Splicing Oplux

[CZMark]

I don't know why I seem to be obsessed with splicing this rope, maybe I hate admitting defeat. Today, I did a Class II Double Braid splice again, but pulled the yellow inner core out at "mark 2" on the core. This enabled me to pull the inner core tight enough to allow burial of the core into the core. Before milking, I cut/tapered the inner core at mark 2 and milked it into the core. Now the inner core is within the splice and should add strength (my previous class II splice broke the rope where the inner core ended ahead of the splice). This may well be the ticket.

Too close to season to have it tested, will have to wait until spring.

 

[maddog887305]

Awesome stuff guys.

 

[Njjb122]

How do you splice oplux then i never new all the different types of ropes just the common ones used for boating and i was always able to splice them easily i just bought 30' of oplux from ewo in hopes to splice eyes in for my lineman and tree tether to streamline them

 

[Jrybicki]

How do you splice oplux then i never new all the different types of ropes just the common ones used for boating and i was always able to splice them easily i just bought 30' of oplux from ewo in hopes to splice eyes in for my lineman and tree tether to streamline them

Please read this thread in its entirety but particularly page 2. We came to the conclusion that while it is "possible" to splice, we found that modified splices were needed and only then was oplux/canyon lux able to retain 75% of its breaking strength. Splicing is preferred in the marine world because it cuts down on rope bulk and when done on known splicable rope can retain up to 90% of the ropes breaking strength. While 75% is okay, that's assuming the modified splice was done correctly and the risk isn't worth the very minimal savings in knot bulk. You are much better off tying a figure 8 on a bight or a double fishermans/scaffold/poacher knot to secure your oplux.

 

[Brocky]

I did a 72 diameter straight bury in RescTech that tested at 5183 lbs. using Samson’s reduction and tapering instructions for Class II single braid. I removed the inner core and reburied the length to match the core reduction, tapering at the end. From what I’ve read it is important to try to taper to a final fiber for the most strength retention. Mine broke in between the two splices, so the rope itself broke, the ends were close, might have done better with more space between them.
Below from the left is a double braid, one and only, a locked brummel and bury, the tested piece, and the splice in Oplux.

Again from what I’ve read, most knots slip, and those that don’t only test to 50% of the break strength at most, a cover does little to help.

 

[Jrybicki]

I did a 72 diameter straight bury in RescTech that tested at 5183 lbs.

Tested great but dang that's a long bury lol almost 2 ft... how was that to bury? Also for removing the inner core, was it only removed from the tapered portion or the full length? I'm also a bit curious on the brummel splice with the double braid core spliced into not sure if rescue tech or oplux.

 

[Brocky]

The 72 diameter bury is what has tested to retain the most strength, mostly used on standing rigging on a sailboat. Rope manufacturers usually recommend 60 diameters, and I’ve read of experienced riggers saying 48 is enough. Burying wasn’t too bad, but I wonder if the dyneema outer core is blended with polypropylene, which reminds me of Velcro, it doesn’t want to slide easily.
A locked brummel only gives security that the bury doesn’t come out, and reduces strength by 10%, stitches near the eye will do the same with little or no reduction in strength, also having a cover helps with this.
I extracted the inner core where the buried core tail would end and reinserted, crude drawing below.

 

[FireInMyBones]

I did a 72 diameter straight bury in RescTech that tested at 5183 lbs. using Samson’s reduction and tapering instructions for Class II single braid. I removed the inner core and reburied the length to match the core reduction, tapering at the end. From what I’ve read it is important to try to taper to a final fiber for the most strength retention...

Impressive strength retention! I'm coming from rock climbing and I'm familiar with the Class II double braid, but not the Class II single braid. I just bought some Resc Tech and will be using knots until I've played with some of the extra rope that I ordered. I always found the taper to be vital in securing strength retention.

The 72 diameter bury is what has tested to retain the most strength, mostly used on standing rigging on a sailboat. Rope manufacturers usually recommend 60 diameters, and I’ve read of experienced riggers saying 48 is enough. Burying wasn’t too bad, but I wonder if the dyneema outer core is blended with polypropylene, which reminds me of Velcro, it doesn’t want to slide easily.
A locked brummel only gives security that the bury doesn’t come out, and reduces strength by 10%, stitches near the eye will do the same with little or no reduction in strength, also having a cover helps with this.
I extracted the inner core where the buried core tail would end and reinserted, crude drawing below.
View attachment 43157

This looks like the Class II Double Braid, but the above post mentioned a single braid long bury. I intend to play with trying to maintain the inner core, but I'm not overly optimistic. This drawing is helpful in seeing what was most successful.
I have the means to stitch near the eye with a ballpoint needle for the task. How did you clean up the cover on the double braid? Did you lock stitch only? I'm thinking of lock stitching under heat shrink.

 

[Fl Canopy Stalker]

Well in theory we could compare against known percentage strength retention for common knots in the same application. For any situation where I would be splicing oplux I would probably be replacing either a figure eight on a bight (5 inch eye) or possibly a scaffold and/or poachers knot (tight eye).

Worst case scenario we're looking at 75% retention. Canyon lux is rated to 24.2 kN, so 75% of that puts us in the neighborhood of about 18 kN. That's a difference of 4.5 kN from the tight splice (coming in at a whopping 55% retention) or about roughly 1000 lbs of force weaker.

Considering that splices consistently see retention anywhere from 90-100% retention, this is sub-optimal.

Just curious do you truly think you’ll only lose 25% of strength with a scaffold knot? I thought in a majority of ropes, the scaffold knot regularly lost about 35 -40% percent strength meaning the retention would be closer to 65% of the 5400 lbs that oplux is rated to... A figure 8 is usually one of the stronger knots and even then the loss will be between 20 and 30%. At least that’s my understanding. With oplux I think the strongest splice per say would be a Viking splice aka a sewn end termination. Typical loss with it is about 15-20%. I would definitely be curious to see how well a class 2 splice did with oplux.

 

[Fl Canopy Stalker]

To answer question #2, yes, a single test proves very little. If I get a splice to hold over 5,000 pounds, I will likely have a few more tested before I actually trust it. I will not use the standard Tachyon splice method for Oplux again as I an confident the failed splice was done according to directions--I made that splice 8 or 9 times before the test splice.

If you get 5000 lbs out of a splice on oplux you will be an instant hero to all... I’ve yet to hear of an eye making it beyond 4500 lbs for oplux and that was a sewn eye not a splice

 

[Fl Canopy Stalker]

I did a 72 diameter straight bury in RescTech that tested at 5183 lbs. using Samson’s reduction and tapering instructions for Class II single braid. I removed the inner core and reburied the length to match the core reduction, tapering at the end. From what I’ve read it is important to try to taper to a final fiber for the most strength retention. Mine broke in between the two splices, so the rope itself broke, the ends were close, might have done better with more space between them.
Below from the left is a double braid, one and only, a locked brummel and bury, the tested piece, and the splice in Oplux.
View attachment 43036
Again from what I’ve read, most knots slip, and those that don’t only test to 50% of the break strength at most, a cover does little to help.

Isn’t rescue tech like 1500 lbs higher breaking strength than oplux though? So you are only retaining about 75% for the splice as well right?

 

[Brocky]

Isn’t rescue tech like 1500 lbs higher breaking strength than oplux though? So you are only retaining about 75% for the splice as well right?

Right, the Oplux would break at a lesser strength than the RescTech.