Tying your own fly fishing leader allows you to customize it to match the conditions you find yourself in and the size of trout fly you are casting. It also is easier to make repairs to the tippet.
A leader is made up of three sections: the butt, the taper (or body) and the tippet.
The butt section is made from a stiffer line and makes up about 60% of the length of the leader. The butt section needs to be stiff enough so that the line will not collapse and fold over during your cast. It also needs to be limp enough that the line will roll over and transfer the energy to the body section and the fly. A butt section of .020 to .026 is commonly used.
The body makes up about 20% of the leader and needs to be a step down in diameter. It should be about 60% of the diameter of the butt section.
The tippet makes up the last 20% and is the smallest diameter and therefore the most fragile. The tippet will need to be about 16 to 24” in length and sized for the fly you are using.
A perfection loop is used at the butt section so you can change fly fishing leaders if needed. This makes it easy since most fly fishing lines now come with an end loop. Learn how to tie a perfection loop.
A double (or triple) surgeons knot is used to tie the butt section to the body and the body to the tippet. Learn how to tie a surgeons knot.
The blood knot can also be used to tie the body sections of the leader. Learn how to tie a blood knot.
Mono-filament is the most common material used for trout. It comes in many sizes and weights. Maxima brand is my first choice.
Fluorocarbon is a new synthetic material that is nearly invisible in water. It is more expensive than monofilament and it is more resistant to abrasion. The jury is still out on whether it is worth the extra cost.
A mono/fluorocarbon blend made by P-Line is a blend of the two materials and like fluorocarbon it is up for debate whether it is worth the extra cost.
If you are new to fly fishing, monofilament should work just fine for everything you will be doing. Save your money, use monofilament and tie your own fly fishing leader.
When fly fishing for trout in small brushy streams you should use a short leader about 6 feet long. In streams that are 15 to 20 feet wide and where the fish are not spooky you should use a leader from 7-1/2 to 9 feet long.
When fly fishing lakes with floating lines, in streams that are low and clear, or if you are fishing very small flies use a 12-foot leader.
Whatever you do, always check your leader for abrasion and knots. Leaders suffer a lot of abuse because they are often rubbing on rocks and looping into “wind knots,” which will weaken them by 50%.
Most wind knots are caused by an error in your casting style. More information on Fly Casting.