No, the Castwell knot will not work in reverse.
For those of you going through all the nail knot perfection loop work, I suggest you at least try the Castwell knot one time.
I use nothing but furled leaders and they last a long long time. I certainly do not have to change leaders every time I go fish. I use tippet rings on the fly end of the leader.
Castwell knot uses the fly line to tie into the loop of your leader. Of course the furled leader already has a loop…just as many store bought leaders have. Works on both.
If I want to change the leader, simply cut the fly line at the knot. You are only loosing about 1/4" of fly line if that much. And tie on a different leader. I use UV Knot Sense to cover the knot…in hopes it does not snag on the guides. I have not fished enough to know if it is going to hang in the guides yet. I haven’t had a fish on where the knot has come into the guides yet. So I can’t swear to that. (I use an 11’ rod)
But you do not need a tool, no perfection loops, just tie the knot, clip off the tag and go fish. Leave the leader on the line and use it over and over and over…etc. It is not going to wear out…or wear down like a store bought mono leader.
It is so simple, so easy, I cannot imagine going through all that trouble. Even if I lose a fish or two I wouldn’t switch back to all that other bother. I only do C & R and I don’t land every fish I hook into anyway. If I land him I am going to turn him loose without taking him out of the water. If it hangs up in the guide, so be it. It is only going to break the tippet…if it does that even. I’ve had enough fun with him by that time anyway, and I am just going to turn him loose.
The Castwell knot is so simple you can probably tie it in about 15-30 seconds, can tie it without a tool, probably could tie it in the dark…with just a tad of light. All that nail knot and loop business…not for me. No way in heck.
BTW…just for fun…I figured out how to remove the mono leader that comes on an L2L and install a furled leader on it! Sweeet. But I haven’t fished with it…I don’t trust them. But I can do it, totally without affecting the integrity or strength of the original connector at all. I just prefer to tie the line to the leader with the Castwell knot. It is so simple and quick…I don’t need the L2L.