Why Epoxy Resin Can Turn Yellow

If you have had any experience working with epoxy resin products, you have most likely noticed that it can tend to yellow over time. While this discoloration isn’t necessarily a sign of a problem, it may be an undesirable outcome. Understanding why epoxy can yellow is the first step to making sure your project retains its color and clear coating for the length of its lifetime. 

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Why Epoxy Turns Yellow

Epoxy resin turns a yellow hue due to exposure to a myriad of elements. High temperatures, excessive amounts of water, and UV light can all cause the epoxy to change from clear to yellow in tint. Once the epoxy has turned yellow, there is not much that can be done to reverse the discoloration process; however, it is possible to reduce its impact and prevent the epoxy from yellowing even further. 

Epoxy hardeners can also experience a yellowing discoloration that compounds the epoxy’s off-color issues. While issues with hardeners may not have as much impact as the actual epoxy discoloration does, it is essential to understand that the trouble can be with both products’ reactions to elements. However, not all forms of epoxy turn yellow, and it is possible to purchase specially formulated epoxy resins from ArmorPoxy that discourage discolorations. With this being stated, most forms will change colors if exposed to the following conditions. 

Extended High Temperatures

Exposure to high temperatures for an extended period can cause the epoxy resin to become discolored. This issue tends to happen most if you leave the epoxy resin supplies in an environment that is not climate controlled where they can be exposed to heat. It is also detrimental to the final project if the finished product lies in an uncontrolled environment. 

Sustained Water Exposure

You should always store your epoxy products in a cool and dry place, preferably indoors. If epoxy products are stored in wet areas, or you open and close containers in damp atmospheric conditions that allow for moisture to build up inside the container once closed, your finished product can be apt to yellowing. Always work with epoxy resin products with moisture levels in mind to maintain their original integrity. 

UV Light

Without a doubt, exposure to UV light is the most common reason epoxy resin can yellow.  The impact that UV light rays have on epoxy resin over time excites the polymers’ molecules, causing them to break down. This natural effect of light exposure begins immediately when the resin is exposed to light. It may take quite some time for the yellowing to become visible; however, the longer the epoxy resin is exposed to the light, the worse the damage will become. 

Final Thoughts

While epoxy resin’s yellowing is unsightly, it poses no risk to health and is not harmful to the product itself. Always purchase high-quality epoxy resin products through ArmorPoxy to ensure the best results for projects.