You pour epoxy with perfect clarity, it dries beautifully, but after a few weeks, your once-clear resin may turn into yellow resin, which can be frustrating to see. Epoxy yellowing is one of the most common issues resin artists and makers face, especially in the UK, where we deal with a mix of damp weather and occasional bursts of strong sunlight.
The good news? With the right knowledge of the science and the application of the correct methods, yellowing can be eliminated or at least reduced. This manual discusses the reasons which make epoxy resin yellow and provides you with tips you can use in practise so that your resin projects retain their crystal clear appearance many years into the future.
The main cause of epoxy yellowing is the UV rays. Epoxy also breaks down gradually when in the sun, just like fabric and fades into a dull amber colour.
High temperatures speed up oxidation, a chemical reaction where resin molecules break down and discolour. This is common on tabletops, coasters, or countertops exposed to kettles, mugs, or sunlight through a window.
Not all resins are formulated the same. Cheaper products often lack UV stabilisers or non-yellowing additives. These may look fine at first but quickly degrade with exposure.
Humidity and moisture can interact with epoxy hardeners, leading to cloudiness and early discolouration. In the UK climate, this factor is often overlooked.
Start with the right base. One of the stabilisers added to a high UV-resistant epoxy resin reduce the process of yellowing remarkably.
An epoxy coating is not sufficient when it is under sunlight. Coating with a UV blocking topcoat, e.g. polyurethane, acrylic, or automotive clear coat is your project sunscreen.
Placement matters. The so-called UV resistant resins will all turn yellow after sometime when left in direct sun.
High heat accelerates chemical breakdown. Common mistakes include:
Hack: On surfaces such as countertops, one should always use heat-resistant mats or coasters to increase the lifespan of the finish.
Improper resin-to- hardener ratios can leave epoxy chemically unstable, which speeds up yellowing.
Even untouched bottles of resin may turn yellow in storage in case of improper handling.
It is too late to prevent sometimes. Even when your epoxy is already yellow, there is still a possibility of saving your project.
In case the yellowing is not severe, one can add a tint or pigment to cover the discolouration. The appearance can be refreshed by using metallics, opaque colours or alcohol inks.
River tables are a popular UK project. Because they are large, they are often placed in well-lit living rooms. Without UV protection, that “crystal clear” river will eventually turn amber.
Best practice:Yellowing of epoxy is very annoying, and it does not necessarily spoil your projects. By using the correct resin, protective finishes and maintenance of your resin art, furniture or jewellery, you can significantly lengthen the durability of clarity and beauty of your piece.
Buy smart, protect well, and your epoxy resin projects will stay crystal clear for years.
Explore our UV-Resistant Epoxy Resin Kits to keep your creations protected from yellowing.
Jack
How to prevent yellowing of epoxy resin was something I was really worried about, and this guide answered all my questions clearly. I found the tips easy to follow and very useful for keeping my resin work clear and looking new.
Dec 17, 2025