Why Did My Lures Turn Yellow?

by BFD Lures on January 24, 2024

Why Did My Lures Turn Yellow?

Regardless of who made your lures or where you bought them, you may have asked this question. Eventually all of us pelagic fishermen discover the sad fact that our skirted trolling lures lures will turn yellow - to varying degrees - over time.

You may also have noticed that the lures you use the most and are out on the boat in the sun, or even collector-grade lures that you have on display, have yellowed faster than others.

Naturally, the clear-coat, white lures show this change more obviously than the tinted and brightly-colored varieties. 

So Why Does this Happen?

Luremakers use different resins depending on preference, availability, and other factors. Whether its polyester resin, epoxy resin, or polyurethane, they are all susceptible to yellowing due to two factors we cannot avoid: sunlight and oxygen.

Exposure to UV Light:

Put simply, ultraviolet light breaks down the chemical structure of resin. UV rays from the sun break apart the molecules of resin and create free radicals. (These free radicals are basically carbon atoms that are reaching about looking for something to bond to after the UV villain separated them from their happy place.) 


When those lonely free radicals find oxygen in the neighborhood, they bond to those O2 molecules. This is oxidation – the combination of a substance with oxygen. In this case, it creates a chromophore: the portion of a molecule that absorbs visible light, causing it to have color. So your once-clear resin now has color, and it’s yellow.

Other Factors:

Other factors such as temperature and humidity can accelerate the oxidation process. And resin, like many materials, undergoes natural aging processes. Chemical reactions between the resin and other components, including colorants and additives, can occur over time, also leading to yellowing.

Epoxy vs. Polyurethane:

Epoxy is notoriously sensitive to UV rays and is somewhat more susceptible to rapid yellowing. Polyurethane tends to be more resistant to yellowing than epoxy, simply based on molecular structure. I could bore you to tears with diagrams and science, but I’ll spare you. If you’re so inclined to see the nitty gritty, look up aromatic vs. aliphatic structures.


What About Additives?

Yes, UV-resistant additives exist. And while they can offer some protection against the yellowing effects of ultraviolet light, it's important to understand that they are not 100% effective. At most, these additives can delay yellowing. But it will still happen, and in the case of high exposure to sunlight and oxygen - which is the life of a fishing lure - it will not delay it for long.

At BFD I have chosen to not use these additives in my resin, for several reasons. One is the added cost, which would increase the cost of the lures for my customers. Another is the handling: these additives are generally noxious, require a lot of extra safety precautions and regulatory compliance, finicky adherence to mix ratios -- and in my experience they are a smelly, poisonous, pain in the tush.

In short, the dubious extension of time that a UV additive may buy is not worth the downsides.

Does it Matter? 

Is a lure that once worked going to flop when it turns yellow? Not likely. Keeping in mind the complicated way that pelagic species’ eyes work, and how very differently they see from the way we see, you can probably assume that a yellow tint is not likely to be a deal-breaker. I’ve seen my 10-year-old lures in places that have a tough time getting replacements (like deep in South America) that are so old, yellowed, and beat up they’re nearly unrecognizable - and they still fish just fine! 

The disappointing side is a collector-grade lure that you can’t replace. If you have a Joe Yee (or even a Jana Special!) on display in your home or office, try to position it away from direct sunlight. If you have spotlights on your collection, avoid using full-spectrum lights.

What Can You Do? 

For starters, know that I use polyurethane resin to make all BFD lures. This buys us a little extra time on the yellowing front than other resins. (I also choose to use poly for its durability: if you drop a lure on the deck or the dock, it’s not likely to shatter.)

Second, understand what causes it, and try to keep those beauties out of the sun as much as you can. Protection from the harsh UV of the sun’s rays is important for everything from your skin to your reels to that beautiful fighting chair - your lures are no different.

If we lived in a place with no oxygen, our lures would never oxidize at all! But until we start fishing on the moon, use your lure bags, kids!