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

I fly pretty much all low power, and I make my own chutes, usually cut an octagon out of store shopping bags (the Hobby Lobby and Target ones work really well, Walmart bags are a bit thin.) Fold in half, fold in half again, fold in half again (1/2, then 1/4, then 1/8), then cut. Use a hole punch backed with piece of cardboard to punch the a hole in middle edge before I unfold-- so all your attachment points are equally distributed. Use paper reinforcement rings (kind you would use to reinforce paper on a 3 ring binder) around the holes. Always attach the cords to a snap swivel.

My problem is finding a good string. I have tried Kevlar thread, at least what I have is too stiff. Kite string unravels too easy. Anybody got any good ideas? Doesn't have to be flame-proof (pretty much if it is hot enough to melt my string the plastic chute is already toast.) Needs to be moderately strong, very flexible/scrunch-able, and ties without unraveling.

thanks,

Tom

Same here, I pretty much raid the recycle bin for some of the more colorful bags to make into LPR chutes (for 13, 18, 24 mm rockets up to D power)

I use a heavy duty cotton thread for carpet or upholstery, or "button & craft," you can find this at typical craft stores with a fabric goods section. I think they have some specialty polyester threads for outdoor upholstery which would be suitable too.

I use a 50 lb braided fishing line you can get at Wally World. Right now I have this weird brand, but they're pretty much all the same. It's dark green and comes off the spool a little stiff, but you can easily relax it with your fingers with a swipe or 2. This stuff doesn't fry as easily as upholstery thread or kite cord and I have yet to see it break.

Gary Byrum said:

I use a 50 lb braided fishing line you can get at Wally World. Right now I have this weird brand, but they're pretty much all the same. It's dark green and comes off the spool a little stiff, but you can easily relax it with your fingers with a swipe or 2. This stuff doesn't fry as easily as upholstery thread or kite cord and I have yet to see it break.

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Based on the one chute that Gary made for me, I would have to endorse that stuff. Looks weird but feels nice and seems quite strong.

Gary Byrum said:

I use a 50 lb braided fishing line you can get at Wally World. Right now I have this weird brand, but they're pretty much all the same. It's dark green and comes off the spool a little stiff, but you can easily relax it with your fingers with a swipe or 2. This stuff doesn't fry as easily as upholstery thread or kite cord and I have yet to see it break.

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+1 for braided fishing line.. and you might want to use 20lb test.. 50lbs might be a bit much! but is thicker. I once had a spool of pretty thick thread. some heavy stuff for buttons & coat hems. some sewing threads will have their strength printed on them..

My I also suggest Mylar for your chutes, not plastic. Shiny / metallic wrapping paper.. space blankets.. light, shiny (good visibility) "space age"..

neil_w said:

Based on the one chute that Gary made for me, I would have to endorse that stuff. Looks weird but feels nice and seems quite strong.

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I am wondering how that chute is holding up. I now make them with small grommets in the corners for added strength. That sewing method wasn't quite where I wanted to go with making them. I like the new concept better. The grommets are no bigger than a standard pencil eraser.

Gary Byrum said:

I am wondering how that chute is holding up. I now make them with small grommets in the corners for added strength. That sewing method wasn't quite where I wanted to go with making them. I like the new concept better. The grommets are no bigger than a standard pencil eraser.

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It's holding up fine after 1 flight.

I don't expect the APRO II to be a frequent flier, so this won't be the most stressed-out chute in the world. But I'll keep an eye on it.

dr wogz said:

My I also suggest Mylar for your chutes, not plastic. Shiny / metallic wrapping paper.. space blankets.. light, shiny (good visibility) "space age"..

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I like the durability and shininess of Mylar. For my BT50 and smaller rockets though it seems a bit stiff, even when I crinkle the heck out of it.

Polyethylene of 1/3 to 1/2 mil thickness work great, if you can find the stuff that hasn't been modified for anti-suffocation. You can color it with black magic marker if it's clear. I still have a supply of red cleaner bags from way back when. For shroud lines I use nylon rod-winding thread (got last batch from Bass Pro), attached with U-Line mylar tape. No reinforcement/grommet needed at the attachment points; the mylar tape is a great reinforcement itself and is ultra thin. These days a lot of the poly has been modified; you have to test by trying to put a crease in it. If it takes a crease, it's no good and will not deploy. Modern dropcloth plastic is no good despite tempting specs and wide rolls.

1/4 mil mylar is also great, but a little stiffer. For competition I can get an 18-20" mylar chute to deploy out of a BT-5, but not much more without using a longer tube. Same shroud lines and attachment. 1/4 mil mylar is now hard to find - at the moment Andy at ASP is the only vendor I can think of that carries it. 1/2 mil mylar is much easier to get and works great for heavier models up to several ounces, but needs a larger tube and heavier model. If packed tightly into a small tube on a light rocket it won't deploy, especially if it's chilly.

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.

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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I think I will try this, found it on Amazon for decent price.
Will also try some braided fishing line.
Thanks folks
I will get back with results
Tom

caveduck said:

... I still have a supply of red cleaner bags from way back when. ...

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So do I. Bought a roll of red cleaner bag material from a supplier 40 years ago. Must have been 1000 feet - gave most away. Was amazed that I found it the other day - about 30 feet left.

Atwood rope micro and nano cord are great for DIY chutes. Both are braided. Micro is 1.18mm/100lb and nano is .75mm/36lb. I use both. Great stuff at a good price.

https://atwoodrope.com/collections/micro-cord
https://atwoodrope.com/collections/nano-cord

sl98 said:

Atwood rope micro and nano cord are great for DIY chutes. Both are braided. Micro is 1.18mm/100lb and nano is .75mm/36lb. I use both. Great stuff at a good price.

https://atwoodrope.com/collections/micro-cord
https://atwoodrope.com/collections/nano-cord

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Looks promising. Colors are a nice touch.

Does it unravel easily? That’s the problem I am having with my kite string.
Is it flexible? That’s the problem I am having with Kevlar thread.


Saved the site on my IPad, will consider it after trying out above.
Thanks!

It is braided so it doesn't unravel. Also flexible.

Yellow is nano and multi color is micro

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I just finished a Mini Max, and thought that the body tube is plenty big enough to fit a 9.5" chute instead of the streamer. I found an image of the larger 18" chute and traced it to fit on a chute cut from the blank back side of a Target shopping bag with a Permanent Sharpie. Kind of rough sketching here, but enough to get the idea.

GlenP said:

I just finished a Mini Max, and .....

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Nicely done sir

Tom:
I've been using 13lb 2-strand Kevlar thread for years on chutes from 3" to 48" competition 1/4mil Mylar chutes and most Custom Thin plastic sport chutes for about the last 15years. The thread I'm using comes from Micor-Mark on a 600yd spool and costs about 20.00 per spool.

I've found the only trick to using this very thin and flexable thread is to tie an overhand knot about 1/2" from the ends of the shrouds and create a horseshoe loop under the tape disc. This knot and half loop prevent the line from dislodgging even under High Load openings. below is a pic of the spool and how I attach the shrouds to the canopies. Hope this helps.

PS: by using kevlar it has eliminated all shroud line burn offs from my sport and compeitition chutes.

Micromeister said:

Tom:
I've been using 13lb 2-strand Kevlar thread for years on chutes from 3" to 48" competition 1/4mil Mylar chutes and most Custom Thin plastic sport chutes for about the last 15years. The thread I'm using comes from Micor-Mark on a 600yd spool and costs about 20.00 per spool.

I've found the only trick to using this very thin and flexable thread is to tie an overhand knot about 1/2" from the ends of the shrouds and create a horseshoe loop under the tape disc. This knot and half loop prevent the line from dislodgging even under High Load openings. below is a pic of the spool and how I attach the shrouds to the canopies. Hope this helps.

PS: by using kevlar it has eliminated all shroud line burn offs from my sport and compeitition chutes.

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John
I looked online under Micor-Mark, Micro-Mark, and MicroMark and I am not finding 13 lb Kevlar.

Thread Exchange has this at 14 lbs
https://www.thethreadexchange.com/m...een=CTGY&Category_Code=Kevlar_Thread_Size_046

I bought some stufff from them before (I can’t remember exactly what it was called) and it was a single fiber. Thin, dry strong, but very STIFF. It does burn through when used as a shock cord eventually if it is attached to motor mount.

do you know of any other sources for stuff you use? It sounds perfect.

Thanks,

Tom

Okay, update. I found what I got in my email folder

Kevlar - Size 92 - Bonded - Monocord - 6 Oz Spool

Good stuff, but as I mentioned very stiff.

Sorry: Just checked both of my sources. neither are showing the 13lb two strand Kevlar thread anymore...so Sad!
the unbonded 2-strand is much more flexible then the bonded monocord. it actually gets softer the more it is flexed.
the other source was Edmund Scientific (www.scientificsonline.com) but the old stock number V34-863 is no longer valid.

Hey John, Superior threads has tex 40, 60, 80 spun (not bonded) Kevlar thread here: https://www.superiorthreads.com/thread/kevlar
Strength is quoted as 5-6 lb for the 40/60. Any chance this is more or less a match for the old Micro-Mark stuff? One spool would be a lifetime LPR supply for a whole club.

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.

Try some #10 100% cotton embroidery thread. It's strong, soft and won't melt like some polyester blend thread.
You can pick up a big roll at Hobby Lobby or Michael's.

I have it on good authority that a vendor used to use Coats & Clark Dual Duty Plus® Button & Carpet Thread for their LPR shroud lines... After a few changes with the vendor in question, I suspect that they still do.

K'Tesh said:

I have it on good authority that a vendor used to use Coats & Clark Dual Duty Plus® Button & Carpet Thread for their LPR shroud lines... After a few changes with the vendor in question, I suspect that they still do.

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Like this?

https://jonrocket.com/store/products/dual-duty-plus-button-and-craft-thread/cat-9_23

kuririn said:

Like this?

https://jonrocket.com/store/products/dual-duty-plus-button-and-craft-thread/cat-9_23

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That wasn't the vendor that I had talked to, but it does serve as confirmation as to the use of that brand of thread being used for shroud lines.

Why not use 50 lb Kevlar (0.015 dia thread). It meets your criteria of:

BABAR said:

Needs to be moderately strong, very flexible/scrunch-able, and ties without unraveling.

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Kevlar is good for 800 F.
Nylon / Polyester 458 F.

more data here... https://www.thethreadexchange.com/m...=CTGY&Category_Code=kevlar-thread-information[/quote][/QUOTE]

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

GlenP said:

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

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