Lifespan of cotton thread

regius

Active Member
This must have been spoken about in various topics but couldn't find one dedicated thread. I recently experienced the vintage cotton stitching falling apart issue on my motorcycle jacket by Excelled, it's only from the 50s, leather is in prestine conditin, but the seams are coming apart (well, let me elaborate, they are together, but about one inch of stitching disappeared, and as I slowed opened from there, the cotton threads easily break, resulting me opening the whole sleeve). In contrast, some 50s jacket, say the Windward that uses "nylon" thread as they say on the label, nylon or poly, I don't know, but the metallic shine of the thread definitely says not 100% cotton, stay together no issue, and even when trying to cut, it's feelably strong.
So,WW2 A2 all used cotton, but there are original specimen people wear. So, I guess it depends on the quality of the thread? and by 100% cotton (like Bill Kelso, GW, ELC), they do mean 100% cotton, no polyester at all?
I do suppose these repro A2 will hold up for say at least two decades?
 

33-1729

Well-Known Member
The cotton thread ought to last, like the cotton lining. Degradation of the cotton thread may be due to a leather conditioner being used, such as mink oil, rather than normal wear and tear. Vasoline is a safe leather conditioner that won't degrade cotton threads. Use sparingly.
 
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regius

Active Member
Thanks! What's in mink oil that a lot of people stay away from? it's just fat, like the Japanese Redman horse fat, Leatherique restore, and leather milk etc etc, or Montana pine pitch (plant lipid). Is it because the "Mink Oil" commercial product contains silicone?
 

Geeboo

Well-Known Member
Think it in another way. The sewing machine plays a very important role of how a seam will hold. Say a professional brother sewing machine, simple straight stitch, will hold way much better than in the mall, US$20 machine. The tension, the under thread, the stitch count - there are a lot of knowledge in sewing itself - which I don't know the details but all attribute to how well a seam holds. That is the value of a machinest - in Ken's of of Aero terms. Some factories use the best machine [suitable for the job] while others use mediocre machines which had resulted in a less durable seam. It cannot be told from the outside - both are just "seams" - not until you tried to un-do the seam you know the tension of the sewing - some are really really strong U can tell upon un-stitching the seam up.
P.S. in terms of thread, as with leather, the thicker the gauge the stronger the thread - which last longer- other things being equal
 
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Juanito

Well-Known Member
The cotton thread ought to last, like the cotton lining. Degradation of the cotton thread may be due to a leather conditioner being used, such as mink oil, rather than normal wear and tear. Vasoline is a safe leather conditioner that won't degrade cotton threads.
This^^^^^^^.
 

foster

Well-Known Member
There are a lot of factors that influence how well cotton thread will last. My educational background and career is in textiles, and apart from what has already been mentioned here are just a few factors that can impact the life span of the cotton:

Storage conditions. Cotton can get dry-rot due to bad storage, and the molecular structure of the cellulose breaks down. The fibers basically crumble and break.

Oil exposure. This has already been mentioned to a degree, but when cotton absorbs oil it can lubricate the fibers causing them to lose the friction from fiber to fiber which holds the thread together. Cotton absorbs moisture / water and will swell and become stronger when wet. Oil interferes with the ability to absorb moisture, which can over time also result in fiber degradation depending on the type of oil.

Abrasion. Exposed fibers that protrude above the fabric or leather surface are exposed to more wear, and when abraded away the stitches lose their hold.

Leather tanning. If the leather hide was not tanned within certain parameters, there could be residual corrosive chromium salts or a different pH that could impact the material surrounding the thread, and can affect the thread over time.

Human sweat. I have some friends who know they have some aggressive perspiration that rots certain fibers if the clothing is not washed or laundered to remove it. Leather jackets are not usually laundered. This is an extreme case that does not affect most individuals.

Geeboo makes good points about the sewing machines used. One can also consider the method of spinning and twisting the yarn to also be a factor. Sewing thread is usually twisted more than the yarn used in fabric, as some of this is eased out of the thread in the sewing process. But if the sewing thread was overtwisted too much in the beginning, this also results in a weaker thread regardless of other outside factors.

Dye color. The dyeing process can weaken fibers. Some fibers are dyed numerous times and it was common practice in the industry to take excess production of various colors and dye them black in a subsequent process. If the cotton was dyed repeatedly, and is a black color, this could also contribute over time to weaker thread.
 

B-Man2

Well-Known Member
There are a lot of factors that influence how well cotton thread will last. My educational background and career is in textiles, and apart from what has already been mentioned here are just a few factors that can impact the life span of the cotton:

Storage conditions. Cotton can get dry-rot due to bad storage, and the molecular structure of the cellulose breaks down. The fibers basically crumble and break.

Oil exposure. This has already been mentioned to a degree, but when cotton absorbs oil it can lubricate the fibers causing them to lose the friction from fiber to fiber which holds the thread together. Cotton absorbs moisture / water and will swell and become stronger when wet. Oil interferes with the ability to absorb moisture, which can over time also result in fiber degradation depending on the type of oil.

Abrasion. Exposed fibers that protrude above the fabric or leather surface are exposed to more wear, and when abraded away the stitches lose their hold.

Leather tanning. If the leather hide was not tanned within certain parameters, there could be residual corrosive chromium salts or a different pH that could impact the material surrounding the thread, and can affect the thread over time.

Human sweat. I have some friends who know they have some aggressive perspiration that rots certain fibers if the clothing is not washed or laundered to remove it. Leather jackets are not usually laundered. This is an extreme case that does not affect most individuals.

Geeboo makes good points about the sewing machines used. One can also consider the method of spinning and twisting the yarn to also be a factor. Sewing thread is usually twisted more than the yarn used in fabric, as some of this is eased out of the thread in the sewing process. But if the sewing thread was overtwisted too much in the beginning, this also results in a weaker thread regardless of other outside factors.

Dye color. The dyeing process can weaken fibers. Some fibers are dyed numerous times and it was common practice in the industry to take excess production of various colors and dye them black in a subsequent process. If the cotton was dyed repeatedly, and is a black color, this could also contribute over time to weaker thread.
Good post ... very enlightening... thank you
 

Nnatalie

Active Member
Dye color. The dyeing process can weaken fibers. Some fibers are dyed numerous times and it was common practice in the industry to take excess production of various colors and dye them black in a subsequent process. If the cotton was dyed repeatedly, and is a black color, this could also contribute over time to weaker thread.
That is quite interesting! I have a bunch of spools of vintage cotton thread (probably 1940s-60s, but could be earlier or later), and while most of it has survived just fine, a few were easily breakable with my hands. It might just be a coincidence, but I think the weak ones were all black.
 
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