How do I seal Kevlar shock cord edges?

[tibbe]

I got a Kevlar shock cord from Apogee Components. The edges aren't sealed in any way so I'm worried they will fray. How can I seal the edges to prevent that? Melting them won't work and I hear epoxy (and CA?) makes the Kevlar brittle.

 

[dhbarr]

If by edges you mean ends, I use flexible medical tape.

 

[kevinkal]

I've had good results "sealing" the cut ends using Titebond II wood glue. I simply dab the glue on the end of the Kevlar, and work it into the fibers at the tip, making sure not the squeeze all the glue out. Then I form the tip into the shape I want it to cure into, then let it dry. Works great for me.

 

[K'Tesh]

 

[dmgrime]

I use heat shrink tubing around my knots (usually a Duncan knot) and cover the loose end back over the main line.

Example in this post:


https://www.rocketryforum.com/showthread.php?t=130936

Sent from my SM-G920V using Rocketry Forum mobile app

 

[dr wogz]

I hear epoxy (and CA?) makes the Kevlar brittle.

Yes and no. Yes, it will make the Kevlar brittle, but only where you've applied the glue. The glue will bond & harden the fibers, and, at the point between them being glued (stiff) and unglued (not stiff) is where you'll get your weak point and eventual (possible) failure. if you're tying a knot in the cord, the free end, (the 'tag' end) will never have any stress on it, and so, putting a drop of CA on it won't affect it's overall strength (over the length of the cord).

And, I usually just tie an over-hand or figure-8 knot to stop the cord form fraying / unravelling..

 

[hcmbanjo]

CA glues will run up the Kevlar line and make it brittle.
You could use a small drop of epoxy on the end, that won't fun up the line as far.

I usually use Titebond, smearing a drop around 1/4" at the end.
After it dries the frayed end is hardened and can be cut clean with wire cutters.

Wire cutters will cut better than a hobby knife and you won't end up with a dull knife blade.
Kevlar is used in the place of steel wire in many applications, why not cut it like wire?

 

[farsidius]

I use either shrink tubing or just masking tape. But mostly masking tape. It'll start to wear after ~10 flights, but just wrap it again with some more. It's very heat resistant! I also wrap masking tape around ~2 feet of the kevlar cord that connects closest to your ejection charges - just extra protection for your recovery system.

-brant

 

[ksaves2]

A dollop of CA at the very end of the cut end of the Kevlar isn't going to hurt a thing and will keep it from unraveling. Do not, I repeat, do not saturate a knot with CA. Makes the Kevlar brittle. The flexible Titebond or shrink tubing are much better remedies to
hold a know. Kurt