**With a larger-diameter fly line, like floating and intermediate lines, folding the line over itself produces a bulge that might have difficulty passing through the rod guides. The most popular method for putting loops in these lines involves using either monofilament or Dacron hollow-core braids. I prefer the latter because it doesn't break down as readily as monofilament. Both types come in different breaking strengths and diameters. A 50-pound-test hollow-core monofilament braid will accommodate most large-diameter fly lines; for Dacron you'll have to look in the 80- to 100-plus-pound range.
In either case, begin the process with a 12-inch section of braid (if you want a larger loop, start with a longer length of braid). Take a 12-inch length of approximately 27-pound-test single-strand wire and bend it in half to form a narrow threading loop. Insert the wire into the middle of the braid approximately 6 inches from the tag end, and push it about 11¼2 inches up inside the braid. At this point, push the wire back out of the braid. Insert the free end of the braid into the wire loop, and then grasp its tag ends and pull it along with the end of the braid back inside the braided line that you ran the wire through. Pull the wire loop and the tag end out, leaving about a 1¼2 inch loop in the braid. It's common practice to insert the tag end into the braid a second time for added security, but it's not necessary. As long as the loop is pulled evenly (which is what happens with interlocking loops), the tag end will not pull free from the braid. To make sure this never happens, tie a nail knot over the section of braid just below the juncture of the loop. Now, regardless of how you pull on the loop, it won't give way.
Once you have formed the loop in the braid, you must work the fly line into the remaining straight section of braid. (With a 1¼2-inch loop in one end, about 5 inches of single-strand braid should remain below the juncture of the loop.) To make the job easier, cut the tag end of the fly line on a bias and work it inside the braid "inchworm style" until you reach the tag end of the loop. Lastly, whip-finish or nail-knot the tag end of the braid over the fly line.