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Picture of Making Two Equal Length Double Spliced Dyneema Lines

The purpose of this instructable is to teach you how to make a splice in high tech dyneema line.

The challenge to hanging things like hammock chairs or paraglider harnesses is that you would like the two line sets to be the same.

It is important that you do your measuring and marking of both lines and line ends before you start splicing.

This instructable will be good splice practice, it is really fun when you get the hang of it.

You will be making two double spliced lines. Hopefully they come out equal lengths.

You will need:

Splicing tools (fid and pusher)

Razor blade or knife

2.5m (98.4in) of dyneema split in half.

Sharpie or fabric marker.

Step 1: Mark your lines.

Picture of Mark your lines.

The general rule is that you want to measure a length of line at 50X the diameter of the line.

For 4mm line for example the measurement is 200mm. (using metric because nice round numbers in this case and the dyneema came in metric)

This is important because you want enough line embedded in the splice to make it maximum strength.

You can take the remaining line and choose your loop size. Mark the line.

could you make a fid out of small bore pipe ? As they are expensive to buy from manufacturers

Hollow metal knitting needles can be modified to be nice fids for single braid ropes. Cut off one end at an angle, cut off the [potentially dangerous] 'point' just created and smooth the edges (300 grit sand paper, followed by 600 grit and then 1000 grit works well for aluminum and brass). The interior diameter should be just large enough to slip your rope into. I'd check out the thrift shops and local garage sales for inexpensive metal knitting needles. Some of the smaller diameter needles are solid; for those you can use fiber strapping tape to connect the needle/fid to the rope. Just use a single layer of tape with the fibers parallel to the axis of the fid and the rope. Don't forget to leave a small gap between the fid and the rope. A solid fid should have the same diameter as the rope.

If you have good metal working skills you can add a little tooth (or two) to the cut end of the hollow knitting needle fid to help hold the rope in the fid. Do an image search on "Seitech Selma" to see what I mean. The Selma fids use a single tooth from the bottom, but it's easier to make two, one on the left and one on the right using a single short angled cut across the first cut and bending the resultant points in slightly.

Jobar0073 years ago

I would recommend marking the second line by using the first as the marking gage. If you make a mis-mark (used the sharpie on one side of the measurement for one rope and the other for the other rope), your lines won't be the same. Marking the second with the first as the gage minimizes any measuring mistakes.

This looks great and is simple to replicate. Do you know if this will work for double braid?

moon_goose (author)  Jobar0073 years ago

Agree! Good call. That is similar to what I do from one line to the next, I measure one, mark it, then just copy the marks over to the new line.

The double braid line has a core, and its a different splice all together.