Splicing high tech ropes

Mik_Ravn

Mik_Ravn

Location
Aalborg, Denmark
Hi all, I'm newborn to this site, but have been lurking around here for a couple of years - I love all this geeky info
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So I guess I'd better contribute a bit myself, instead of constantly leeching on all you gurus-on-the-world-of-rope.

I have come across this PDF-file at a (European) website, http://www.fse-robline.com/, giving instructions on how to splice high tech ropes, i.e. Dyneema, Vectran and Aramides. I have attached the file for reference.
In some of the company's high tech ropes, which I use myself, there is an intermediate cover between the outer cover and the core, which optimizes the grip between the two. However, the instructions in the PDF only deal with ropes which consist of a cover and a core. This leaves me wondering what to do with the intermediate cover? Do I taper it (make it thinner) like the core, and then bury it with the core, or do I simply cut it of? Im a bit worried, that if I cut it of, the low friction of Dyneema against Dyneema will make the splice slip and fail.
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Additionally, one is not supposed to bury the cover with the core, but rather cut it of 8 cm's behind point A (at least that's how I understand it)and then sew and whip it at the bury to cover the splice. The company states that on the high tech ropes it is only the (Dyneema) core which is loadbearing, and the cover merely stabilises the core and protects against abrasion. I guess this makes sense.
What do you think of this approach?

Mik

The chime and clatter of aluminium
is like Jingle Bells to me
 

Attachments

You can bury the cover if you want to- but make sure the core get's buried all the way. Like you said, that dyneema core is the load bearing part of the rope, so you don't want shorten it to make room for a cover.

ABout that middle layer. I've had success just pretending it's not there, and putting the core inside itself and having that middle layer run all the way through the eye, then snipping off the middle layer just on the tapered tail.

Now I just pull the core and middle layer out, then separate the two from eachother, then bury the core, do most of the splice leaving the middle layer just hanging out. When the splice is almost done, I either snip it short, or bury and inch or so up into the eye, just so it will be held onto.

Make sure it get's stitched down!

love
nick

ps- i'm not sure if this made any sense at all. Let me know if there is clarification needed.
 
No, it makes sense. Thanks for the quick answer btw, I was kinda expecting you to be the one replying as you appear to be the resident splicing guru ;)

Think I'll go by the marine store tomorrow and get myself a few feet of rope just to try it out. Only thing is it cost something like 10 $ / meter (3 foot)@ 10 mm, so I'd better get it right the first time!
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Do you have a way to have it break tested?

It might be worth pushing the manufacturer for adequate direction.

There are several other people here that can answer this question! I hope to hear what they have to say.

love
nick
 
Actually, I do have access to a test bench with a dynanometer, guess I should test the breaking strength before doing any climbing on them...

I did send the same question to the manufacturer, but it is probably going to take a while before I get a reply. I assume that they would know. On the other hand, their directions for splicing regular dbl braid look quite dodgy to me, as they don't taper the core. Instead they do the bury, and pull the core back out an inch or so away from the base of the eye, simply cutting the remaining core of. Seems like the cover then gets role of loadbearer. Highly suspicious, if you ask me. Check attachment.
 

Attachments

I can't find their directions, can you send me a link?

I've seen some REALLY bad directions published on a few websites. I hope this isn't another!

love
nick
 
Honestly, this is a tricky situation. ANSI says to do what the manufacturer suggests. These you posted have you burying the core only 1.5cm down the throat of the splice. I'm not comfortable with that. These directions don't specify which rope diameters they are talking about. Surely the same directions shouldn't be used for 3/4" rope as would be used for 3/16" rope...or would they?

The high tech splice they do is a version of the core to core splice.

For your rope, I would first REALLY push the manufacturer and ask for direction in splicing this rope. If they don't help, I would (take my business elsewhere, but for now) just splice as I described before, having the middle layer stop in the throat of the splice and not running through the eye.

FWIW- that splicing needle they show is the Selma splicing fid. I have a set of them and am a bit disappointed. They keep messing up my ropes...there is a little notch in the FRONT that keeps grabbing tiny parts of strands and pulling them and making me cut off the rope and start over!

love
nick
 
With regards to the double braid instructions, I would personally go for the traditional tapering and full bury of the core, as it's a tried and tested method. The high tech splice... Well I'm gonna wait for Teufelberger's answer, and then take it from there. I'll have to test the breaking strength regardless.

I've got a Selma fid myself, I have to say that it is a bit finicky to work with. I also have a set of plastic fids which I nicked from my dad - they're completely worthless as they're too thick and bendy, and the friction is just silly.
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So the Selma is the best I've got. For dbl braid, what would you recommend?
 
For what it's worth, the earliest double-braid splices had little or no core bury. The theory was that, with the cover on one side of the eye, and the hollow cover on the other, you had 150% of the rope strength. This theory got a few people killed, as any chafe or eccentric loading tended to make the eye much weaker than the standing part. That's why the current standard was developed, with the core buried 14 diameters or so down the standing part. Unfortunately, that bury makes the splice much, much harder to do, especially if you are using a bulky tool, and/or are working with tough rope. But it's important, obviously.
As for the untapered HM splice shown on that site, tapers not only reduce distortion in the rope, thus improving strength, they also make for less chafe, as there's no pronounced shoulder at the end of the tail. And of course tapers are easier to run home.
Disclosure: I make splicing tools, but the right splice for any rope can be made with lots of different tools.
Fair leads,
Brion Toss
 
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