For those of you that tie in a separate butt section.

[deepcreek]

'When using an off the rack leader what diameter is your choice and is their any rules for length. As you can see, I am still at it. Interestingly enough this same question asked of several fly shops generated a simply "duh" which i am perfectly capable of uttering myself.

[billhouk]

The diameter of the butt depends on the diameter of the tippet. I have a spreadsheet of patterns for tying your own leaders. Send e-mail via PM and I'll send you a copy. I'll defer the length question to those with more experience. I usually carry 9' and 7' leaders. But, I'm sure there are other opinions on length.

[Bamboozle]

Deep:

Are you talking about a separate butt section, permanently attached to your fly-line for the purpose of attaching a leader to?

If so, most folks go with something that is close to the diameter of the fly line they are attaching it to which means it will end up somewhere between .024 and .019. When I used to do it, I typically opted for .020 for most line sizes and .022 or larger for 8 wts and above. Length is subjective but because I did the loop-to-loop thing and didn't knot my leader to the added piece, I kept mine around 4"-5" long.

If I expected to cut off my leader from time to time I would probably make it longer, depending on the knot I was tying and how much material I need to tie it. I can tie a blood knot with 1" of waste so something like 8"-10" would last me a long time. Obviously YMMV.

If this isn't what you were referring to, as Emily Litella said:

[hairwing]

I'll throw this up for your thoughts. I say you can go long with your leader as long as you've got some fly line weight out the end of the rod tip to make comfortable casts. So in my case if I have the magic 30 ft. of fly line past the tip I feel comfortable with long leaders 12 to 18 ft.. Leaders that long will not fish well with short casts when you only have 5 to 10 feet of fly line past the tip. There just isn't enough fly line weight there to bend the rod.

On butt dia. let me say that I'm more apt to fish on top, and to beat the fly dragging in the current I like to pile a leader (smaller diam. butts), but I also like to be able to put some power into it ( bigger stiffer butts) for curves and tucks. So I compromise with a butt dia. of .019 and it works for me. So maybe you have to look at the type of fishing that you do. I'll make a general statement and say that if you want a slack line presentation = smaller butt material, if you'd like a straighter leader laying on the water = bigger stiffer butts. When I toss a streamer to the far bank and want instant control of my fly, or fishing stillwater when I need to impart action to a fly, that's when I like my leader to lay out nice and straight, but I make this happen with the speed in the cast and live with my .019 butt.

General rule for sizing the leader butt diameter is 2/3 the end of the fly line. Most of the lines I have measured that I use are about .033 which means I should use a leader butt of between .021 and .023. As you can see I don't exactly follow the rules. That's a good advantage to making your own leaders. You can find out what fits your style. Once you match what you want a leader to do, as I did in my case, you should be good to go for 40 years.

Add one more caveat and consider the taper in the fly line itself. What I think we are all after is to control the speed of the rig when it comes to the water surface so that it lands with as little disturbance as possible. The final presentation has to slow down to a crawl but still get to where we intended it to. This is an artful thing, but fly lines have different front tapers which can confuse the normal setup. In my case I have lines which have 4 ft. front tapers and I have lines which have 8 ft. front tapers. You can see that the shorter taper puts more umph into the leader and the longer taper takes some of that power away. You have to be aware of this and juggle the characteristics to suit yourself and figure these tapers into the length of your leaders.

Finally, if this is a connection problem of the leader and fly line you are struggling with I finally went to a fly line loop connection because I have way to many rods to fish with and I fish the same basic leader on them all and to me it makes no difference what the butt size is, I just loop my .019 butt together anyway and now I can swap a leader from one line to the next rod.

Enjoy the puzzle.... And all the different knots your are going to learn how to tie.

[Silver Creek]

I will nail knot the thickest and stiffest mono I can to the end of the fly line. I tie a perfection loop to the end of that, and then connect the leader butt to that with a loop to loop connection.

Most leader butts start with a .020 - .022 inch mono. Using a 5 wt fly line as an example, it would be ideal to nail knot a .022 section of mono to the end of the fly line. However, I have been unable to nail knot any Maxima Chameleon that is thicker than .019 to the end of a 5 weight fly line. Like Hairwing, I end up using a .019 diameter because that is the thickest Chameleon that I can nail knot onto the end of the fly line. Keep that section of mono about 4" or so and you will not notice any hinging at that connection.

I've read the 2/3 rule of thumb that Hairwing mentions as a rule for diameter changes in adjacent section of mono or building a leader. It is based on the fact that a 1/3 drop in diameter results in a 50% drop in linear mass when the materials that are tied together have about the same mass density. The Borger Uni-Leader uses that formula.

The end of a fly line varies in mass density (specific gravity) with floating line having less mass density than mono and sinking lines having a higher mass density. I will speculate that since the mass density of a floating fly line is less than mono, you can drop the diameter a bit more than 1/3. I think that is why the .019 works well for floating lines of 5 wt.

[Buddy Sanders]

You can really get into this...

Lots of variables. If you really care to break it down, you can find advantages to using different butt diameters and leader lengths based on:

The fly you fish. Size, type (streamer, nymph, dry...etc.).

The type of fishing you intend to do. Surface, subsurface (upstream, down, dead drift or animated.)

The conditions you might face. Water clarity, water depth, current speed, stillwater, wind velocity and direction.

The type fly line you are using. Floating, sinking (different sink rates?), sink tips.

The type of fish you are fishing for. Trouts, bass, salt or freshwater, toothy critters, etc..

I'm sure I missed many of the options out here, but I'd say it would be safe to say that I could come up with well over 1,000 leader butt diameter/leader length combinations and be able to justify a reason for using each of them under certain circumstances...and that would be WITHOUT considering tippet strength...And for EVERY one that I would consider 'ideal' for a certain application there would be at least fifty people that post here regularly that would use something different under the same conditions.

In any event, there is no 'correct' answer to this, only that if it 'works' for you, then you have it 'right' for YOU.

I really beleive that a 6 foot piece of 4 pound mono would work just fine for 99% of the trout fishing done in the world...but I really like tinkering so I don't keep it that simple.....

Good Luck!

Buddy

[hairwing]

Sweirbert and Swiebert or Swiertzer ( I know that I misspelled their names) have dazzled us with nylon leader formulas. All well and good , but I got tired of the idea that they were needed real fast in my early fly casting days. I started with leaders that were a guess-timation of the likes of Al McLane and Charles (don't call me Charlie) Ritz who both would have conceded that the formulas for their design were based on feel and not science. Hence we all followed with the 60-20-20 formula for most contemporary designs.

We catch fish on these leaders which for the most part are designed for the presentation of the dry fly on moving water and we will be forever adjusting the butts, the mid tapers and the tippets to our unending satisfaction in the hope to achieve the ultimate drag free drift. But Ritz and McClane have already given us that part. We have to learn how to CAST and present the fly!

I don't think a leader is so important, just so long as the fly has a drag free drift.

[deepcreek]

Thanks everyone but I have decided that that Emily lady is pretty damn smart and even the "duh" of the fly shops is understandable.

[Chuck S]

What you are after is a smooth transition from the line to the leader. Go with somewhere around that 2/3 diameter of your fly line tip, but many including Lefty last time I heard was using a leader material that matches the flex of your fly line or fairly flexible, not stiff. You can certainly balance the stiffness and the diameter to match the flex but I like to keep the diameter up in this pre-butt as then you can get a smoother transition through the butt and midsection to reach the tippet material as the leader turns over.

[Steven]

Get some Maxima Chameleon as equal to the diameter of the store-bought leader's butt section you usually use as possible. Nail knot it to the fly line (using a nail knot tool, I can do Maxima .022 and I'd bet I could do thicker). Make this butt section about 6" long, including surgeon's loop (a perfection loop is a total PITA with Chameleon).

Attach store-bought leader with hand-shake connection.

Go fishing.