http://farm6.static.flickr.com/5007/5276737771_db9da7e38f_b.jpg
The braided sheath is very slippery and made from round section yarns. The core (eight loosely twisted and crimped cords, one is coloured as in the photo) feels warmer to the touch and consists of extremely fine round section yarns, (I needed a dissecting microscope to find this out). Diameter is 8mm. I was told that it is used by British Telecoms but had no information as to use.
Any info would be appreciated.
Ben
Most likely, the rope is made of polyethylene. The core is probably some other material, maybe a high modulus PE. You can test whether it is high modulus by stretching it. If it is impossible to elongate by stretching, it is a high modulus fibre. If it is somewhat elastic, it is not HMPE, but something else.
It is possible that it is another polymer in the polyolefin family. You can try if it floats in water; most likely it will.
Hi Ben. I have some similar looking rope and if it’s the same the outer sheath is polyethylene (usually known as polythene), the core is probably polypropylene but I can’t be certain. It is very stiff and difficult to knot being so slippery though a Zeppelin Bend and a Grinner Knot (aka a Double Fisherman’s) will hold. Someone gave it to me and I have yet to find a use for it!
Barry
Thank you for your replies, I hadn’t thought of the floating test. The sheath floats so is probably polyethelene (it just doesn’t feel like polypropylene). The core sinks, does polyester sink? I tried burning the core and it did burn but sort of ran away from the flame and went out. Is burning a test?
Ben
The inner may not be polyprop as it usually floats - if it doesn’t melt it may be a cellulose based material such as rayon which will smoulder and burn but not melt. My impression is that whatever this is designed for it’s cheap so the core is unlikely to be an expensive material such as polyester or HMPE.
Barry
The most used fibres of the polyolefin family are polyethylene and polypropylene; both float in water.
Polyester is slightly heavier than water, it sinks. Prestretched polyester has very little elasticity, while polyamide is very elastic. Non-prestretched polyester is somewhere inbetween. It is highly unlikely that it could be polyamide, it wouldn’t make sense to mix with polyethylene, as one of the preferred properties in any electric industry is that the polymer should not absorb water; one of the primary reasons for using polyethylene. Another reason for choosing polyethylene is that the fibre is very slippery, if it is to be used as a drawing line, to pull electric cables through ducts.
I have seen a similar rope being used for that type of work, where the core was hitched to the cable, and the sheath was pulled out over the junction. That kind of bend will not snag.
Burning is a test. Fleeing from the flame is typical of some cellulose based fibres, but also polypropylene has this behaviour.
I have no idea what the material is - but what on earth is the binding on the end ? ? ?
Derek
what on earth is the binding on the end ? ? ?
That is a good question, it resembles a wall knot made with two cords.It came from a video on how to make a soft shackle at http://www.colligomarine.com/. On the right hand side there is a section on “Helpful How To Videos”.
The knot they describe in their literature is a Stevedore knot
SR
Ask British Telecom … .
Re burn test : PP/PE both burn w/o support of a flame,
the former more vigorously, and maybe it is the one whose
drops can be stretched, like taffy (or is it the other way 'round?);
PA/PES (nylon/polyester) do not burn when a supporting flame
is removed; the former has white, the latter black, smoke.
(And there’s a smell test of the smoke, but that sounds dangerous.)
You say that something doesn’t feel like PP : do you realize that PP
can come in multi- (as well as the typical mono-) filament form,
in which is resembles the other multi-filament fibres, though is
coarser --a difference I’m not sure is so perceptible to fingers,
but which can be specified.
HMPE is at times said to be undie-able (no color, except in some
coating), but I’m not sure of that --I have some Spectra that’s
gray, and that seems to be its color w/o coating; I have some
Dyneema SK-75 which I think is well coated w/urethane (deep blue).
As for the structure in the orange bit,
it appears that there’s a “mobius” splice in the piece coming
anti-clockwise into the muddle,
and the rest is impossible to figure out (but there appears to be
a slightly whipped tail upper-left!?).
(Conceivably, core or sheath is composed of two types of fibres,
though mixtures of PP & PES usually (to my awareness) have mono-fil
fibres.)
As for the structure in the orange bit, it appears that there's a "mobius" splice in the piece coming anti-clockwise into the muddle,
Yes, it is not in the instructional video, I added it to make two cords into one.
there appears to be a slightly whipped tail upper-right!?).
A constrictor made from some of the core prior to fusing the two ends together.
And there's a smell test of the smoke, but that sounds dangerous.
I have read in a plastics welding article that Polyethelene smells like a candle when burning whereas polypropylene smells like burnt oil, the orange sheath on this rope does smell strongly like a candle when burning so I suppose that it is Polyethelene.
http://www.instructables.com/id/Handy/step16/Identify-Different-Types-of-Plastic/
Well I’m afraid I can’t tell you what it’s made from , but I can tell you it’s a draw rope for pulling cables into ducts. I don’t think BT use it, they mostly use Blue BT drawcord which I believe is staple spun polyprop. I’ve got several hundred yards of this orange stuff that came out of some fibre optic ductlines owned by the company I work for. The ductline is about 2" diameter and comes rolled on a drum in about 100m coils with the drawcord pre-installed. It does sink, as my Grandsons will tell you after playing with it in the marina I keep my boat in. I haven’t found a good use for it yet but it is extremely strong and doesn’t seem to stretch at all. I don’t like it much but it seems too good to throw away. I might try making some scramble nets if the hitches don’t slip. Joining or terminating it our lads tend to use the ‘Contractors splice’, which works well enough and all you need is a swedish fid and some tape. It is so slippy on the sheath because of the need to pull through the duct, I suspect there may be some lubricant on the sheath. I have some older stuff that feels dryer, and it’s a very hard fibre that gets brittle and splinters with age like polyethelene does. The core feels more like dyneema or somesuch to me. Not a lot of help I know, but that’s all I can tell you. Cool plastic ID site by the way!!
If you find a good use for it please post it as I have a long length of something similar and so far all I can think of is barrier rope (when I can find someone with a barrier!)
Barry