Modern high performance threads

[medion]

Hi all,

Does anyone have any input on what could be considered the strongest modern machine sewable thread for leather? I currently use a bonded nylon #69 thread which is fine, but I do wonder what the strongest machine sewable thread may be, I'm thinking in terms of Kevlar and Dyneema (or others?) - does anyone have experience with high tech threads? I understand there comes a point where the thread is significantly stronger than the leather, however I'm wanting to avoid that part of the discussion.

-p

[brmax]

Im not aware of the strength ratings of kevlar or any other in that “ super thread “.

I can say they have made most to the standard of others strength. This being regulated on standard size threads. 

Although though better durubility has came from advances in the industry. Especially towards heat and liquid environents. 

Its always good to hear what you find out, so appreciate hearing what is out there. It is important to hear these strengths based around other standards to start. Thanks

 

Good day

Floyd

[SARK9]

The Thread Exchange has info on most of this stuff-

 

https://www.thethreadexchange.com/downloads/the-thread-exchange_Kevlar_guide.pdf

https://www.thethreadexchange.com/miva/merchant.mvc?Screen=CTGY&Store_Code=TTE&Category_Code=ptfe-fiberglass-Thread-Information

Some of my research for my own applications indicates that Kevlar materials are not particularly suitable for prolonged UV exposure, and there are cases where its own relative strength is reported to be a disadvantage, as it is so much more durable than the materials it interfaces with that it can "saw" its way thru joined items in certain conditions of load stress and movement. Your designs need to take several factors into account when you wish to take full advantage of the remarkable strength of these aramid materials.

 

-DC

 

[gottaknow]

Bonded nylon is specified for the vast majority of tactical items for the DOD. A company I used to work for had a contract for suede welding jackets. Chrome tanned leather with Kevlar thread. The Kevlar thread isn’t bonded and it’s like sewing with dental floss. Your hooks have to be sharp and set very precise or it will fray while sewing. A buddy of mine that has been making hot air balloons since the 70’s uses UV rated bonded polyester which is about the nicest thread I’ve ever used. Strong like bonded nylon, but with a much softer hand. Sews like a dream. 

Regards, Eric 

[kgg]

I have to agree with Eric on the polyester thread. It is much nicer to use, not as stiff, comes off the spool more evenly as well as nicer bobbin winding / unwinding particularly as it nears the end. I use thread sizes #69, #92 and occasionally #138 depending on the dog related item. I have found that Coats bonded polyester #69 is standing up better to bleach then the #69 bonded nylon does. Example would be our incontinence pads 27" x 50" ( takes two to cover bottom of our 4' x 4'-6" HDPE whelping box). Constructed with waterproof ripstop, muslin, absorbent middle and ripstop binding on edges were washed / dried once a day in a heavy bleach concentration for 8 weeks straight. The result was no fraying or thread failures on any of the 24 incontinence pads unlike nylon thread the only problem was some colour fading of the ripstop.

kgg

[Matt S]

@medion, is there any particular reason that you're using v69 thread? Unless you have a very particular reason for using exotic thread you will probably find that using a thicker nylon, polyester or linen thread will give you more strength than you need. V69, for instance, is something I only use on light duty items like pocket notebooks and wallet internals.

If you want the "strongest" machine sewable thread I'd say it depends on what you mean by strongest. If it's breaking strain it may well be the TKT3 (about v600) bonded nylon I've recently come across. It's about 1mm diameter.

 

[SheltathaLore]

Interesting - the stiffness/springiness of bonded nylon has frustrated me a lot when I attempt to sew with it on some machines, so if bonded polyester is a solid alternative, I might have to stock up on some.

The bonus is that Serafil has tons of colors, plus a color card that I intend to squirrel away in my swatchbook stash.

[SARK9]

4 hours ago, gottaknow said:

 [...] The Kevlar thread isn’t bonded and it’s like sewing with dental floss.

 

Like he said. The lack of bonding on most Kevlar threads is a bit of a hassle when threading your needle.... First, its often very difficult to cut cleanly and tends to *puff out* with nearly invisible straggler filaments when the cut end is even slightly touched. Miss the eye on your first stab and you usually have to re-trim the frayed end. Also, you won't be melting or burning the ends of your thread tails. Color selection is pretty skimpy, and the colorfastness is a bit of a gamble with different brands. Mostly you need to find something to like about its natural yellowish color. I have used a little on nearly every machine I have at one time or another, from T-45 to T-210, and other than the hassle threading the needles, its never seemed to be that fussy to sew with any of my hooks set normally, but then, I don't really sew production quantities, just specific sporadic needs. You probably don't want to wrap a big birds nest all around and under your hook....

-DC  

[JazzBass]

I remember seeing a demonstration somewhere, that showed how strong Kevlar is in tension- it will hold an amazing amount of weight, BUT - tie a simple overhand knot, and it breaks fairly easily. I have no idea how it would function with either a lock stitch (machine) or saddle stitch. Seems that there could be problems. Has anyone else seen that demo? I can't seem to find it, or I would have linked it.

Even soft body armor has a limited service life, as the Kevlar threads seem to suffer from abrasion against each other over time, and ends up fraying.

Not sure that info helps - but I just thought I'd throw it in the mix as something to consider.

[medion]

13 hours ago, Matt S said:

Quote

@medion, is there any particular reason that you're using v69 thread? Unless you have a very particular reason for using exotic thread you will probably find that using a thicker nylon, polyester or linen thread will give you more strength than you need. V69, for instance, is something I only use on light duty items like pocket notebooks and wallet internals

The honest truth, is that I like working with unusual and high performance materials... There is no reason other than that

I do currently use v69 right throughout my wallets though, it has held up well so far - what are you using for your main wallet stitch line if only using v69 for wallet internals?

 

The honest truth, is that I like working with unusual and high performance materials... There is no reason other than that

I do currently use v69 right throughout my wallets though, it has held up well so far - what are you using for your main wallet stitch line if only using v69 for wallet internals?

[Constabulary]

The best synthetic thread I have used sofar is AMAN SERFIL / Synton (same thread AFAIK just renamed once) it runs so smoooth through any of my machines, love it! Other than that I like Gruschwitz GETAFIL P very much (I´m using 11/4 of this therad) - hellufa strong thread. I have not much use for such a strong thread however - it´s great!

GRUSCHWITZ has some "technical threads" you might be interested in but I don´t know who supplies it / if it is supplied in the US.

https://www.gruschwitz.com/en/products/standard-products.html

[Matt S]

4 hours ago, medion said:

 

The honest truth, is that I like working with unusual and high performance materials... There is no reason other than that

I do currently use v69 right throughout my wallets though, it has held up well so far - what are you using for your main wallet stitch line if only using v69 for wallet internals?

Fair enough. I've considered trying out some Kevlar or Nomex threads but I haven't seen any real-world advantages outside of a few niches like welders' gear. The limited colour and size ranges readily available in the UK, along with the technical issues associated with them (see above posts from more experienced leatherworkers than I) have made me realise that these threads are exotic for a reason.

I use v138 (TKT20) bonded nylon in my wallets wherever I can. I use a lot of this -- for dress belts, dog collars and leads/leashes, smaller bags, all the usual stuff. Usually Coats Nylbond as it's good stuff, readily available in about 20 colours, at a reasonable cost.

Like Constabulary I've used Serafil in the past, and been impressed. It's a very easy to use thread, partly because it's polyester and partly because it's not bonded. Only minor snag (literally) is that it's unbonded, which slightly increases the chance of it catching on something. However the advantage is that it opens up slightly once sewn, which makes it look a little bigger than it is -- a bit like the yellow thread they use for topsewing on jeans. I don't use it much because it's 3 or more times more expensive than Nylbond and not so easily available.

[DonInReno]

I ran across a case of Dyneema T150 that was mismarked as Kevlar and bought a spool to see how it sewed and whatnot.  That started a pretty good afternoon reading up on super threads to see just who is actually using them and what the advantages are if any.   There is a lot of misinformation with people simply repeating something they thought was credible, or misinterpreting some specification, or who knows what.  I was surprised that Kevlar simply isn’t used in many high strength applications, which essentially left Dyneema, which is essentially identical to spectra.  

The best information came from a couple of reliable places - the heavy rigging industry which uses Dyneema ropes and straps, rock climbing industry which uses Dyneema in some load-rated straps, and the riggers making skydiving harnesses.

Essentially the destructive tests done by all three industries showed negligible improvement in seam strength because the dyneema fibers cut into the non-dyneema fabric and/or webbing.  It seems the best place for Dyneema thread is with Dyneema fabric and webbing.

There is also the issue with the slickness of Dyneema - locking in the beginning and end of a seam. 

Boat people like Dyneema because the ropes are compact, resistant to cuts, strong and float.

The rock climbing folks were excited when Dyneema came on the market with claims of abrasion resistance and high UV resistance, because some climbing hardware is attached semi permanently to some climbing routes.  Destructive pull tests by a major equipment manufacturer showed the Dyneema straps exposed alongside Nylon and Polyester straps did no better retaining strength than the Nylon, and far worse than Polyester.  Dyneema company literature currently states Dyneema is highly UV resistant only if it’s ordered with a UV coating applied during manufacturing.

There was one thing worth the price of admission - I did come away with a new appreciation for the randomness of strength numbers published by manufacturers.  If we were all to vote on the breaking strength of 138 weight bonded nylon we’d essentially repeat what we’ve read - somewhere between 20 and 25 lbs.  A fresh spool from The Sewing Exchange breaks at 35 lbs on my scale.  It’s not a certified scale, but it wouldn’t be off by more than a pound.  I’m guessing manufacturers down rate thread strength for some reason, but it’s not the actual breaking strength. Kevlar breaking strengths are so all over the board it’s essentially a useless number - from no better than nylon to twice as strong!

On the same scale the T150 Dyneema broke at about 45 lbs - not nearly as much as I expected.  It sews fine on my machines without adjustment. It will dull normal scissors - definitely abrasion resistant!  Braided Spectra is available in just about every good fishing store if anyone just has to try it.  

Im disappointed there wasn’t as much information on Kevlar.

Edit: If you’re interested in just how slick and hard to knot Dyneema is just look at any big game fishing board and the great lengths they go to just to get a knot to hold.

Edited November 28, 2018 by DonInReno

[R8R]

Then there is the crazy trick where you use nylon and just add extra stitches...

[Gregg From Keystone Sewing]

This is a very good thread (no pun intended) to discuss, ahem, thread.  

The 'sewability' of thread depends on many things, and like gottaknow said Kevlar can present issues.

Kevlar can be used also for it's resistance to heat, maybe not mentioned here.  

Also, like many 'threads', one thing that is often overlooked is the amount of elasticity that the thread has.  Poly and Nylon have great elasticity compared to say a Kevlar thread.  This really presented itself when Tenara started to hype improvements of greater elasticity, after people were switching over to MR needles to get this stuff to sew without many skipped stitches.  MR needles present their own problems with the greater pronounced scarf of the needle.

Often, that elasticity is critical to the design of a sewn products, think of a sail boat spinnaker sewn with a zig zag.  This thread's ability to stretch is critical for applications like this and is figured into the construction.    

[R8R]

My experience (outside of sewing) is that nylon tends to have slightly better elasticity whereas polyester has lower elongation in general - it can be stretched and "broken in" and does not lose tension after.

Example - in screen printing, polyester monofilament mesh is the most common used woven mesh material as it can be tensioned, work-hardened and re-tensioned so as to produce a dimensionally stable stencil. Nylon on the other hand is used when some elasticity and flexibility is desired, such as for printing 3D objects and irregular surfaces, such as containers and bottles.

Another example is most modern drum heads are made of polyester film (1 or 2 ply). This makes for a head that can be tuned to a pitch, broken in, and will maintain it's pitch. Nylon films would be a nightmare! Kevlar mesh is also used, laminated with polyester films for some heads that are under high tension, such as for drum corps use.

Just my $0.02