Understanding Bonded Nylon and Bonded Polyester Thread

[Trouthunter]

I am trying to get a better understanding the differences between Bonded Nylon and Bonded Polyester.  I have #92 Bonded Polyester that seems to have some stiffness to it and some #138 Bonded Nylon and it seems to be very soft and frays easily.  Besides the size and physical makeup of the two threads.   Why is one stiff and the other soft?  Is that how it is suppose to be?  Is there a #138 that has some stiffness to it?  Seems to work better in the sewing machine.

Thank you in advance for your help.

[kgg]

It depends on what is designed for. The main manufacturers have different types of thread made for specific sewing purposes. On the bottom of your spool it will have a manufactures name, thread size, colour, weight of spool, type and brand name.

Example would be say: Coates, V69, Black, 1 lb, Bonded Polyester, Dabond

You then can go to the manufacturers website to figure out all the specs on the brand (Dabond) and what the thread was designed to do best.

If it is a generic unlabelled, typically Chinese, thread best of luck. I have see it as stiff as a board and as weak as domestic general purpose V46 and labelled V92.

Colour also makes a difference to the stiffness particularly in black as it is a result of the dying process.

The best thing to do is by a quality brand like American Elfird (made in Canada and USA) or Coates for the purpose you are sewing. You will spend a little more but the quality will always be there. There is nothing more frustrating then a bad spool of thread.

kgg

Edited December 27, 2020 by kgg
Forgot to add and speaking error

[Kcstott]

I only use nylon thread from Leather machine co. I have two small spools of polyester in a size 69. and when I bought my class 26 is came with a brand new spool of brown that was Tandy. The LMC thread is soft and supple. the Tandy thread is more like wire. stiff, abrasive, and course. 

I think it just has to do with how it's made. How many yarns per strand and how many strands per thread and how tight was it spun.  

[DonInReno]

The main difference between nylon and polyester has to do with UV resistance and strength.   Nylon is a little bit stronger, but doesn’t hold up in direct sun. 
 

 

[JJN]

Nylon will stretch where polyester will not.

[DonInReno]

This is another good source of thread and information:

https://www.thethreadexchange.com/miva/merchant.mvc?Screen=CTGY&Category_Code=industrial-thread
 

 

[CowboyBob]

We've found on thicker leather do to nylon being stiffer than poly it sews better with less skip stitches.The poly doesn't make a good loop for the needle to catch.

[Handstitched]

I use Coats thread 277 M10

Heres a bit of info: https://www.coats.com/en/Products/Threads-and-Yarns/Dabond/Dabond

Also , ' Serafil' M40 , industrial strength,  nice and soft, but a good range of colours from my supplier, and goes through domestics. And M40, also industrial strength,  from another company that supplies ' Ultimo' threads, but sometimes out of stock of the basic colours **

Both threads are polyester, the Serafil is soft, but the Ultimo is stiff. I use them on horse rug repairs, but also wallets  bags etc. 

** it pays to have more than on supplier . 

@kgg My Mother uses thread from China on her domestic machine, its rubbish.  I've been getting her to use my M40's . Well at least  the cursing & swearing has reduced    

HS

[kgg]

20 minutes ago, Handstitched said:

My Mother uses thread from China on her domestic machine, its rubbish.

Like the old adage, you get what you pay for.

8 hours ago, DonInReno said:

Nylon is a little bit stronger, but doesn’t hold up in direct sun. 

My experience is if the thread is going to be exposed to a lot of bleach, as in washing, and drying the bonded polyester thread will hold up much better.

kgg

[DonInReno]

There’s nothing wrong stocking up on as many colors and sizes of good quality thread, two spools of each of course, but you can quickly have more money in thread than the cost of your first machine.  
 

A few years back I took the chance in ordering a bunch of thread directly from Hong Kong in a variety of commonly used colors in both 92 and 138.   The sale price including shipping was so inexpensive, about $2.50 for a quarter pound spool, my expectations were low - maybe this was reject thread, or a scam, or it’s so old it wouldn’t smoothly come off the spool, or it’s mislabeled, etc.  It turned out to be good quality and worth the incredibly long shipping.  I wouldn’t recommend this for professional sewers since it could be hit or mis, but in this one case it turned out to be money well spent.

 

[nylonRigging]

On 12/26/2020 at 8:29 PM, JJN said:

Nylon will stretch where polyester will not.

Poly. thread does stretch, it just that Nylon thread stretches more than Poly. 

like ( DoninReno ) saying, the general 'rule of thumb' is that Poly.thread tends to be more UV resistant and hold dye color better when getting a beating by UV . Nylon is better for holding up for abrasion and a little higher tensile strength over Poly.

Nylon and Poly. thread both start melt right around the same Temp. , When burning each they also smell totally different . When melting thread tails,  the Nylon thread melt a lot nicer than Poly thread . I like the way Nylon thread tails makes a nice little puddle. Poly. thread tends to just Flame-on pretty intense and quick .
You also notice when hot knifing/cutting Nylon thread weave of webbing's and nylon fabrics, that it's a lot cleaner/nicer melt with Nylon.
.

[Trouthunter]

Thank you for all the guidance and help!!!

[Synicsel]

The stiffness and softness you're experiencing can be due to their individual properties. Bonded Nylon tends to be softer and more pliable, which can make it prone to fraying. Bonded Polyester, on the other hand, is usually stiffer and more durable.

[nylonRigging]

13 hours ago, Synicsel said:

The stiffness and softness you're experiencing can be due to their individual properties. Bonded Nylon tends to be softer and more pliable, which can make it prone to fraying. Bonded Polyester, on the other hand, is usually stiffer and more durable.

Nylon is structurally stronger and more abrasive resistant than Poly . Poly is more UV resistant than Nylon .  Both Nylon and Poly have there versions of ' satin soft ' threads.

.

[Synicsel]

On 1/17/2024 at 12:24 PM, Synicsel said:

The stiffness and softness you're experiencing can be due to their individual properties. Bonded Nylon tends to be softer and more pliable, which can make it prone to fraying. Bonded Polyester, on the other hand, is usually stiffer and more durable.

It's not unusual to prefer one over the other for specific projects. If you're looking for a stiffer #138 thread, you might want to check if there's a Bonded Polyester variant that suits your needs.

If you're ever interested in exploring something else, I recently came across some interesting info about Polyethylene Terephthalate (PET). It's all about plastics and recycling, which is quite a hot topic nowadays.

Edited January 18 by Synicsel