Why Does Epoxy Hardener Turn Yellow In The Bottle Sometimes?


Why Does Epoxy Hardener Turn Yellow In The Bottle Sometimes?

Hey there, Promise Epoxy pals! 🌟 Ever opened your epoxy hardener and thought, "Huh, why's this looking like a sunset in a bottle?" You're not alone! Let's dive into this colorful conundrum. 🎨

First off, it's all about oxidation - think of it as your hardeners way of taking a deep breath of air. Once it's manufactured, this oxidation journey begins. 🌬️ It's like an apple turning brown; totally natural but not always what you want.

"But wait!" you might say, "I've not even opened this bottle!" Well, here's the thing - even if it's sealed, those HDPE plastic bottles are like yoga pants - they breathe a bit. So, a tad bit of oxygen gets in and starts the yellow party. 

Now, if you've played peekaboo with your hardener and opened the bottle, it's more exposed to our good old friend, oxygen. Hence, it goes yellow faster, especially if you’re dealing with a big bottle.

But here's the kicker - a little yellow doesn't mean it's game over. When mixed with resin, it's like a magic trick - abracadabra, and the yellowing is hardly noticeable! 🪄 However, if it's looking more orange than yellow, like a pumpkin in October, it's time to do a little test batch to make sure your project doesn’t end up looking like a Halloween decoration (unless that's your vibe, of course). 🎃


Pro Tips & Technical Info:

Got a hardener that's gone full-on yellow? Pair it with dark pigments, tints, or dyes. It’s like a new life for your old friend. And for those crystal-clear projects, maybe grab some fresh epoxy resin. Many customers will use yellowed epoxy hardener in their work with dark pigments, tints or dyes; and acquire new epoxy resin for their crystal-clear epoxy resin projects!

If the epoxy hardener is dark yellow or orange in color, the product may have passed its expiration date, stored in extreme temperatures or exposed to UV rays. The epoxy resin should still cure properly, but a test batch is recommended to ensure that the finished, cured results are not discolored to dissatisfaction.



So there you have it, folks! Yellow hardener isn’t the end of the world. It’s just your epoxy showing its true colors. Keep crafting and keep creating wonders!

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