The albright knot
This knot is used to attach two lines of different diameters together. Often used in fly fishing for attaching the thin backing line to thicker fly line. In recent times it is being used successfully to attach modern braided lines to monofilament or fluorocarbon. It provides a very strong connection and is relatively easy to tie with practice.
Instructions
1. Loop the heavier line. Pass the lighter line around the formed loop. 2. Make approximately 10 wraps with the lighter line wrapping from left to right. Hold these wraps in place. On the 10th wrap, come around and then through the remaining loop. Taking the standing line in your right hand pull gently as you push the wraps with your left hand towards the closed loop, keeping the wraps together. Pull the tag tight then pull on the standing part of both lines until the knot is secure.
3. Trim the tag ends of the knot.
Instructional Video
Like I always try to do I have found a video that also shows the process very clearly.