Low Power parachute shroud lines--- best string/thread

GlenP said:

This has been a really informative "thread" on this topic.

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C’mon, stop stringing us along.

I hope ThirstyBarbarian sticks his head in here... He always keeps us in stitches...

If not... I'm sew over this.

BABAR said:

C’mon, stop stringing us along.

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Sorry to keep stringing you along but here goes:

https://www.thethreadexchange.com/m...TjcKZ6q9pnkC89WIVf4B_NKUZlpNYHUYaAkHlEALw_wcB

Not too expensive, depending on your cost point.

Klatuso said:

Sorry to keep stringing you along but here goes:

https://www.thethreadexchange.com/m...TjcKZ6q9pnkC89WIVf4B_NKUZlpNYHUYaAkHlEALw_wcB

Not too expensive, depending on your cost point.

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Trying to find one like der MicroMeister described. It was braided and apparently soft and flexible.

Surprised I didn't think of this sooner, since my wife has tons of it hidden somewhere. Beading line. It has to be small, tough, and flexible. It says it's braided, it looks and feels like Kevlar.

The good news is that you should be able to find it at any craft/beading store. The bad is that calling anything 'beading' really jacks the price.

Wow! Not Kevlar. Hold a match to it and it evaporates like smoke in the wind. Flame ran up it so fast it might be a reasonable alternative for fuse. I thought it might set off the whole spool.

Leaving this here so no one else is tempted to try it.

Edit: That's funny, I just noticed it's called 'Fireline' and the color is 'smoke'.

vcp said:

Surprised I didn't think of this sooner, since my wife has tons of it hidden somewhere. Beading line. It has to be small, tough, and flexible. It says it's braided, it looks and feels like Kevlar.

The good news is that you should be able to find it at any craft/beading store. The bad is that calling anything 'beading' really jacks the price.

Wow! Not Kevlar. Hold a match to it and it evaporates like smoke in the wind. Flame ran up it so fast it might be a reasonable alternative for fuse. I thought it might set off the whole spool.

Leaving this here so no one else is tempted to try it.

Edit: That's funny, I just noticed it's called 'Fireline' and the color is 'smoke'.
View attachment 357629

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VCP You are so right! Most of the newer Fishing lines are Spectra Microbraids which are all very heat sensitive. I've tried SpiderWire, ProBraid, and several Burkley brands with the same Instant Poof results.

I did a little more digging looking for the 2-strand Kevlar thread. here's what I came up with. Scientifics Direct no longer carries the spools DEEEEEEERATS!
however www.thethreadexchange.com has two products that should do the job. I'm not sure if the 6lb is one or two strands but the 14lb has been told to me to be 2-strand.
1: Kevlar Size 23 (tex 21) .006" dia. 6lb test Natural yellow #Kev023natloob 1/2oz spool = 780yds @ 11.00
2: Kevlar Size 46 (tex 40) .008" dia. 14lb test Natural yellow #Kev046natloob 1/2oz spool = 312yds @ 8.00

Since I haven't seen these threads other then the websites photos I can't say for sure if these threads are or will be as soft as the 13lb stuff I have but both above are more than sufficient for LPR rocket chutes. I'd use the 6lb for chutes up to 30inches and the 14lb for larger. also the 6lb stuff looks like it should get softer as it is used.
Hope this helps a little.

Micromeister said:

VCP You are so right! Most of the newer Fishing lines are Spectra Microbraids which are all very heat sensitive. I've tried SpiderWire, ProBraid, and several Burkley brands with the same Instant Poof results.

I did a little more digging looking for the 2-strand Kevlar thread. here's what I came up with. Scientifics Direct no longer carries the spools DEEEEEEERATS!
however www.thethreadexchange.com has two products that should do the job. I'm not sure if the 6lb is one or two strands but the 14lb has been told to me to be 2-strand.
1: Kevlar Size 23 (tex 21) .006" dia. 6lb test Natural yellow #Kev023natloob 1/2oz spool = 780yds @ 11.00
2: Kevlar Size 46 (tex 40) .008" dia. 14lb test Natural yellow #Kev046natloob 1/2oz spool = 312yds @ 8.00

Since I haven't seen these threads other then the websites photos I can't say for sure if these threads are or will be as soft as the 13lb stuff I have but both above are more than sufficient for LPR rocket chutes. I'd use the 6lb for chutes up to 30inches and the 14lb for larger. also the 6lb stuff looks like it should get softer as it is used.
Hope this helps a little.

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Thanks John. I have followed some other suggestions and gotten the cotton embroidery thread (looks like what Odd’l Rockets sends with their kits) and it looks like good stuff.

Also got some braided fishing line and it looks strong and flexible.

Obviously neither is flameproof.

So I I’ll try the Kevlar from thread exchange too. Maybe best of all worlds.

Was thinkin’ a bit, though. For plastic parachutes (either from vendors or made of garbage bags or shopping bags) if you don’t have good wadding or baffle or piston, doesn’t matter how good the shroud line are, if the flame gets up there your chute is a wadded up ball of singed plastic. The SHOCK cord is another matter, especially if mounted on the engine mount. I have seen you have used wire fishing leaders as well as Kevlar on some of your posts.

Has anyone ever done NAR report on “how far” the torch effect of the black powder motor ejection charge extends up the body tube? Put another way, How long would the wire fishing leader need to extend forward of the front of the motor casing so there was no significant effect on the attached non metal shock cord?

Estes got away with the elastic partly by attaching it on the front end with the trifold mount. I have always hated those because I think the inside of the tube where the laundry goes should be as smooth as the proverbial baby’s behind. Plus even if you mounted it forward, you still need to make sure you had enough wadding to keep it from dropping down right in front of the motor casing.

Anyway, I’ll order some of the braided Kevlar. Thanks!
Tom

vcp said:

Is this the same stuff? SUPER-TEX-40-CRAQ-SPUN-KEVLAR-SEWING-THREAD-1-000-YARD
Maybe only a lifetime supply for a single family.

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So I got a spool of the stuff I mentioned earlier. Seems very strong; looks thinner than the button thread next to it. Very soft and flexible. It is definitely heat resistant; it won't hold a flame and it takes much more heat than the button thread before it chars.

GlenP said:

I found the spool that I have been using recently, actually a blend of 75% polyester, 25% cotton, Coats and Clark, Button & Craft, Dual Duty Plus, several colors are available. If you are using a plastic bag chute, that would melt long before this thread would burn, still have to use appropriate wadding.

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This is what Estes used in the "good old days" and what I have used for thousands of parachutes (personal and kits that I made for school use).

Klatuso said:

Sorry to keep stringing you along but here goes:

https://www.thethreadexchange.com/m...TjcKZ6q9pnkC89WIVf4B_NKUZlpNYHUYaAkHlEALw_wcB

Not too expensive, depending on your cost point.

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Here's another good shroud line thread at a reasonable price:

https://www.amazon.com/gp/product/B07K3ND8CT/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1

Steve Vise said:

Here's another good shroud line thread at a reasonable price:

https://www.amazon.com/gp/product/B07K3ND8CT/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1

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100% Polyester melts FAST.

Use the cotton covered Polyester button & carpet thread.

The THREAD is active again... OK.

One of the things to think about with the thin lines, is how likely it is to cut its way through the parachute material under a shock load. If it's going to cut itself free, it's not going to do very well.

Why not use kevlar thread?

John Taylor said:

Why not use kevlar thread?

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You can (and there are good recommendations above), but you need to consider:

Cost.

Stiffness.

If too thin, it will slice through the parachute material, the tape disc or other attachment reinforcement, etc.

It loves to untie itself wherever you tired to tie a knot.

Cost.

Availability.

Cotton covered polyester button & carpet thread is readily available at Wal-Mart, JoAnn's, Hobby Lobby, etc. and it works for most normal Model Rockets.

Yeah, I didn't read far enough back before I posted. My bad. I already have a bunch of kevlar thread so I thought of it.

John Taylor said:

Yeah, I didn't read far enough back before I posted. My bad. I already have a bunch of kevlar thread so I thought of it.

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multistrand Kevlar thread works out well, although it is probably overkill for plastic parachutes. Anything that would burn through cotton thread would likely melt a plastic chute anyway.
Single strand Kevlar thread in my opinion ends up being a little bit stiff, the multistrand seems nice and flexible.

It does tend to unravel. I've read that you should NOT use CA on Kevlar thread as it makes it brittle. I put a bit of yellow glue on my knots, that helps keep unraveling to a minimum.

shreadvector said:

100% Polyester melts FAST.

Use the cotton covered Polyester button & carpet thread.

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I am ashamed to report, that not only were you right, this particular "40 Weight" thread is NOT a 40 weight thread - in reality, it is "NUMBER 40" thread. "40 weight thread" is very thick - whereas "NUMBER 40" thread is very thin and worthless. So, perhaps by accident, they used false advertizing to sell this stuff.

Hobby Lobby, Button and Carpet Thread, $0.99. STRONG, You ain't gonna break it. Everything else will be destroyed before this stuff breaks. (I wonder if there is any debate on it being breakable to save the rocket?) Pretty thin too, not too stiff, not too limp either.