Cord/small gauge rope that doesn't deteriorate in the sun?

May 29, 2005 3:24 PM

Is there some way to get rope or cording which won't fall apart after a summer in the hot southern Arizona sun? Last year I installed some roll down window shades made of bamboo to take the brunt of the sun that was otherwise streaming in the windows. These aren't the most well constructed shades ever invented, but they did admirably at providing a cheap solution to shading my windows from the intensely hot summer.

All except for one thing. The cords that you use to pull up and down the shades are completely disintegrated. Almost all of them have snapped off and those that haven't are looking like they'll fall apart if someone breathes on them. Like I said, these are cheap window shades and the sun around here is HOT.

I think I can replace them, but my question is this: Is there a cord I could replace these with that wouldn't need replacing every year? Maybe a UV resistant one? Or would something like hemp be a less likely to fall apart after a summer filled with 100+ degree temps?

posted by mulkey to Home & Garden (13 answers total)

Anything you put on your windows in the hot So. AZ sun is going to suffer from decomposition or what I call 'sun rot'. The window coverings I had for my windows with the most sun were vertical blinds that had insulation woven in them. they were not inexpensive. What a lot of people do is put the film on their windows that takes some of the burn out of the sun.

I am afraid any inexpensive solution will need replacing. Remember, the temperature coming directly from the sun in the desert is way higher than what they tell you on the local weather report.
LAG
posted by lag at 4:05 PM on May 29, 2005

I was also thinking monofilament. You can get it woven in small ropes and also get the kind that has UV resistance. I haven't tried it for this purpose specifically, but I would guess that since it's made to stay outside for long periods of time, it might work.
posted by jessamyn at 4:58 PM on May 29, 2005

Mulkey, I just shopped for rope at the local hardware store yesterday. They had a handy chart showing the pros/cons of different materials. I can't remember all the categories, but the general summary goes something like this:

Synthetic fibers, such as those found in the cords for most blinds/shades, have two significant drawbacks: they deteriorate in sunlight and they stretch under stress. (The latter may or may not be a negative depending on your application.)

Natural fibers have two significant drawbacks: they rot when wet and they do not stretch under stress. (The latter may or may not be a negative depending on your application.)

In general, synthetic fibers are stronger than natural fibers.

That's all I remember. (And I may have some of my facts wrong, but I think that's generally correct.)

I don't know how if this helps for your quest for the perfect pullcord. My recommendation would be to hunt on-line for (as you suggested) a hemp-based cord, or something from jute, or some other natural fiber.
posted by jdroth at 5:03 PM on May 29, 2005

I would think that Vectran-based yacht cordage would have the most UV resistance - try Layline.
posted by nicwolff at 5:14 PM on May 29, 2005

You could try Spectra cord. It has "High resistance to chemicals, water, and ultraviolet light." It's ultra-high-molecular-weight polyethylene.
posted by Kirth Gerson at 5:45 PM on May 29, 2005

Visit your local army navy surplus. It'll have an entire aisle of cords, ropes and lines of every sort.
posted by boo_radley at 7:07 PM on May 29, 2005

i just got some of these cheap outdoor blinds..I'm thinking of installing them backwards if possible. mainly because I'll have to lean out my second floor window to close it, but that would keep the cord out of the sun...
posted by jacobsee at 7:33 PM on May 29, 2005

Nylon breaks down under exposure to UV rays. I recommend cotton thread or string. When I worked at a company that made convertible tops, we made sure we didn't use nylon thread on exposed surfaces because it greatly increased waranty repairs. It literally disintegrates in the sun. (If you think about it, virtually anything made from nylon from outdoor chairs to tents eventually break down after exposure to sunlight.) From this website (go to second last paragraph), "Nylons are sensitive to ultraviolet (UV) radiation. Weatherability will be reduced unless UV stabilizers are incorporated into the formulation. Carbon black is the most commonly used UV stabilizer. Carbon black lowers the ductility and toughness as a trade-off for UV stability."
posted by Doohickie at 8:29 PM on May 29, 2005

I have used cord made specifally for blinds to good effect for this purpose (I assume that the blinds are on the inside of the windows). I think is is called, surprisingly;-), Venetian Blind Cord.
posted by dg at 9:18 PM on May 29, 2005

For the extreme: Wire rope. You can get it down to 0.1 mm which is about as flexible as many cord and in stainless is practically indestructible in your application.
posted by Mitheral at 9:53 PM on May 29, 2005

The dark grey cord that duck hunters use to string decoys is the right size I think, very UV resistant.Available at outfitter type places. I use it for desert camping, rigging shade tarps.Knots easily, and is hard to break. not exotic or expensive.
posted by hortense at 10:04 PM on May 29, 2005

I tried to find venetian-blind cord in hardware stores here, without much luck. The closest I could find was chalk-line cord at Home Depot. It's slightly thinner than the original cord, but works. Don't know if it (or venetian-blind cord) is in any way UV resistant.
posted by Kirth Gerson at 4:23 AM on May 30, 2005

I think the chalk-line cord is made from cotton or other natural fiber; should be okay in UV.
posted by Doohickie at 7:36 AM on May 31, 2005