The 1/8" stuff is cheap enough, therefore it is ridiculous that kit manufacturers don't include at least 4' in EVERY KIT BT-50 sized and above. BT-70 and above should have 8'. I would GLADLY pay the extra $0.50 per kit, which is what manufacturers would be paying in bulk.

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When in doubt, WHACK the GAS and DITCH the brake !!!

Yes, there is such a thing as NORMAL, if you have to ask what is "NORMAL" , you probably aren't !
Failure may not be an OPTION, but it is ALWAYS a POSSIBILITY.
ALL systems are GO for MAYHEM, CHAOS, TURMOIL, FIASCOS, and HAVOC !

I've been using 1/4" swimsuit elastic - its cotton covered and braided. It holds up to the ejection charge just fine; I haven't had to replace one yet due to melting, unlike the less durable 1/8" synthetic covered elastic. I get it from Joanne Fabric.

I've also got a bit of 1/4" elastic that was supposed to be cotton, but turned out the seller was wrong and its synthetic. Bleh...

I'd love to have cotton covered 1/8" FLAT elastic, but haven't found any yet.

And then there is the braided Kevlar cord: light, strong, fire-resistant:
https://www.amazon.com/gp/product/B...e?ie=UTF8&psc=1

Since my last rubber shock-cord failure (Quest motor powered 1:200 Sat-V), I've rekindled my distaste for rubber weak-points in shock-cord chain. One the second flight, the stock Estes rubber broke, and nose cone drifted into the next zip code. The bulk of the airframe came down ballistic, narrowly missing a parked car.

You can bet that I had gone back and 3x checked all my Low-power rockets to purge them of any remnants of nylon or stretch cords.

YMMV,
a

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Radrocketeers.org NAR & Tripoli L2