where do I get thinner kevlar? and one other shock cord Q

[BeerorKid]

I picked up some 1/8th from Top Flight, but am looking for the thinner stuff I see used here often.

Two Amazon ones I was looking into (I am an amazon whore)

https://www.amazon.com/dp/B007HFUQFU/?tag=skimlinks_replacement-20

https://www.amazon.com/gp/product/B004GBGVYS/?tag=skimlinks_replacement-20

I so want a baddazz Defender II, and saw he was using black kevlar cord for building. I figure you all could point me in the right direction. Would rather support a smaller seller if possible.

Why do many folk use such insanely long shock cords?

 

[stealth6]

Couple things:

First, that black cord does not seem to be kevlar. It may be strong enough, but it won't have the heat/fire resistance of kevlar, which is the main point of using it. That cool looking black stuff might just melt on you, which is not a good thing.

Second, there are tons of deals to be had on thinner kevlar cord on E(vil)bay. If you shop smart there, you can get it very cheaply.

Third - why such insanely long shock cords? Well, for me it was after going too short too many times and having far too many recovery problems (mostly having my main chute deploy at apogee on dd flights). After a few good TRF folk got it through my thick skull to go LONGER!, I finally started going much longer than I had felt comfortable doing previously. No problems since. Sounds good to me.

s6

 

[pick1e]

I got some on eBay, later realized it was cheaper directly from their website (EmmaKites) which I didn't know about beforehand:

https://www.emmakites.com/Wholesale-braid-kevlar_c385

Since then I've seen KevlarGuy, a vendor (Kevlar Store) post right here on TRF in the Vendor section, they'd be a good candidate for your business I would say:

https://www.thekevlarstore.com/

Why do many folk use such insanely long shock cords?

To prevent damage from the nose cone colliding with the body, fins, etc. during the ejection process. Also some people use only Kevlar with no stretchy stuff. If you do this you need an even longer cord since Kevlar has no stretch or "give" to it. If the cord is too short, the nose cone is traveling so fast when the cord becomes taught, that the force rips the cord right out of the mount. With a longer cord, the parts can slow down much more due to the air resistance. Some people (like me) combine materials, i.e. Kevlar with some elastic or rubber. On bigger rockets people use a length of nylon strapping which absorbs some of the shock.

 

[FastCargo]

The longer the cord, the more energy it can absorb. Less chance of 'Estes dents', or zippers.

FC

 

[BeerorKid]

Awesome. Makes sense to me. I am an ebay whore as well.

One more question that might get lost in this thread.

Why do I need an E launcher for E engines? Are the ignitors different? Could I get buy with a basic 12 volt battery?

 

[BeerorKid]

Thanks so much for the tips. I will pick up some.

The long shock cord makes so much sense to me now after this weekends launches. A bit of rubber cord breaking got me my camera and rocket out of a tree.

I am really excited for the next 4 builds I have in front of me. I have learned so many cool tricks from you guys that will become part of the builds.

It is really appreciated.

 

[chadrog]

The only difference with the E launch controller is it has longer leads, offering farther distance from the pad. Yup, that's it.

 

[BeerorKid]

The only difference with the E launch controller is it has longer leads, offering farther distance from the pad. Yup, that's it.

Thanks so much for that. I just placed a decent hobbylinc order and decided against the E launcher out of principal. I could use speaker wire and launch off my truck. Now I know I will be fine. Need to pick up speaker wire anyways

Does anyone use light rubber bands on their shock cord gatherings? I guess a good wrapping would do fine as well.

 

[caveduck]

Even more info for the pile...besides the kevlarstore most of our vendors including BMS, Semroc, and Apogee have kevlar thread/cord in various sizes. I couple of weeks back I chased the supply chain a bit and found https://www.thethreadexchange.com/ which has nearly all the sizes I've seen up to 225# or so and in quantities up to 16oz spools, and also a wide array of nylon thread suitable for stitching smaller parachutes. In HPR land you'll find a lot of heavier kevlar from our community vendors too.

Looks like you're having fun, keep up the good work!!!

 

[Rex R]

e launcher; #1 the safety code specifies 30' minimum distance, you really don't want to be to close, E's and above are loud, and it is a bit easier to track your bertha when it disapears from the pad with that nice E-motor when you're standing further back.
rex

 

[chadrog]

Estes should offer an "E12" launch controller, with 300 feet of wire.

 

[Rex R]

aww they are not that bad , none of the catos I saw saturday split the case, nozzles and roman candles yes(along with the usual comments of, 'ooo cool, do it again').
rex

 

[Bubba02STi]

I picked up some 1/8th from Top Flight, but am looking for the thinner stuff I see used here often.

Two Amazon ones I was looking into (I am an amazon whore)

https://www.amazon.com/dp/B007HFUQFU/?tag=skimlinks_replacement-20

https://www.amazon.com/gp/product/B004GBGVYS/?tag=skimlinks_replacement-20

I so want a baddazz Defender II, and saw he was using black kevlar cord for building. I figure you all could point me in the right direction. Would rather support a smaller seller if possible.

Why do many folk use such insanely long shock cords?

Apogee sells 200# kevlar... fairly thin and fairly decent even on mpr... ived used it in several rockets with out a problem


Using long shock cords is a good way to let as much kenetic energy bleed off before becoming taunt after ejection... this helps save the balsanose cones from dents...

 

[pick1e]

Thanks so much for that. I just placed a decent hobbylinc order and decided against the E launcher out of principal. I could use speaker wire and launch off my truck. Now I know I will be fine. Need to pick up speaker wire anyways

It will be a surprisingly short time before you're launching composite motors. Just go ahead and start putting together a 12V launcher. :grin:

 

[Bubba02STi]

It will be a surprisingly short time before you're launching composite motors. Just go ahead and start putting together a 12V launcher. :grin:

+1 it sure didnt take me long... lol

 

[powderskierman]

Check out this guy on ebay. Great price and service. emmaxiao emmakites is the store. They have it all from 100lb to 1000lb kevlar. Sorry I couldn't post a link. Just search emmakite or kevlar kite string.

Cheers

 

[fyrwrxz]

Estes should offer an "E12" launch controller, with 300 feet of wire.

LMAO!! Sad, but true. Goggles required.