What colour shock-cord resists ultraviolet the longest?

[dancrane]

I fitted oversize 10mm shock-cord as a spinnaker-pole lift about 18 months ago. I don't think I looked at it last year and I can't visit, now.

I also fitted black 6mm shock-cord, and elsewhere closer to home, some pricey black braid-on-braid. I've noticed lately that the black braid looks decidedly old and tired after about eight months.

I've no idea how well the cover protects the rubber core of shock-cord, or what the cover is made of, or whether braided polyester is more vulnerable to UV.

Has anybody noticed that one colour (or grade or type, or manufacturer) lasts better than others?

 

[GHA]

Got this from ebay but can't comment on UV stability just yet. Here's hoping..
NEON YELLOW BUNGEE CORD bungy elastic rope shock highly durable UV stable | eBay

 

[NotBirdseye]

The cover should protect the core pretty well. UV tends not to penetrate that far unless the cord is stretched and the weave has gaps at that point it might as well not have protection. As for the color it's not the color it's the quality of the material that maters and plastic (polyester) is far more vulnerable to UV. Your best advice is to put a thick cover over whatever has been tied down to protect everything form sun damage.

 

[dancrane]

...put a thick cover over whatever has been tied down to protect everything form sun damage.

That's what I had in mind, thank you. But I was hoping to find long-lasting shock-cord to hold that cover in position.

I'll give GHA's UV-stable selection a try.

 

[Saltram31]

I use polyester tubular webbing to protect the shockcord from uv. Slip it over the cord and bunch it up, to allow for its stretch limit then use stainless steel shockcord clips to fasten it at the ends.

 

[Saltram31]

As for the color it's not the color it's the quality of the material that maters and plastic (polyester) is far more vulnerable to UV.

Polyester has the most resistance to uv damage. Polypropylene and nylon have no resistance.

 

[NotBirdseye]

Polyester is known for its strength, durability, and low shrinkage and stretch and is the most common thread for outdoor applications. Over nylon threads, polyester thread has superior resistance to UV rays and moisture but much of its strength is lost after prolonged exposure to sunlight.

Sailrite - Fabric, Canvas, and Sewing Machines Since 1969

Just for clarity here.

 

[Frogmogman]

Generally speaking, in terms of colour alone, blue is the most UV resistant - hence why a photograph left in sunlight fades to a cyan blue image over time.

 

[dancrane]

I use polyester tubular webbing to protect the shockcord from uv.

Nice smart solution - but I don't think I ever saw or heard of such a product. Where do you find it?

 

[Saltram31]

Nice smart solution - but I don't think I ever saw or heard of such a product. Where do you find it?

I bought it on ebay. Probably available from a few suppliers though.
Webbing Polyester UV resistant.White 4 sizes, 650-3000 kg breaking load | eBay

 

[dancrane]

Thanks Skatt, although I've used webbing like that, many times. I was wondering about the tubular webbing.

Actually I only had to Google it to find it for sale - although I haven't found a pic yet of the stuff that shows it to be anything but ordinary flat webbing.

But it's so cheap it's worth a punt. Likely to be handy for lots of jobs aboard.

 

[gregcope]

I recently got some of this 25mm webbing - it is internal dia is around 13mm

 

[dancrane]

Sounds very useful. I could encase lines like the topping lift, which stay out in the sun and rain all year.

 

[elton]

White absorbs the least light of all colours; that's why it looks white. Though silver reflects visible light better than anything. Black absorbs the most light of all colours, and that's why it looks black. Matt black is best of all. Don't they teach this sort of thing in school these days? Plastics have additives that make them stable, and plastic without the additives will quickly disintegrate outside. I was once a QC inspector in a plastics factory (Wavin Plastics) , where one of the products was land drainage pipe. It didn't have the normal UV stabilisation additives, because it was specifically meant to be buried. It couldn't be stored outside, otherwise within a few weeks it would become discoloured and very brittle, to the point it would shatter into tiny fragments quite easily.

 

[Quandary]

I have used underground (orange) upvc pipe a few times and specified it more often than I could ever count, one of the most popular brands was 'Wavin' though Martin Plastics were local and probably more popular. We knew it had a lower uv resistance but never experienced anything like the rapid degradation you refer to. Some parts of the system like gulleys and rodding eyes were partly exposed and seemed to survive quite well. The external vent stack on the house extension we put up 12 years ago is underground pipe because we had over ordered, it was painted though and so far has survived intact, just been out and given it a thump.

To get back to the OPs question, The lighter the better, our boat cover is held down by a selection pack of cheap Lidl shockcords in a multiple range of colours, the yellow and light green have survived the winter and are still almost usable, the purple and red have long gone, and we have not had much actual sunshine since they went on in October.