Differences Between Thread Weights: Where to Use Them & How They Look

Your standard thread will often come in a medium 40 or 50 weight. But a huge variety of other threads exist in super fine 100 weight, or super chunky 3 weight options too. In this video, you’ll learn how these different weights of thread will show up (or not be seen at all) and where they can be used for the best advantage. Sew like a pro when you understand how thread weight influences your stitching!

Whether you want the thread to blend in or sparkle and show off, choosing the right thread will make all the difference in your projects.

1.     Medium Weight Threads

These are the types of threads that you will most frequently find, most often 40 or 50wt. They can be used for most construction, quilting, machine embroidery, sergers, and general purpose sewing.

Medium weight threads can be made from all types of materials including cotton, polyester, rayon, and even metallic. This thread weight will blend or show up depending on what the material is made from. Therefore, a cotton will blend more than a metallic will. But if you really don’t want your thread to show, you may wish to consider a different weight.

2.     Fine Weight Threads

Fine weight threads run from 60wt to 100wt. These smaller threads are ideal for intricate work such as micro quilting and fine detailed machine embroidery like freestanding designs or monograming.

They can be made from cotton on the larger end to polyester on the finer end. The fine threads blend better and take up less space, so they’re ideal for hand & machine appliqué, stitch in the ditch, English paper piecing, and micro quilting. Dense quilting will also leave quilts softer, more flexible and lighter as the thread doesn’t take up as much space or add as much weight.

Quilting with InvisaFil™ 100wt, a light grey blends in with every colour.

This 80wt cottonized polyester thread called DecoBob is our favourite piecing and bobbin thread. Because it’s so fine, it makes seams lay flatter and crisper when piecing. This is especially useful when it comes to foundation paper piecing or when you need to accurately match up patterns and blocks. It’s also incredibly strong, making it a reliable choice to hold your quilts and projects together.

Piecing with DecoBob™ 80wt.

As a bobbin thread it is unsurpassed. The fine thread can be paired with any top thread including thicker threads. It greatly reduces tension problems, lets your seams lay flatter and look more professional, and as a bonus, allows your bobbin to hold more thread since the fine thread takes up less space.

3.     Heavy Weight Threads

Heavy weight threads range from 12wt – 3wt. 12wt threads can still fit through the eye of a sewing machine needle, so you can do some incredible stitching with this thicker thread. Whereas 8wt and heavier threads are not recommended as a top thread.

Use 12wt for bold machine quilting, big stitch hand quilting, thread painting, decorative stitching, hand embroidery, sashiko, big stitch hand quilting, crafts, and even hemming jeans. When using it on the machine the thicker thread will stand up from the fabric giving you a wonderful textural effect.

Decorative stitching with Fruitti™ 12wt cotton thread.

8wt threads and thicker the most commonly used for hand embroidery. Even though they’re too thick to fit through the sewing machine needle, you can still do couching and bobbin work with it on a machine, or use it in the loopers of a serger. 8wt and thicker can also be used for the same things as 12wt, in addition to crochet and knitting.

Still have questions about thread weight? Let us know in the comments. Ready to start sewing? You can find a list of stores that carry WonderFil threads on www.shopwonderfil.com/shop-local/. You can also sign up to receive weekly sewing tips, free patterns, and tutorials in our newsletter. Register by clicking here! You can unsubscribe at any time by clicking the unsubscribe button on the footer of every email you receive.

How to Sew Heavy Specialty Fabrics (Leather, Vinyl, Cork)

If you’re working on a project that requires a heavy material such as pleather, vinyl, or cork, don’t fret. While these materials might seem a little intimidating if you don’t have a lot of experience sewing with them, they only require a few simple adjustments. Simply using the right needle, thread, and understanding the material is all it takes to sew with these fabrics and easily as any other!

The tools you sew with can make a big difference. Consider swapping out your regular needle for a super non-stick universal needle. These needles have a coating on them that glide through the material and is especially useful if you have a tacky stabilizer underneath. If you’re sewing through a particularly heavy pleather or vinyl material, you can also switch to a leather needle. Leather needles are designed for piercing through these particularly resistant materials.

You can also change your presser foot for a non-stick or Teflon presser foot when sewing on pleather or vinyl. These materials can stick to the bottom of a regular presser foot, which impacts your stitch quality. These non-stick feet have a super slick surface that prevents that from happening.

Pictured: Non-stick sewing foot

If you don’t have a non-stick presser foot or they aren’t available for your machine model, you can also use a walking foot. These feet are designed to provide a second set of feed dogs from the top of the fabric, which helps push these specialty materials through.

Pictured: Walking foot

The thread that you sew with is also important to think about. Because cork, pleather and vinyl are much thicker, you’ll want to use a stronger thread to keep it together. Especially if the project you have in mind will require some durability. 

HomeDec™ is an enhanced polyester thread designed for extra strength. It comes in three weights: 30wt, 40wt, and 60wt. Because this thread is so strong, we don’t recommend using a normal bobbin thread with it. Always use the 60wt HomeDec™ in the bobbin with itself. The slightly lighter weight thread will help reduce the seam bulk, which is especially useful when dealing with thicker materials.

On your sewing machine, consider increasing the stitch length slightly. With pleather, vinyl, and cork, you’ll be piercing the material with permanent holes. Having the stitch length too low means the holes will be close together, causing damage to the material and compromise its durability. Since you’ll be sewing with an enhanced strength thread like HomeDec, the thread will easily compensate for holding together your seams even with the longer stitch length.

Because holes pierced through these materials are permanent, you won’t be able to use pins without leaving ugly holes behind. You can instead hold your pieces together using wonder clips. These will pinch your material together without needing to put holes in them.

But what about if you need to clip something that isn’t close to the edge, such as appliqué? Unfortunately, many pleather and vinyl materials will melt even on very low heat, making it impossible to use an iron-on appliqué. Take some scotch tape and tape over the appliqué piece so it doesn’t shift. You can then stitch through the tape and around the appliqué with a straight or decorative stitch to hold it down permanently. Afterwards pull away the bits of tape to clean it up.

Since you can’t use an iron on many pleather and vinyls, we recommend using a seam roller to help press your seams. This tool is a must for any material that can’t be ironed and is much more effective than simply finger pressing open a seam.

We hope these tips make it easier for you to sew with these heavier specialty fabrics! Let us know on on social media what project you’ll be sewing with pleather, vinyl, or cork. Instagram @wonderfilspecialtythread or on Faceback @WonderFil, or use #wonderfil to tag us!