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Line stretching and knot problems..



I've been following this thread about line stretch and knot problems with 
some interest and figured it was time to put in my $0.27 worth.. When I 
first started with this Spectra material, I went through a very parallel 
learning curve to that some of the folks out there on the net are 
experiencing now.. So what follows are some of my experiences gathered from 
making/selling pre-stretched, matched Spectra line sets.. If any of my 
customers or fellow flyers show any interest in making their own line sets, 
I'll show them everything I've learned, give them some sleeving material 
and a piano wire fid, then they can buy bulk line (from me or whoever), 
usually somewhat less costly than ready-made line sets..

First, I match the braided Dacron sleeving to the Spectra line as follows..

50#  Spectra  --->  30# Dacron     
80#  Spectra  --->  50# Dacron
135/
150# Spectra  --->  80# Dacron
200# Spectra  ---> 130# Dacron
300# Spectra  ---> 130# Dacron
400/
500# Spectra  ---> 200/250# Dacron
or I'll get some 3mm static line from a mountaineering shop and strip the 
core out of it and use the braided shell for sleeving for the heavier lines..

   I cut the sleeving to 12" to 14" _equal_ pieces.. Exact measurement 
isn't real critical but _equality_ is.. I melt the ends of the dacron in a 
flame to keep it from unraveling, then using a fid of .010"-.015" diameter 
piano wire doubled over I poke the folded end of the piano wire through the 
side of the braiding sleeving just beyond the melted end and run it down 
the center of the sleeving, exiting through the side just before I get to 
the opposite melted end.. I usually string all four pieces of sleeving 
required for a line set on the fid before starting to sleeve the lines..

   Next item is to measure/match/stretch the lines to length.. Because I 
make a fairly large number of line sets over the course of a season, I buy 
Spectra in 1000'-3000' spools.. The major advantage to this is that when I 
make line sets I'm assured that both sides of the set came from the same 
manufacturing batch and will have the same stretch characteristics.. If you 
buy 100' or 150' spools of line to make 100' or 150' line sets, you have no 
way of knowing that they came from the same run lot of line. Because of 
this, if your local supplier doesn't have bulk line available, get the 
longest spools you can (like 300') so you know that both lines came from 
the same batch..

   To measure, I have a 100' fiberglass tape in my line bag, but pacing off 
the length will be OK for the average weekend flyer.. 

   To pre-stretch the lines I use a stout piece of rope and a large 
carabiner(sp?), looping the rope around a lamp post or tree or trailer 
hitch and tying it off.. Clip the carabiner to the rope loop and pass the 
bitter end of the Spectra line through the carabiner. Then I use a 
screwdriver or stake as an axle for the line spool and wrap the end of the 
Spectra a few turns around the stake, and walk the line out to whatever 
length I'm making line sets.. For discussion sake, I'll use 100' for a 
number. At the 100'length, I'll cut the line away from the spool.. At this 
point I have a 200' piece of Spectra that runs from me to the carabiner and 
back to me with 2 bitter ends.. I pass the end of the Spectra through the 
loop in the piano wire fid that has the sleeving strung on it, double the 
Spectra over, and work off one piece of sleeving from the fid over the 
Spectra, running the sleeving a foot or so down the line. Repeat this for 
the other bitter end of the Spectra. Then I burn the ends of the Spectra to 
from a lump that's difficult for the sleeving to get back off of. Then I 
'milk' the end of the sleeving even with end of the Spectra and grip both 
firmly then milk the opposite end of the sleeving away from the bitter end 
to make the sleeving fit as tightly as possible to the Spectra and tie off 
a loop with a figure-8 knot.. I've found that a figure-8 works better (for 
me) than stacked overhand or double overhand or surgeon's knot. Now I have 
the same 200' piece of Spectra, sleeved, looped and knotted at the bitter 
ends.. Now I'll again use the stake or screwdriver (round, smooth shank, 
please), passing it through the loops in the Spectra line and pulling with 
a smooth even pull enough to get the initial stretch out of the lines and 
holding some pressure on it for a little while.. Here's where some sense of 
feel comes into play.. Obviously, you can't lay into 50/80# line as hard as 
you'd get into 300# line.. One line manufacturer suggested to use about 50% 
of the line's rated strength as a stretch load. Now, stake the looped ends 
of the line (loosely, you'll need to get the other [bight] end off of the 
carabiner) and go back to where you started with the rope/carabiner 
combination. Unhook the spectra from the carabiner and use another stake  
to pull the line so it's even and this way you can find the _exact_ center 
of the line loop and cut it into 2 _equal_ pieces. Sleeve the 2 new bitter 
ends as before and make loops with your choice of knot.. Now you have a 
pre-stretched _matched_ set of lines that are ready to wind up, or fly 
with.. I find that all I use the Moran Equalizer for is to periodically 
check my work.

Before winding or flying, I mark both ends of one line with a red magic 
marker to use as the left (or right) line, as your style dictates.. I know 
that most kite folks use red for right, but I've been around boats and 
aircraft all of my life, and red is the _left_ navigating light under that 
convention.. Whatever your preference, if you use the marked line 
_consistently_ for one side, then you don't have to stop and think about 
which hand is for which line, you can just pick up your lines and launch.. 
It'd easier to fly the twists out of the line than to mess with them on the 
ground, IMHO..
                                                          
Ob. Disclaimer:

I am a stunt kite dealer and carry some of the above mentioned
product(s). As such, my opinions may tend to be somewhat subjective.

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Good Winds and Tight Lines!

Dan Rubesh
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