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I am ashamed to admit that after unboxing my first serger many years ago, I threaded it with 30-year-old unbranded thread my mom gifted me when her super old serger broke.
I was on a budget after my serger splurge purchase, and this seemed like a great option.
Well, it turns out that using old thread isn’t a stellar idea if you want to keep your machine fuzz-free and not deal with repeated thread breakage. Lesson learned!
So, what’s actually the best thread for a serger, and what types of threads will work with sergers? In short, the best thread for your serger depends on your intended use, budget, and decorative requirements.
Keep reading to learn the best serger thread types and which ones you need to start serging!
Assessing Serger Thread Quality
Not all serger threads are created equal! Choosing the best quality serger thread means you won’t have to worry about fraying, breaking, excess lint, or skipped stitches.
A good-quality thread will feel smooth with only minimal thread fibers visibly protruding out of it.
To check for quality, hold a small section of thread between your two hands, and examine it. The more short fibers, the lower quality thread, and the more lint in your machine as you serge.
Sure, you could use that hairy-looking thread (see above) in your machine, but you’ll later be doing extra lint cleanup!
Also, if your thread is not uniform in thickness, tension issues and breaking threads can ensue.
What Color Serger Thread to Use?
Purchasing the rainbow of serger thread colors is not necessary.
On interior seams, the only thread to closely match to the color of the fabric is the left needle thread. (It’s the only thread visible when a seam stretches.)
If you can’t find an exact match, choose a darker (rather than lighter) thread for that left needle. Then, choose complementary neutral colors for the right needle and looper threads.
This means for dark fabrics, use black or gray as looper threads. For light fabrics, use white or beige.
In addition to the above universally blendable colors, I also frequently use navy, red/rose, and gold thread in my loopers.
Best Serger Threads (Types Explained)
Here’s more in-depth information about the types of threads that work well with an overlock machine.
1. Serger Cone Thread
For everyday serging of knits, wovens, and everything in between, use serger thread cones.
Serger cones are economical and convenient, and good-quality options are uniform, smooth, and strong enough to withstand high overlock stitching speeds!
Commonly created from core-spun polyester and cross-wound on the cone, overlock cone threads are finer than all-purpose sewing thread, which reduces thread bulk at seams. Being cross-wound also means the thread unwinds from the top without the cone spinning–this makes for more even, smooth feeding when serging at high speed.
The intended use of serger cone thread is for general serging in the needle and looper threads.
You can use it for serging seams, creating edge finishes, and even adding decorative applications. (Variegated serging thread, like above, is fun to use!)
While polyester is the most common, you can also purchase cotton overlocker thread.
It’s strong and soft but shrinks as with all things 100% cotton, and it produces more lint due to its shorter fibers.
2. General-Purpose Thread or All-Purpose Thread
All-purpose threads are the parallel-wound spools of thread you see at your craft and big box stores.
Common fiber compositions include cotton, polyester, or cotton-covered polyester.
So, can you use sewing machine thread on a serger? Yes, sewing machine thread works on sergers and can be used for finishing fabric edges, decorative construction, and even some seams.
However, you might want to consider other options for the loopers at least.
Sewing machine thread is strong and durable, but with how much thread serger sewing machines go through, you’ll constantly be replacing your thread spools! (Rethreading a serger is NO fun.)
The great thing about all-purpose thread, though, is its variety of colors.
I use serger cone threads for the loopers and right needle and then a matching all-purpose thread for the left needle thread when sewing a seam.
My favorite types of sewing thread to use for my serger are Coats & Clark polyester thread and Gutermann thread.
3. Polyester or Rayon Embroidery Machine Thread
Embroidery machine threads are usually polyester or rayon and are known for their gorgeous luster and shine. That’s why they’re perfect for embroidery designs!
These threads are also cross-wound and work in overlock machines.
However, they’re not as strong as serger cone thread or sewing thread, so they shouldn’t be used in loopers and needles for heavy-wear garments.
However, they’re a good choice for the left needle when you can’t find a matching serger thread color.
When comparing polyester vs. rayon embroidery threads, I prefer polyester.
Polyester threads are more colorfast and stronger than rayon threads and are thus better suited to seams that will see heavier wear.
In addition to providing the matching needle thread for seam construction, embroidery machine threads provide beautiful edge finishes and decorative effects. Think of how beautiful a rolled edge or flatlock stitch with lustrous embroidery thread would be!
4. Nylon Sewing Thread
This strong thread is used for sportswear, bags, and upholstery.
It’s not a go-to thread for many serger users, though. Why?
It can lose its color and melt at very high temperatures. (Always use a press cloth when ironing and decrease the temperature.)
However, because it melts so easily, you can actually find it as nylon fusible thread, which intentionally melts to provide a temporary bond when pressed with an iron. You can read more about all its uses if interested.
5. Textured Nylon Thread (Woolly Nylon)
Woolly Nylon is the trademark name for a fluffy thread that comes in various colors.
However, other thread brands have their own versions of textured nylon thread. One example is Maxilock’s Stretch serger thread.
The hallmark of textured nylon thread is when pulled taut, it shrinks in the middle.
When relaxed, it fluffs back up, showing its good stretch and recovery. It thus spreads out well and covers seams when stitching a rolled hem or decorative ruffle finish.
You can also use textured nylon to finish edges and create seams on items that need softness like lingerie, knits, athletic wear, and swimsuits, for example.
One issue with Woolly Nylon thread is its soft, fuzzy texture makes it more difficult to thread through your serger. You may need to use a looper threader to get the thread where it needs to be.
Also, as this is nylon thread, remember to use low temperatures and a press cloth when ironing to decrease melting risk and keep the color from fading.
And lastly, while you technically could put it in all the serger threads, use textured nylon thread primarily in the loopers.
6. Monofilament Thread (Invisible Nylon Thread)
This fine, strong, transparent thread comes in clear or smoke and can be used anywhere you want “invisible stitches.”
I’m not a huge fan of monofilament thread. It tangles easily, breaks, and gets stuck everywhere.
Some brands are better than others, and I’ve found the most success sewing with Sulky Invisible Thread. There is a definite learning curve to using invisible thread, though.
7. Silk Thread
Silk thread is expensive but adds shine and a luxurious feel to projects. To save money, only use it on threads that will show.
Polyester and rayon threads are less expensive alternatives with beautiful luster.
Types of Decorative of Serger Thread
The above serging threads are more popular for serging seams and finishing edges with only some decorative applications.
Now, let’s talk about some of the best overlocker threads to use when looking to add a decorative effect to your project!
A. Metallic Thread
Metallic threads have a nylon or polyester core with metallic foil twisted around it.
They have minimal stretch but are perfect for a shiny, decorative finish. These are especially pretty when flatlocking, edge stitching, or adding any decorative effect, really!
B. Hand Embroidery Floss
Yes, I’m talking about the floss you use when hand embroidering.
Simply wind the embroidery floss onto a bobbin, thread it through your machine, and feed it through slowly as you stitch!
This can produce a beautiful rolled hem, decorative hem, or flatlocked stitch. There are many types of hand embroidery floss, so pick one that’s smooth, not too wide, and not too textured.
C. Glow-in-the-Dark Thread
Yes, you can even use glow-in-the-dark thread for decorative stitching!
It activates when exposed to light and then glows when lights go out.
D. UV Color-Changing Thread
I use color-changing thread on my embroidery machine frequently for fun, but you can also run it through your serger loopers and needles for decorative effects.
It is one color inside, and when exposed to UV light outside, it changes to a different color!
E. Serger Yarn
Serger yarn is a specialized cross-wound yarn for use in serging.
It is very thick, so it can really only be threaded in the loopers. It makes a fun decorative edging and is common in finishing edges of fleece blankets and serging sweater knits.
F. Serger Ribbon
There are a few types of ribbon made specifically for serger use.
You need to be very careful when feeding ribbon through your serger, but if you can successfully master this type of decorative serger thread, you can add fun finishes to so many projects!
Tips for Serging With Decorative Threads
If you do decide the best type of serger thread for your project is a decorative one, here are tips and tricks for serging with decorative threads like metallics.
- If your project is one-sided, only use it in the looper on the right side of the fabric. For two-sided projects, use it on both loopers.
- Decrease thread tension.
- Pick appropriate needles (for example, a metallic needle) to make sure the thread will pass through the eye.
- Check the label for care instructions regarding washing, drying, and ironing.
- Use a thread net for slippery decorative threads that fall off the spool and pool at the base.
Serger Thread Weight Explained
Thread weight refers to the thickness of the serger thread.
The higher the weight number, the thinner the thread. Generally, serger thread is 40 weight. However, you can purchase 50 weight or other weights, if needed.
Where I Purchase My Threads
While I like to purchase my serger cones from Amazon, Sewingmachinesplus.com, JOANN, and Wawak. Sometimes local sewing shops have a better variety and selection of more unusual serger threads and serger supplies.
In conclusion, the best serger thread for general use is polyester serger cone thread of good quality.
If you have different serging needs or are ready to branch out, try adding other types of serger threads to your collection!
New to serging? Check out my favorite beginner serger books!