Hey Duffin Boy,

For the type of epoxying you did, I'd
recommend a quick dry epoxy such as 5 minute
epoxy. Make sure it's up to room temp and
over 70 degrees. Mix thoroughly according
to directions. Mix a small amount first and
allow it to cure on a piece of wood or paper
plate or some such to ensure it is fresh and
works. Then mix a batch for your actual
flytying. It may have exceeded shelf life,
been too cool, or even leached materials
from your fly retarding drying. Warm
regards, Jim