Sage 6126-3 Performance
Nevada Caster,
The way I extended the butt on my rod was simple and direct, I hired my friend at the local fly shop to do it for $25 or $30. Actually, the technique he used was pretty straight forward and it wouldn't be too difficult to do it yourself but in view of how much these rods cost I really didn't want to risk screwing it up so I could save a few bucks.
Anyway, should you be of stouter heart than I, here's how he did it. Using a hacksaw he cut off the butt behind the real seat. The exposed rod blank is hollow. He then selected a tapered piece of scrap graphite rod that was long enough and thick enough to slide inside the hollow of the blank until it fit snug, and yet the internal graphite sleeve extends out of the blank far enough from the blank/reel seat that you have enough stock to build a cork butt upon it from pieces of cork rings. This internal graphite piece has to be the right diameter to fit snug enough inside the blank that once epoxied in place it will form solid continuous backbone within a good portion of the grip. Don't epoxy anything yet. Now once the internal graphite sleeve is fitted, he marks the exact point on the graphite sleeve where it exits the blank at the end of the reel seat.
This is the spot where the top or last cork ring will end at. Removing the graphite sleeve, he builds a cork grip by scratch by stacking the cork rings one upon the other from the butt end piece up, and stopping at the spot marked on the graphite sleeve.
Then he inserted the part of the graphite sleeve that remains exposed (the end that will eventually go into the rod blank end) inside a drill chuck, and he shaped the butt to the desired shape with differing grades of sandpaper from coarse to very fine. One reference I saw on this suggests using a bastard file to do your rough cuts the finalizing your tapered shape with #36, #80, and #120 sand papers. You may wish to look at "The Care and Repair of Fishing Tackle" by Mel Marshall for some good photos and descriptions of his techniques in this regard.
After the desired cork butt shape is created, the sleeve is removed from the chuck, coated with epoxy, inserted into the blank and snugly seated tight right up against the end of the reel seat.
Hope this description is of some use should you end up being a braver lad than I. John