Kite line typically has a loop at both ends. You can use a knot or you can sleeve (split) the line. To sleeve a length of line it should be a kevlar or spectra line with a diameter that allows you to insert the sleeve needle.

Personally I only use spectra line (I don't like kevlar lines at all, they are too dangerous) and I sleeve lines beginning with 70kp. On thinner lines you should still put a protective sleeve on the line but it is impossible to insert the sleeving needle.
1.
What you need
A kevlar or spectra line
(>= 70kp)
A sleeving needle
A protective sleeve
Tips 1

Tips 2 2.
Start
Start Start 3-5 cm from the end of the line You need more or less the length of the sleeving needle (ca. 8 cm)

3.
Push
Push the line to make it easier when you push the sleeving needle inside spectra line.
Tips 3

Tips 4 4.
Insert
Insert the needle into the line.
Don't injure the line!

5.
Get the line
Catch the line with the sleeving needle, so you can pull the line through itself.
Tips 5

Tips 6 6.
Pull through
Pull the line through.
Don't destroy the sleeving needle (use your power for the big foils).

7.
Finish A
After pulling the line completely through the core you should get a perfect loop.
Choose the final size for the loop (this is the last time you can modify the length
Tips 7

Tips 8 8.
Push
Push the line to make it easier when you push the sleeving needle inside spectra line.

9.
Insert
Insert the needle into the line.
Don't injure the line!
Tips 9

Tips 10 10.
Get the line
Catch the line with the sleeving needle, so you can pull the line through itself.

11.
Pull through
Pull the line through.
Don't destroy the sleeving needle (use your power for the big foils).
Tips 11

Tips 12 12.
Finish B
Stretch the sleeved line. The end will disappear inside the core.
Prepare for the protective sleeve.

13.
Protect
Pull the spectra line through the protective sleeve.
Tips 13

Tips 14 14.
Perfect
You got a perfect loop!

Copyright 1995/96/97 by Detlef Beyer