I normally use surfboard wax to coat the lines of my kite so the lines don't fray so quick when they are twisted around each other you as you loop the kite ,
I couple weeks back a mate noticed me waxing my lines and he told me about A product that coats not only is the top of the lines by right through inside and out.
He told me that he got it from- fixmykite.com.au
After three weeks, which would be about 7/8 Kite sessions The lines are still crazy slippery.
The other benefit about this product is that the wax coating on the lines Is that they separate so much easier as you unwind them off the bar to set up the kite.
I totally recommend this product to anyone who would like to Prolong the life of their kite lines.
2012 ozones
flown to the absolute shidt house n back on my kids life I've never washed n wax,d
still like new, in 5 years re post
If it's liquid enough to go on doesn't that mean ebrasive sand and crap is going to stick to the lines also making things worse??
Select to expand quoteSmithy said..
If it's liquid enough to go on doesn't that mean ebrasive sand and crap is going to stick to the lines also making things worse??
The surf boat wax I used to use on my lines got sand stick to the lines so I used to dip the lines in the water after a sand launch.
This stuff is slippery when dry no need to rinse how can something stick to something that's slippery. 
