight, there are a few things you should know:

  • Epoxy resin hardens best when its temperature is between 70-85 degrees Fahrenheit (21-29 Celsius). Sunlight can raise the temperature of your piece above this threshold, so it’s important to keep an eye on how warm your resin is getting. You may want to use fans or air conditioning to keep things cool enough for curing.
  • If you notice bubbles forming in your resin, it could indicate that your project has gotten too warm and some chemical reactions have already taken place. This doesn’t mean that this is the end of your project! If you can deal with any opacity issues by adding another coat of pigment on top after curing (if applicable), then you will probably be okay.

Why does my resin bend in the sun?

If you’re new to resin crafting, it’s important to understand how epoxy resin and sunlight interact. It’s also helpful to understand how epoxy resin reacts to heat and cold–both of which can happen when you leave your project in the sun for too long.

Epoxy is a polymerizable compound that eventually hardens into a solid, plastic-like material. The process through which this happens is called polymerization.

The speed of polymerization depends on the temperature of both the component parts of the epoxy, as well as the surrounding environment. The warmer everything is, the faster polymerization will occur.

The rate at which epoxy heats up in direct sunlight depends on 1) what type of epoxy you are using (i.e., crystal clear or colored) and 2) whether your piece has any dark or black elements on or in it (for example, dark pigment powders).

In general, crystal clear epoxies will heat up more quickly than colored epoxies because they have less opacity blocking out UV rays from reaching the liquid resin underneath.

If your project contains a lot of dark colors (like black), then those darker areas will absorb heat even more quickly and cause even greater temperature differences within your piece.

If this is happening with your piece but you want it to be level instead of wavy or curved, then we recommend readjusting your mold so that gravity flattens out any uneven sides or edges prior to curing.

Will epoxy crack in cold weather?

Yes. Epoxy can crack if exposed to temperatures below 50°F, which is why you don’t see many people using epoxy resin in ice sculptures or for other applications where the temperature will be very cold for a lengthy period of time.

Extreme cold can cause the resin to become brittle, and cracks occur when the brittle resin is exposed to heat or when it’s stressed by being placed under weight or flexed.

Even if you apply epoxy resin in hot weather, high ambient temperatures can cause cracking as the epoxy cools and shrinks.

Epoxies are susceptible to stress cracking slowly over time with continued exposure to heat and sunlight as well.

How do you make epoxy resin heat resistant?

There are a few ways you can try to achieve that, depending on what product you’re using.

  • Use a UV-resistant resin. Some resins made for outdoor applications, like casting tables and countertops, are specifically formulated to be more resistant to UV degradation than other kinds of epoxy resin. These might last longer in the sun without yellowing or producing VOCs.
  • Use a UV-resistant additive. In addition to using a UV-resistant resin, you could try adding a special additive to your epoxy that gives it added protection from the sun’s rays. This is common in industries like boating where epoxy resins are often exposed to sunlight for long periods of time as they cure while out at sea.
  • Use a UV-resistant pigment or colorant: If you want your cured piece of epoxy resin to be transparent, you’ll need something else to give it sun protection—like a special colorant designed for this purpose! The most popular way people make DIY epoxy products resist the sun is by coloring them with pigments that have been treated so they won’t break down when exposed directly to ultraviolet light (UV).

What happens if epoxy gets too hot?

When epoxy is exposed to heat, it can split, bubble, warp, and crack. It also becomes brittle and softens. The higher the temperature, the worse any of these problems will be. Your epoxy could become so damaged that you have to tear it out and start over!

If your epoxy hasn’t yet cured, the best thing you can do is get it out of the heat as quickly as possible. Even after it has cured, though, if temperatures are rising beyond 100ºF (38ºC), there are a few steps you can take that might save your project from cracking or splitting later on.


It’s important to remember that epoxy, like most substances, is sensitive to both high and low temperatures. If exposed to too much heat, the resin can start to melt or warp. Too much cold can cause the resin to crack.

Of course, your results will vary based on which type of epoxy you use. Some formulations are more heat resistant than others, but if you’re going to be doing any work outside in the sun, it’s a good idea to have all the information before getting started. You don’t want all your hard work expanding or contracting!

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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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