[Walt Fricke]

With apologies to the owner of this posting, who just wanted matching belts:

Nylon loses strength due to exposure to UV. The U.S. Army's Natick labs came out with a chart showing this during WWII or therabouts. If the exposure is especially intense, the loss can be pretty quick (year or two). Climbers have learned to be careful using the nylon slings other climbers left part way up a tall cliff when they rapelled off. Without UV or mechanical damage it stays strong a long long time.

How much loss a car seat belt has endured is hard to estimate without destructive testing. I suspect stretch/elasticity decreases (weight X will stretch length Y less as strength decreases), but don't know that for sure.

But one doesn't hear of seat belts, no matter how old, failing due to loss of strength. And there are lots and lots of car crashes all the time, and nowadays most folks belt up, and there are a fair number of old cars still on the road. Someone found a report of a Canadian helicopter (or some kind of aircraft) crash into a lake where the quite old pilot's belt (shoulder harness on an inertial reel, I think) broke on impact (guy survived, if I recall). Picture showed it to be a bit ratty looking anyway, and in a high sun exposure location.

In a rational world you'd just purchase new webbing, take the hardware to the local parachute rigger, and have the sewing done.

1) I haven't been able to find, at least not easily, a source for the right webbing.

2) I have a sewing machine capable of stitching through three or four layers of webbing, and used to make my own climbing harnesses. But I have been unable to find specifications showing what the proper thread or pattern is (so I just stitched the ***** out of things, and I'm here so it must have sort of worked).

And then there is another issue. Any of you guys ever take apart one of the retractors? Well, when installing a roll cage in my car I removed mine. For some reason I decided I needed to take the web off of the reel. When I did the reel (spring loaded) sprang. I could never get it re-spring loaded like it was before and still insert the belt. I'd get almost there with screw drivers in the slot in the rod in the middle, and something would slip and bzzz, back to square 1.

As to used belts, I'd look for several things: fading is a sign of excess UV. Stiffness of the nylon I'd count as a bad sign also. And, of course, signs of abrasion, knicks, tears, cuts, whatnot. If the color is good and it is supple and undamaged, I think the odds are good it retains enough of its original strength.

And I'd want it on the reel so all I had to do was bolt things on.

Walt Fricke