I am Going Back to Elastic. Kevlar is a tangled nightmare.

[brockrwood]

@prfesser @86mustang408w

You guys are encouraging me to spend money on Amazon.

I bought a spool of the Emma’s kites 250 pound braided kevlar line. I bought a spool of the “9KM” brand, 300 pound braided kevlar line for comparison.

The 300 pound stuff seems considerably thicker, but otherwise they seem similar.

(Again these acquisitions should last me a long time.)

I will try a length of each as shock cords in upcoming rocket builds. I will let you know how they perform, including tangling.

 

[86mustang408w]

@prfesser @86mustang408w

You guys are encouraging me to spend money on Amazon.

I bought a spool of the Emma’s kites 250 pound braided kevlar line. I bought a spool of the “9KM” brand, 300 pound braided kevlar line for comparison.

The 300 pound stuff seems considerably thicker, but otherwise they seem similar.

(Again these acquisitions should last me a long time.)

I will try a length of each as shock cords in upcoming rocket builds. I will let you know how they perform, including tangling.




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I have the same stuff! I got black this time but I usually stick with yellow to see any burns better. It works well, another thing you can do to prevent fraying after knots is put a little CA on the ends. I've been using kevlar now with many rockets for months and no issues. Be careful when you pack the wadding/dog barf and where the shock cord goes, kevkar is flame retardant not flame proof(I had an instance a few weeks back with my High-Flier XL after wadding the shock cord was right in line foe the ejection charge. Did it again and held the shock cord at the top of the body tube). It will burn thru, and lately I've been using a mix of kevlar and elastic for some to create a weak spot for tree recoveries, and just in general use. With kevlar in the body tube to the top CR or tube, and well out of it to a quicklink or the nosecone. My Partizon, Leviathan, and SBB all use the 550 pound and its perfect. And honestly it's exactly what rocketry shops sell. I needed a lot so I went to the source. Another thing to prevent tangles is chute swivels and most have a quicklink in the recovery system. But a good thing to prevent tangles is after you launch and get the rocket. Wrap the chute back up and put the nosecone in for the trip back home. I too throw all the rockets I dont put the chutes back in, into plastic bags so they all don't get tangled together.

 

[brockrwood]

I have the same stuff! I got black this time but I usually stick with yellow to see any burns better. It works well, another thing you can do to prevent fraying after knots is put a little CA on the ends. I've been using kevlar now with many rockets for months and no issues. Be careful when you pack the wadding/dog barf and where the shock cord goes, kevkar is flame retardant not flame proof(I had an instance a few weeks back with my High-Flier XL after wadding the shock cord was right in line foe the ejection charge. Did it again and held the shock cord at the top of the body tube). It will burn thru, and lately I've been using a mix of kevlar and elastic for some to create a weak spot for tree recoveries, and just in general use. With kevlar in the body tube to the top CR or tube, and well out of it to a quicklink or the nosecone. My Partizon, Leviathan, and SBB all use the 550 pound and its perfect. And honestly it's exactly what rocketry shops sell. I needed a lot so I went to the source. Another thing to prevent tangles is chute swivels and most have a quicklink in the recovery system. But a good thing to prevent tangles is after you launch and get the rocket. Wrap the chute back up and put the nosecone in for the trip back home. I too throw all the rockets I dont put the chutes back in, into plastic bags so they all don't get tangled together.

550 pound stuff? Shoot now I need to order another roll from Amazon! ;-)

 

[86mustang408w]

550 pound stuff? Shoot now I need to order another roll from Amazon! ;-)

I think I have 135, 150, 200, 250, 550, and 1800, lol.

 

[cls]

Didja buy a pair of kevlar scissors? Essential to prevent fraying.

Consider one wrap of masking tape on the kevlar at the cut line; cut it in half. That prevents fraying, too.

I rub white glue or yellow glue in the ends. But I'm sure CA works.

 

[augendoc]

Oh BTW, these kevlar-only scissors are totally worth the $$$. Makes a clean, trim cut, every time. No more frayed ends.

I can't remember, maybe got them at Joann fabrics, or perhaps Amazon (hold my nose).View attachment 603281

These scissors are designed for fiberoptic and kevlar. At least one edge is finely serrated. Speaking from experience, I can vouch that hey cut both cleanly. Here's the Amazon link: Amazon - fiberoptic/kevlar scissors

 

[brockrwood]

Didja buy a pair of kevlar scissors? Essential to prevent fraying.

Consider one wrap of masking tape on the kevlar at the cut line; cut it in half. That prevents fraying, too.

I rub white glue or yellow glue in the ends. But I'm sure CA works.

There are scissors just for cutting kevlar line?

 

[brockrwood]

Cost of LPR model rocket kit: $15. Maybe $25 or $50 for a really big one or scale model.

Cost of Supplies and Tools, including trying 4 different spools of kevlar line and the kevlar scissors: Hundreds, maybe thousands of dollars.

Sigh. I thought LPR model rocketry was a “cheap” hobby. I mean I am not lovingly restoring muscle cars of the 70’s and 80’s here. I am just gluing balsa onto paper tubes.

It’s kind of like hobby electronics: You need a $900 oscilloscope to measure the performance of a $0.10 transistor.

 

[cls]

There are scissors just for cutting kevlar line?

Yes, previous page

https://www.rocketryforum.com/threa...ar-is-a-tangled-nightmare.181990/post-2482671

(You can borrow my Tek oscilloscope and my Rigol spectrum analyzer)

 

[brockrwood]

Yes, previous page

https://www.rocketryforum.com/threa...ar-is-a-tangled-nightmare.181990/post-2482671

(You can borrow my Tek oscilloscope and my Rigol spectrum analyzer)

I have a 20 mhz analog oscillosope. An old one. BK Precision. It works amazingly well. But you do a lot of “counting” of the little grid lines to figure out frequency and amplitude.

 

[86mustang408w]

I bought a good pair of scissors from Hobby Lobby(8 bux?) and they do the trick for lines and nomex I cut. Yeah its going to get expensive, but I can tell you it's not as bad as other hobbys that I've had. You'll accumulate things like every everything else. I bought so much because I have so.many to build. And with the kevlar lines they are longer so you use more. You can use a mix of a few things. The biggest thing about going kevlar was every rocket I built 10 years ago with elastic needed to be replaced recently. Plus I've had many times when the rubber shock cord burn thru and the rocket separated, that would have not happened with kevlar.

 

[bjphoenix]

My pocket knife (another hobby) cuts the stuff very easily.

 

[86mustang408w]

My pocket knife (another hobby) cuts the stuff very easily.

Exactly, So does a hobby knife. Helps to cut it on wood, so you slice in to the wood too. It gives you a cleaner cut, then I've been putting CA on the tips.

 

[brockrwood]

Some shock cord for my LPR rockets. This won’t get tangled!

;-)

 

[SolarYellow]

I have been using E6000 for the "sizing" at the end of the kevlar lines. It stays relatively soft and flexible when dry. Also, it didn't work for what I originally bought it for, so I regard it as basically scrap, or free material. I got the four-pack of tiny tubes, having experience with that general type of glue in the past drying out and becoming useless after only a little has been used. More $ per ounce up front, but less $ per ounce when all the tubes are in the trash at the end.

 

[gldknght]

Paracord. Easy to cut, easy to untangle, easy to use. Been using it for years, both with pistons and traditional systems, no issues.

 

[cwbullet]

@prfesser @86mustang408w

You guys are encouraging me to spend money on Amazon.

If you are willing to wait. You can buy it on AliExpress.

 

[brockrwood]

If you are willing to wait. You can buy it on AliExpress.

Checked out AliExpress. Looks like a better alternative to ebay or Amazon when you want to buy stuff from the Far East (which is where most stuff is made whether we like it or not). Yes, especially if I want to “stock up” on something, I can wait a few weeks for it to get here.