UV Coating Turns Thread Very Dark

All of the Chironomid patterns I am tying have the thread colors deeply darken with I apply UV finish. Watery green thread looks like brown, etc.

I love the durability of the UV but very disappointed with the results no matter how thin the application.

Does anyone have a suggestion how to avoid this. Should a I apply thread color preservative before UV coating?


Active Member
Check that the UV cure material adheres to the Color Preserver. Some coatings aren't compatible.
Its easy to do a colour check on various threads by wrapping a number on a long shank and then coating them all, AND different under body colours can affect the finished colour of your thread.


Active Member
Out of curiosity, if you soaked an uncoated fly in water would it turn the same color as the UV coated fly?
My experience with CP on rods was that it made the colors flat and boring rather than rich and translucent.
Thread changes color when wet even with plain old head cement. Imagine how many fish didn't care

Try white thread to build a couple of layers for the body and the coat the final wrap of thread with a permanent marker before wrapping it forward

Coat the hook shank with White out

Cover the hook shank wit tinsel then tie the fly
Thanks for all the ideas and feedback. I have ordered color preserver and will give that a try.

I have already tied some of the patterns with under wrapping to make the final color thread pop. When the UV is applied it does not make a noticeable difference whether the pattern has an under color wrap.


Active Member
Coat finished fly with superglue/crazy glue first, let dry, then apply your UV resin.
Paint hook with white or silver felt pen marker first, this can really alter the finished look.
What UV finish are you using? I tie a lot of thread bodies and have never had a problem with thread darkening. I do have this problem with Sally's, which is why I don't use it any more for thread bodies. Sally's is fine for bodies made out of tinsel or other body material, but not thread. But neither Silvercreek's stuff nor Loon has ever darkened the thread for me. Adding color preserver seems like a unnecessary step in my opinion.
Silver creek and Loon both have this effect on thread bodies. I have color preservative on the way and will post a photo or two as soon as it gets here. I plan on showing: as tied, wet (water), SH, UV, color preservative and preservative with UV.
More later.
hmmm i only seem to have this problem with Sally’s. I will go back and do some experimenting. Another option is to only tie black bodies..... just an idea. ;)


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Deeply darken or "very dark" - out of curiosity I just wound about four layers of 8/0 olive UNI-thread around a bronze shanked hook and dipped half the windings in H2O. The wraps darkened pretty much like I experience when I coat a head with head cement or when I SHHAN coat a body. Same as the OP suggests, UV resin (both Loon and Deer Creek) darken most thread colors. What I've found is if I want a lighter "olive" midge I use a lighter olive thread. UTC Watery Olive does change color when coated with UV, but it sure isn't a significant change....

At times "purple" is a good color for flies, MFC 685 purple does get a lot darker when coated with resin. Sometimes the trout really like it. I coat the flies for durability (and sheen and because I like it).
Keep in mind that just because the colour changes it doesn't mean that's a bad thing. Fly tying is a creative pursuit. Changing the final outcome by applying uv resin or head cement to a thread or floss body can have effective results in the long run. Many fish get caught on what you may think is an ugly fly. Just because you don't like it doesn't mean the fish won't find it attractive.