Successfully Sew with Fine 80-100wt Threads

Have you ever heard about 80 and 100wt thread? These ultra-fine threads are totally game changers when it comes to piecing, appliqué, quilting, and even as a bobbin thread. However, since most sewing machines are calibrated for medium weight thread, such as a 40 or 50wt, sometimes you may need to make some minor adjustments to your machine when sewing with this thread.

You probably won’t need to follow everything on our list to sew with 80 and 100wt thread. Most of the time these threads will sew beautifully without any trouble. However not all sewing machines are made alike, so what may work on one machine will need a setting adjustment on another. This is a list of suggestions and what issues can come up when sewing with 80 and 100wt thread, so you can sew with beautiful results.

Let’s take a closer look at these 80 and 100wt threads in comparison to a regular 50wt thread. You can see that they’re much finer, however WonderFil manufactures these threads from a cottonized polyester. This means the threads are strong and have the stretch removed from them, making them as easy to sew with as cotton thread does in the machine. They also take on more of a matte finish so they hide in the fabric a lot better.

We always recommend a needle size of 70/10 or 80/12 when working with these threads. A bigger needle will punch a hole that’s too large for the thread, so the thread will be sitting in a hole that’s too large for it to fill, resulting in an ugly stitch. The thread will also move around more in the larger eye, so a smaller eye will give you more control of the thread.

Choose a needle depending on the technique you’ll be using, or the fabric choice. For most general sewing, a universal needle works just fine. If you’re quilting, opt for a quilting needle. Or if you’re sewing with fusibles, choose a super non-stick needle, as these needles will help the thread glide through the sticky material and reduce friction.

You won’t normally need to adjust your tension with these threads and can often leave your machine on its regular tension settings. However, if you find that your bobbin thread is pulling to the top, that means you’ll need to loosen your top tension. If your top thread is pulling to the bottom, it means the bottom tension is too tight. Always sew a test piece on a scrap piece before sewing on your actual project.

Using a needle that’s too large for the thread will result in ugly holes that the thread won’t fill.

If your bobbin thread is pulling through to the top, you’ll need to loosen the top tension. If the top thread is pulling through to the bottom, you’ll need to loosen the bobbin tension.

Consider your bobbin thread when sewing with super fine threads. We recommend DecoBob™, an 80wt cottonized polyester, as your ideal bobbin thread, due to the fact that it greatly reduces tension problems and helps seams lay flatter since the thread doesn’t take up a lot of space. While we recommend DecoBob in the bobbin with any top thread, this is especially important if you’re using a super fine thread in the top. Using a much thicker thread in the bobbin can lead to bulky seams, tension problems, and a poor stitch quality.

There are some instances where it’s okay to use 100wt both in the top and bobbin. This is InvisaFil™, a 100wt cottonized polyester thread, and it’s just a little finer than DecoBob. Because it’s thinner, it won’t be quite as strong as DecoBob, but that’s okay if you’re stitching something decorative like a machine embroidery design. For anything that will require more utility, for example free motion quilting using InvisaFil™ in the top, then we suggest using DecoBob™ in the bobbin since your quilting will hold up better.

When winding these threads on a bobbin, try to go slower if you can. Because these threads are so fine and light, they tend to fly away a little and can cause tension issues when sewing. If you can, choose bobbins that come pre-wound with DecoBob™. These are available in standard sizes class 15, size L, and size M. They always come perfectly wound at the factory and fit more thread than when you wind a bobbin yourself, so you’ll have the benefit of a long-lasting bobbin that always has perfectly consistent tension.

If you are sewing anything with a single stitch, we recommend using a single stitch plate on your machine. Single stitch plates have just one little hole in the middle and is not made for any side to side stitching. This will give you more control over your thread because it will only be directed through this hole.

Single stitch plate.

Side-to-side stitching plate.

A thread plate made for decorative stitches, or any side to side stitching, will allow the thread to move around more, so the backside of your stitching can sometimes turn out not looking as nice. This can be true for any thread but is more noticeable with finer threads. This is especially important if you’re doing machine embroidery because of the speed it moves at. Single stitch plates don’t always come with a machine but can be purchased separately. These are just as easy to change and replace as a needle.

When setting the stitch length on your machine, the number displayed is in units of millimeters. So, if your stitch length is set at 2, it means you’ll have a 2 millimeter stitch length. When working with these super fine threads, we recommend you drop the stitch length down to 1.8, especially if you’re doing foundation paper piecing. Because the thread is smaller, a shorter stitch length will help a great deal for making strong, firm stitches. You’ll notice the difference with foundation paper piecing as pulling the paper out won’t distort your stitching as much as it would if you had a regular stitch length.

DecoBob™ and InvisaFil™ both come on cross-wound spools. Cross-wound refers to the direction the thread is wound in, in this case you can see they are wound around the spool at an angle. Cross-wound threads should always go on your machine on the horizontal spool pin as the thread draws best as it is pulled from the direction at the top of the spool.

If you were to put a cross-wound spool on your vertical spool pin, you can see the thread now draws from the side of the spool. But because the thread is cross-wound, it creates an extra drag as it draws, which will give you tension changes and affect the quality of your stitch. Only stack wound threads should be placed on the vertical spool pin, which is when the thread is wound straight across.

Here’s some issues that might come up, and how to resolve them. 

If you find the thread is shredding or breaking, it can be caused by a few different things. If you’re already using the correct size needle, think about when you last changed it. Most regular needles need to be changed after 8 hours of sewing. A dull needle will not pierce correctly and will need to be replaced.

A needle that has a burr on it can also cause thread breaks. You can also check that the needle is pushed in all the way as otherwise, it will be too long and caused skipped stitches or thread breaks. A bent needle can also knock out the timing on your machine as the bobbin won’t grab the top thread properly and miss. This will also result in skipped stitches.

Another reason you might experience thread breaks could simply be that you’re sewing too fast. Slow the speed on your machine. If you continue to experience thread breaks, play with your tension settings and check your needle for any of the issues we just mentioned.

Because DecoBob™ is polyester, it’s a very strong thread that is actually stronger than a 60wt cotton. This is why we recommend it as your go-to utility piecing and bobbin thread. As the thread is much finer, it reduces tension problems and makes piecing look flatter, more professional, and makes it easier to line up your patterns.

InvisaFil™ is our solution to monopoly invisible threads. You know, that fishing wire thread that’s often a pain to sew with. InvisaFil™ is WonderFil’s finest thread line at 100wt, and because it’s so thin, it brings in a lot of other benefits that monopoly invisible thread won’t.

Because it’s so thin, it makes appliqué lay super flat. The thread also just disappears into the fabric, which is great for any application where you don’t want the thread to show. Apart from appliqué, it’s also amazing for stitch in the ditch where if you fall off your path, you won’t even see it. And also for any quilting where you need a thread to blend across multiple colours. On this quilt, we used a light grey InvisaFil™ colour to quilt the entire piece, but it just blends into every colour.

You can also use DecoBob™ and InvisaFil™ for machine embroidery, and you’ll find that these threads make a noticeable difference. We embroidered the same lace pattern using a 50wt thread and then again with DecoBob™ 80wt. Because the thread takes up less space, you’ll see that the pattern is less thick and more visible when using DecoBob.

InvisaFil is also fantastic for any smaller, detailed embroidery. You can see the difference when using a 40wt embroidery thread, then how much more detail you can keep at a much smaller scale when using 100wt InvisaFil™. It’s also fantastic for any embroidered lettering as the thread is able to give you straight, crisp edges that can’t be achieved with 40wt thread.

Have you used 80 or 100wt threads in your sewing machine? If you want to share how you used DecoBob™ or InvisaFil™ in your projects, let us know on social media! Message us on Instagram @wonderfilspecialtythread or on Faceback @WonderFil, or use #wonderfil to tag us.