Best way to glue nylon stap

I looking for the best way to attach nylon strap to a quick link. In the past I just was able to epoxy the nylon to itself. Is this the best way? Thanks,

Reply to
lovs2fly
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I fold the strap in half lengthwise for about 3" then loop it through the quick link then wrap it with kevlar thread tightly and finally a coat of 5 min epoxy. Never had a failure.

btw, I got this tip from Giant Leap.

Ted Novak TRA#5512 IEAS#75

lovs2fly wrote:

Reply to
nedtovak

Dennis-

If it's tublar nylon, Robert DeHate has a good way on his web site.

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He shows it using Kevlar but it should work with tubular nylon too. Some people sew or glue the part that's inside to the outside. I'm not sure if that helps or not.

Good luck Phil

Reply to
Phil Stein

If you can't sew a loop in the end of the strap, a good strong knot should still be much much better than attempting to glue it.

It's generally a bad idea to apply adhesives to ropes, cords, straps, webbing, and other string-like things. The edges of the adhesive joints provide weak spots, as the fibers are unable to shift to accomodate tension changes. You'll find that the weakest point is almost always adjacent to such a joint.

If it were me, I'd use a bowline or similar knot to secure the strap to the quicklink.

- Rick "No glue threads, please!" Dickinson

Reply to
Rick Dickinson

This should be in the FAQ.

Reply to
Jerry Irvine

At least it is the rare and elusive tech post from you.

Reply to
Jerry Irvine

That method "works", but in an ultimate stress failure situation (late ejection) it might fail as a result.

Reply to
Jerry Irvine

I've tried the "DeHate" method on tubular nylon, and it dosen't work. The nylon is too slick, and the loop just slips out. Works excellent on kevlar, but not TN.

Sewing the ends into loops is the best way to attach nylon to a quick link.

Reply to
J.A. Michel

I understand it's a bitch to sew. Someone I know that had it done went to a sail maker IIRC. Guess a shoemaker could do it too. Also, PML has a reccomened method that I've used. Only problem with it is that it uses a lot of cord. I can't find a picture of it on their web site.

Reply to
Phil Stein

What Robert shows is called "finger trapping", and it's how the navy does cables and riggers do man-rated lines.

The trick with either TK or TN is to then run it through the sewing machine afterwards, to keep it from pulling out -- without tension, the loops can (and will!) slip, even in TK.

I've got a rigger buddy who does that to all of my TK for me.

-Kevin

Reply to
Kevin Trojanowski

I sew a loop into the end, using nylon thread, before applying epoxy. Haven't had one fail yet... :-)

Reply to
Len Lekx

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I don't think a properly tied bowline has ever let me down. Perhaps the most useful knot ever devised.

Reply to
NaCl

Reply to
J.A. Michel

I don't know if it's the "best" way, but the method I use to put loops on nylon strapping and/or tubular nylon is the technique described in the August 1999 issue of HPR Magazine, on page 41.

It involves making a loop in the nylon, wrapping the folded-over part with many wraps of nylon thread or twine, soaking the twine and nylon at that point with CA, and coating the CA'd twine wrap with epoxy.

Your mileage may vary, but for me it works great, and it's never given way, even when used to recover large, 100+ lb. rockets, or when involved in accidental, high-speed deployments.

...Rick

Reply to
Rick Dunseith

As a "used to be a caver" sort, I've used and destroyed a lot of tubular nylon. A few general things I'd offer about the stuff.

Don't use adhesives directly on the nylon. Some are benign, some are not. Better to avoid them all. Similarly, don't write on nylon webbing (especially using a 'sharpie' type permanent marker). 6-6 nylon is damaged a fairly wide range of substances, and any webbing that has been exposed to acids (even fairly mild ones), strong bases, or any petroleum products should be considered compromised.

Age also affects nylon. Properly stored, it's been discovered to lose 5% of it's strength in the first year, and about 3% a year after that, leveling off at about 50% of the original rated strength. "Properly stored" simply means away from light and any chemicals. Exposure to light seriously accelerates the process, and can leave you with a piece no stroger than used toilet tissue. A piece of webbing from the bottom of your old climbing kit might not be the best choice.

Sewing is probably the most compact method of attachment. A heavy duty sewing machine with a good ball needle (for bluejeans, for example) is adequate to sew two layers of webbing. Don't try three... I've gotten yelled at for breaking the machine trying to do so. For more layers or heavier threads (thus fewer stitches) a hand sewing awl is the trick. Easy to use once you get the hang of it. Either method can create a bond as strong or stronger than the webbing itself (depends on the number of stitches). I would not recommend using kevlar thread to sew the webbing... I suspect it would cut the nylon fibers under load.

Knots are also useful. To create a loop, double the webbing back on itself, and tie a single overhand knot in the webbing, as close to the loop end as possible (leave at least a 2" loop in 1" webbing, 1 1/4" in 9/16" webbing). Be sure there are no twists in the webbing. Leave a tail on the knot of at least 3"-- sewing this will improve the "neatness" factor.

1" tubular nylon, as found in most stores, has a rated breaking strength of 4400 lbs static load. Sewing a loop reduces the strength of the webbing by about 10%, tying a knot by about 35-50% (depends on how well the knot is dressed). Any time you create a loaded bend in the webbing you reduce it's strength.

The most likely fail point in a webbing system will be at the point of the tightest radius bend... in most cases over the metal attachment devices. Using a ferrule of some sort, or the largest radius connector you can find, will reduce the likelihood of failure at that point. The dynamic (shock) load is going to be the real problem. Webbing is made for static loads, and has no stretch to speak of (less the 1/2%). Almost all the load placed on the webbing will be transmitted to the junction between anchors and nylon. The skinnier the anchor, the more likely it will cut through the webbing. Also, if the webbing is "bunched" in the bend it's strength is further reduced as the load is placed on only part of the webbing. Using attachment points wide enough to support the full width of the webbing flat would be better than, for example, a screw eye.

I suspect that at some point, repeated exposure to ejection gasses could have a deleterious effect on the nylon as well, both because of heat and the composition of the gases themselves. If the nylon is stiff, glazed, or cracked at the surface, it's time to consider replacing the stuff. I've seen pre-sewn webbing runners with nomex or kevlar covering the first 4' or so... these seem like an excellent idea.

Kevin OClassen NAR 13578

Reply to
Kevin OClassen

Doesn't CA damage nylon? I think someone said that here recently.

Reply to
Phil Stein

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