I built a 7' 6" 4WT fly rod form a 4pc IM6 blank. When I cast the rod it oscillates at the end of both the back and forward cast. I finish the forward cast and the rod oscillates fo several seconds. Any sugestions?
Thanks,
John

About the only thing you can do to stop it is to remove weight. Some of that is going to be impossible to remove, as it's part of the blank. But if you've got guides that are too numerous or too heavy, that can certainly contribute to the problem.

Most modern graphite rod blanks have reached the point where long periods ("several seconds") of oscillation are not evident. Most deflect, "bounce" once and then return to straight.

I don't know how you built out that blank or even what brand blank you have. But noticeable oscillation that goes on for "several seconds" after a cast is not normal in most cases.

.............

John,
What you are seeing is called the damping period. Tom is right on, it is very unusual for modern graphite rods to have a long damping period. It was a much bigger problem with older glass rods. It will be primarily a function of added weight. I would do as Tom says and look closely at the weight that you have added and pay particular attention to weight that is added toward the tip of the rod where it will have a much larger effect on this.