I typically use 8-10 lb Sufix 832 braid with 7 lb Sunline fluoro. When I first tie an FG knot with this set up, I can lift a 7.5 lb dumbbell off the ground without anything breaking, so I assume I'm tying it correctly. But after maybe 4-6 hours on the water, the knot tends to weaken substantially. Typically, a small fray appears in the braid part of the knot, and I can easily pull it apart by hand.
Typically, I set my leader length so that the knot is just outside the spool of my spinning reel before I cast. I've noticed that if I use much shorter leaders, the knot tends to last much longer. So I think that going through the guides weakens the knot. Is the knot not supposed to pass through the guides? Do the bigger guides near the reel do more damage than the smaller guides at the tip of the rod do? Am I supposed to re-tie every couple of hours?
I'm new to spinning reels and using fluoro leaders with braid, so I'd appreciate any advice. Thanks.