Yellowing is a natural part of epoxy’s lifecycle. It does not have to be this way, however. Let’s first look at what causes yellowing and then go into what products can prevent it from happening.
Epoxy is a substance that contains both an epoxide group and two hydroxyl groups. It is created by reacting a resin with a hardener or catalyst, giving the epoxy its strength and stability.
Over time, UV light can cause the double bonds between carbon atoms to break down, creating free radicals that attach to oxygen molecules in the air.
These free radicals create peroxides that alter the chemical structure of the epoxy, causing it to yellow. No matter how many antioxidants are added to your product, it will still eventually yellow due partly to
The rate of yellowing depends on several factors including:
- UV exposure
- Humidity level during curing
How do you keep epoxy from turning yellow?
At the end of this guide, you’ll learn how to keep epoxy from turning yellow, what products work best for a non-yellowing resin, and how to fix epoxy that has already turned yellow.
You’ll also discover how to avoid having your project ruined by using a practical approach and the right product.
Table of Contents
Does all epoxy yellow?
- The short answer is: no, not all epoxy yellows. Sunlight and UV rays are the main cause of yellowing; heat and humidity can also accelerate the process. But there are ways to prevent this from happening!
- When sunlight hits the epoxy surface, UV rays break down molecules in the resin. In some cases, it may take several years for this to happen, but as a result of exposure to UV light or other environmental factors, epoxies can develop cloudiness or an amber cast. A resin that contains a UV stabilizer will provide better protection against yellowing than one without.
- Another way to avoid yellowing is with a low viscosity resin. Epoxy resins with high viscosities (thickness) trap air bubbles more easily during application and make it more likely that they’ll be visible in your finished product. As these bubbles cure over time, they oxidize and turn into tiny pockets of air that look cloudy when you hold up your piece against the light—the opposite of what you want!
Does all epoxy resin yellow over time?
The good news is, not all epoxy will yellow. It’ll be very difficult to find a resin that’s completely immune to the effects of UV light and completely clear forever, but some resins are more resistant than others.
A few clever companies have found ways around this problem by adding other ingredients to their resin formulas to help filter out the UV rays and keep your pieces clear for months. These options are usually called “Art Resins” or “Non-yellowing Resin”.
They can get pricey though; most art resins cost over $100 USD per gallon! Luckily, there are a few other things you can do besides using an Art Resin to ensure that your piece stays crystal clear.
Try keeping it away from direct sunlight (or at least indoors) as much as possible. If you’re making a bar top or countertop that will be exposed to direct sunlight, I recommend using one of the non-yellowing epoxies mentioned above.
You may also want to try coating your final piece with a UV protectant spray! The exact same thing that keeps our skin from tanning too fast works wonders on resin as well, keeping all those little photons from altering the color in any way!
What is the clearest epoxy resin?
What is the clearest epoxy that doesn’t yellow?
We don’t wish you any bad luck, but sooner or later you will likely experience yellowing of your resin project. Resin is fun and exciting, but it has its drawbacks.
Depending on how and where the resin is used, it can change color if exposed to UV light for too long. It’s not a big deal because there are ways around it. The trick is to use the right resin in the right place to avoid unsightly yellowing.
So what about clear epoxy that won’t turn yellow? In fact, most castable resins can be made clear or close to clear.
Castable resins are those that harden when exposed to air after being poured into a mold. You may have seen them used for making jewelry or other projects like art pieces and sculptures. When hardened properly without exposure to UV light, these resins will remain transparent!
The problem comes from casting in a mold with a lid or glass top that allows sunlight through while drying; the sun’s rays cause chemical changes within the resin causing it to become cloudy with age–which means we need something more than just regular old epoxy resin.
Luckily there are some options such as polyurethane based resins which won’t yellow over time because they contain no UV inhibitors whatsoever (that means they’re safe under virtually any conditions).
However, there also exists another option that many people don’t know about: using an epoxy casting compound mixed together by hand at home instead of buying ready-made products off store shelves!
This technique allows us greater control over our creations because we can add whatever additives we want into our mixtures including UV inhibitors so they do not discolor over time from exposure outside on sunny days!
Is there a polyurethane that doesn’t yellow?
I think you might be confused about the terminology here. Polyurethane is not a resin; it’s a type of plastic that can yellow, just like any other plastic.
Polyurethane is actually a type of plastics chemistry, which is to say that there are many different types of polyurethanes (the word “polyurethane” literally means “many urethanes”). Urethane refers to the chemical group called “urea,” so polyurethane literally means “many areas.”
A urea group consists of two carbon atoms and one nitrogen atom attached to each other. The resulting polymers have large molecular weights, making them good plastics for wood finishes and adhesives because they form rigid chains that bond well with substrates, in this case, wood.
Does Pro marine epoxy yellow?
The short answer to this question is yes, Pro Marine epoxy does yellow. It just does, so you can’t expect it not to. This is a common characteristic for most epoxies, though you might be able to find some that don’t.
It’s important to understand the difference between yellowing and discoloration when it comes to making your own resin artworks at home or elsewhere.
Yellowing occurs due to exposure to UV rays while discoloration is simply a result of changes in color/consistency over time.
Yellowing happens all the time with exposure so there isn’t much you can do about it; however, there are ways (such as using pigments) that might help prevent discoloration from occurring later down the line.
Does Famowood epoxy yellow?
Here’s what geniuses like you should know about Famowood epoxy: it does not yellow.
Famowood is a two-part epoxy that mixes easily and can be used on wood, metal, brick, concrete, and more. It self-levels for a super smooth finish, and with UV blockers in the formula, it won’t yellow as other epoxies do over time.
The color options are semi-transparent stains or clear – perfect for restoring antiques or creating works of art with light shining through them.
Can you use resin if it’s yellow?
If your resin has already yellowed, there is no way to reverse it. While yellowing can be caused by a number of factors, all of them boil down to a chemical reaction between the resin and another substance that causes discoloration.
For example, polyurethane resin will turn yellow when exposed to UV rays or fluorescent lighting. In this case, you’re dealing with photo discoloration.
The ultraviolet rays cause chemical reactions in the resin, breaking down its molecular chains and creating new ones that create the yellow color you’re seeing.
As it happens, ArtResin is formulated specifically to resist photo-discoloration. That’s why we can guarantee our product won’t yellow at all for up to 10 years! However, not all epoxy resins offer this protection against discoloration – even many ‘clear’ epoxies are not UV stable (and will therefore turn yellow).
That’s why it’s important to check what kind of epoxy you’re using…but even if you use an epoxy that turns out not to be completely resistant to UV light, your finished piece probably won’t turn completely brown overnight.
It might take years and years before it gets really noticeable — but nevertheless, we always recommend using a UV stable resin-like ArtResin if possible!
But what about non-photochemical discoloration? There are many other scenarios where your resin may end up turning yellow over time:
• Heat – heat sensitivity is another good reason for choosing ArtResin as its heat tolerance allows for curing in hot conditions without any distortion or warping! Our competition isn’t so lucky…prolonged exposure to high temperatures will cause many clear epoxies like Pro Marine Supplies Crystal Clear Epoxy Resin (which only withstands 70 degrees Fahrenheit) or West System Epoxy Resin (which only withstands 77 degrees Fahrenheit) or Easy Composites Clear Epoxy Resin (which only withstands 70 degrees
Choosing the right epoxy resin for your project means not having to worry about it yellowing in time. The epoxies we reviewed above will all keep their clear, beautiful shine over time.
If you’re still unsure which one is best for you, read through our buyer’s guide below and then check out the resin reviews again!