Will epoxy resin turn yellow over time?

Deep pour Epoxy resin

Why Is Epoxy Resin Turning Yellow With Time?

Epoxy resin is a popular material used for various applications such as coating, casting, and adhesive bonding. However, over time, it is common for epoxy resin to turn yellow. This can be concerning, especially if you have invested a lot of time and money in your project. In this article, we will explore why epoxy resin turns yellow with time and what can be done to prevent or reduce yellowing.

Why Does Epoxy Resin Turn Yellow?

Epoxy resin turns yellow due to a natural process called oxidation. Oxidation occurs when oxygen molecules react with the molecules in the resin, causing a change in color. The yellowing process is typically more noticeable in the hardener (Part B) than in the resin (Part A). This is because the hardener is more reactive and susceptible to oxidation.

Additionally, the yellowing process can be accelerated by exposure to UV light, heat, and humidity. Cheaper raw materials used in some epoxy resin products can also contribute to faster yellowing.

Will All Epoxy Resin Turn Yellow?

Yes, all epoxy resin will yellow over time. However, some will have better resistance than others and can take up to several years before any noticeable change in color occurs. At Chill Epoxy, we use premium raw materials in our products, which offer better resistance than most casting epoxy on the market. Our clear epoxy resins have been specifically formulated for indoor applications and are the highest UV-resistant epoxy resins available.

What Causes Epoxy Resin Hardener to Yellow?

The yellowing process of the hardener (Part B) is due to a natural oxidation process that occurs once the epoxy resin is opened. Fast-setting (reactive) epoxy solutions tend to yellow faster than casting systems. At Chill Epoxy, we are currently working on an R&D program to study and eliminate as much of this oxidation process as possible in our fast-setting hardener.

What Is CHILL EPOXY Doing to Reduce Yellowing in Epoxy Resin?

At CHILL EPOXY, we are committed to providing superior products and continuously researching and developing new ways to improve them. We are currently working closely with the biggest raw materials manufacturers to reduce the yellowing of hardeners in our products.

Our chemists are testing new avenues and studying the reaction of certain raw materials. Cheaper raw materials tend to yellow faster than more expensive ones. Therefore, we only formulate our epoxy systems with the best raw materials. Our business model has always been to offer superior products and never to cut prices to offer commodity products.

Chemistry behind cheap raw material and yellowing

In addition, we package our products in Italian metal containers instead of cheap plastic “gallon” containers. Plastic can breathe, allowing air to come in contact with the hardener and accelerate the yellowing process. Our metal containers with double-seal caps keep our epoxy fresh and unexposed to UV.

We also package our epoxy with a nitrogen blanket to preserve the epoxy longer and slow down the yellowing process when unopened.


Q: Can I prevent epoxy resin from turning yellow? A: While it is not possible to completely prevent epoxy resin from turning yellow, using high-quality products and storing them properly can slow down the yellowing process.

Q: How can I store epoxy resin to prevent yellowing? A: Store epoxy resin in a cool, dry place away from direct sunlight and heat sources. Keep the container tightly sealed and avoid exposing it to air.

Q: Can epoxy resin be restored to its original color after it has turned yellow? A: Unfortunately, once epoxy resin has turned yellow, it cannot be restored to its original color. However, using high-quality clear epoxy resin and storing it properly can slow down the yellowing process.


In conclusion, epoxy resin will turn yellow over time due to oxidation, but using high-quality products, storing them properly, and taking special care in packaging can slow down the yellowing process. At CHILL EPOXY, we are committed to providing the best products possible and continuously improving our products to meet the needs of our customers.


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