kevlar thread?!

[thunderzy]

Has anyone here ever sewn with kevlar thread? Im going to attempt to repair my motorcycle racing suit. Eventually I would like to add some stingray patches to the most commonly impacted areas. If anyone is familiar with Kevlar thread let me know what you think of it? Is it difficult to work with? How strong is it? Should I be considering a different thread?

Thanks

Zack

[kevinhopkins]

Has anyone here ever sewn with kevlar thread? Im going to attempt to repair my motorcycle racing suit. Eventually I would like to add some stingray patches to the most commonly impacted areas. If anyone is familiar with Kevlar thread let me know what you think of it? Is it difficult to work with? How strong is it? Should I be considering a different thread?

Thanks

Zack

Hi Zack,

You can use kevlar, but normally it's a flat type thread, and is difficult to use on a machine. I'm sure you can buy it in machine format, but it might be difficult to find in small qtys. most folks I know, (including our shop) simply use bonded nylon for inlaying Stingray. we've never had an issue to date. And you can get bonded nylon about anyplace.

Kevin/Springfield leather

[Bree]

I have Kevlar thread and I very seldom use it. I use it when I absolutely need superior strength for structural reasons. Kevlar is very strong and kind of slippery. It doesn't hold a knot well as the knot weakens it a lot. Spectra is even worse for being slippery and hard to knot or lock down. And they are both so strong that they can slice through your fabric or even leather like a knife. For 99% of what I do, Poly or nylon are just fine.

[thunderzy]

Is poly and or bonded nylon strong enough to hold under extreme conditions? Remember this will be for my motorcycle racing leathers. I crash a decent amount, at least 3 times a year. The suit has to stay together under 40-80 mph impact and some 10-30 ft of pavement sliding.

[5shot]

I would think bonded polyester would hold up in heavier wieghts, but kevlar would surely be better. The down side (beyond what is mentioned above) is that Kevlar will destroy your machine eventually. It will act like a little hacksaw blade and cut into everything it rubs against. If you only use a bit, might take forever to happen though.

The same issue applies to fishing line of the same design. It takes special guides on the rod to keep the line from cutting through when the big brute peels off a bunch of line.

[CampbellRandall]

In my opinion, Kevlar is normally not used just for strength, but for heat resistance. Kevlar has a melting point of about 900 degrees (vs about 500 for poly/nylon). If your looking for strength, increase your thread size or sew multiple lines at the seams and you dont have to pay 6 times the price of nylon or poly. The requirements of the jacket are to hold up to heat (i.e. crash and burn) then Kevlar or Nomex is recommended.

[Bree]

Is poly and or bonded nylon strong enough to hold under extreme conditions? Remember this will be for my motorcycle racing leathers. I crash a decent amount, at least 3 times a year. The suit has to stay together under 40-80 mph impact and some 10-30 ft of pavement sliding.

Ask a main line manufactuer of racing leathers like Vanson what kind of thread they use. You are asking a very specific question with potentially serious consequences if the answer is wrong. Ask someone who assumes the liability for making a mistake every day.

Regardless of the thread, I think you want to double or triple stitch as well as glue high stress areas. Note that most racing leathers are loaded with patches. There's a reason for that and it isn't just to advertise. All those patches add a lot of abrasion resistance.

You will find poly to be a bit more resistant to abrasion than nylon. Kevlar has good abrasion resistance and I would highly recommend Kevlar cloth as reinforcement. But the thread has very little stretch and is so strong that it might act like a knife and actually cut the garment when heavily stressed. That stretchiness of poly and nylon gives it some shock absorbing capability.

Those are some random thoughts. But I would say ask someone who specializes in making these leathers. I don't.

[tonyc1]

I make a fair bit of strapping for gallopers and harness horses and I find the nylon handles wear and tear a lot better than the poly.

Tony.

[barra]

As someone who deals with Aircrew safety and survival equipment, I use a fair amount of Nomex thread and can extol it's virtues.

Characteristics remain after laundering.

Chemical resistant.

Mildew resistant.

Resistance to heat.

Abrasion resistant.

Flame-resistant. (does not melt or drip but chars at about 700F)

Barra

[tonyc1]

Where do you buy Nomex from, Barra?

Tony.

[barra]

Nomex is made by DuPont. I'll look up where we get it from in Australia tomorrow.

Barra

[Bree]

Unless you have to have fire resistant thread it's going to be tough to justify $63 per 8 oz versus $9 per 8 oz for #69 bonded thread Nomex vs Nylon or Poly. You lose a lot of breaking strength going to Nomex as well... probably about 40%. Quite frankly if fire resistance AND strength are needed, Kevlar is a better choice methinks since it costs about the same as Nomex. OTOH... once again, Kevlar is so strong that it might be TOO strong.

My $.02

[thunderzy]

Wow!! thanks everybody!

[5shot]

I make a fair bit of strapping for gallopers and harness horses and I find the nylon handles wear and tear a lot better than the poly.

Tony.

Interesting - I use nylon for my holsters, but hear lots of Internet Experts who talk about the superiority of Poly. Good info!

[kenny]

Interesting discussion, i was thinking of using kevlar thread but i've decided not to worry about it after reading this. Nylon seems to be hard to get in different colors so i was going to go with polyester. What would you all recommended nylon or poly?

Also what is a good size thread to use for bike leathers/jackets etc? I had some 20 but it seemed a bit big, i noticed Bree mentioned #69 is that the size you're referring to there Bree?

[Bree]

Interesting discussion, i was thinking of using kevlar thread but i've decided not to worry about it after reading this. Nylon seems to be hard to get in different colors so i was going to go with polyester. What would you all recommended nylon or poly?

Also what is a good size thread to use for bike leathers/jackets etc? I had some 20 but it seemed a bit big, i noticed Bree mentioned #69 is that the size you're referring to there Bree?

If I were going to be sewing biker leathers, I would use poly. It has a bit more UV resistance. I would use size 69 thread. It is pretty much the standard. It is .01" in diameter and has 10 or 11 pounds of tensile strength depending on the manufacture. It's good stuff.

Nylon would also work. The strength is similar but it likes UV less than poly. And biker jackets are exposed to UV and under stress. I often sew patches on with nylon because they are not stressed members of the garment but for seamwork I usually switch to poly. I keep both on hand.

[kenny]

Thanks a lot Bree that's a great help especially for a novice like me! Yep i think the 69 will be good especially for sewing lettering and those fiddly little bits.

I may try nylon but im only just starting so im trying to keep it simple

[BondoBobCustomSaddles]

Is poly and or bonded nylon strong enough to hold under extreme conditions? Remember this will be for my motorcycle racing leathers. I crash a decent amount, at least 3 times a year. The suit has to stay together under 40-80 mph impact and some 10-30 ft of pavement sliding.

OK Thunder! On a side note, I have raced most every thing that can be pitted against something else, however; ( and I am surprised no body chimed in on this) if I was getting dumped that much, I think I would be looking for something else to race I did a pavement slide once @ over 80mph many years ago, it happened and was over so quick that the slide itself didn't hurt, but; afterward was a real awakening!!

Bondo Bob