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One of the most common requests we receive is for help selecting the best thread for a project. The types from which you can choose can seem almost endless when you’re staring at the hundreds of pretty spools at your favorite retailer. We turned to our friends, Ellen March and Pamela Cox from Sulky America for some expert advice – particularly about cotton thread options. Read on for their insights and information as well as to find out which myths they’re bustin’. 

Choosing the right thread for your project is an important factor that determines the final look, feel, and oftentimes longevity, of the project. With so many choices, how do you decide?


Think about thread sheen in the same way you think about choosing paint for a room. Do you want the thread to shine, glisten, reflect light, look slick, look matte or be textured? These decisions will determine how to choose the right thread for your project, specifically whether you choose between rayon and cotton. The photos below show you the same color of thread (Sun Yellow) in two different sheens: rayon and cotton.

Sulky 30-wt Sun Yellow Cotton Thread

Sulky 40-wt Sun Yellow Rayon Thread


When choosing the right thread, decide if you need the thread to hold up to heavyweight fabric, seams that will undergo stress, or stitching that is likely to require lots of washing and wearing. These factors will determine the properties of the thread you need. A polyester fiber is very strong and lasts well over time, but cotton thread might be a better choice – especially if you’re working with cotton fabric.

The thread weight also comes into play when considering strength. The lower the weight, the thicker the thread.

In general, the rule of thumb is to choose polyester thread if you’re working with a man-made or synthetic fabric. If working with a cotton fabric, choose cotton thread. But if you’re choosing thread for quilting or machine embroidery that theory goes out the window. Plus, breaking the rules is so fun, isn’t it?

Virtually any thread is suitable for quilting, as long as it’s good quality, long-staple thread. The same is true for machine embroidery. To understand the standard Sulky follows with all its products, watch the manufacturing process of Sulky cotton thread. The video below shows the process during the manufacturing of the popular Cotton + Steel 50 wt. cotton thread, however, the Sulky quality framework is the same for 30 wt. and 12. wt cotton.

Machine Embroidery

There is some debate as to whether or not cotton thread is suitable for machine embroidery, and it really depends on personal preference. 40 wt. rayon is almost always chosen by the digitizer when she/he is creating designs, so it’s important to consider what was intended before deviating. Always perform a test stitchout; you might be surprised by the look of cotton in your design. The image below shows rayon on the left, cotton on the right.

Bouquet of Flowers Collection by Graceful Embroidery – Available here

The rayon on the black fabric allows a hint of the foundation fabric to show in the centers of the white flowers. Also, there is a bit more detail in the outline of the top yellow petals and the stamen.

The cotton thread gives off a vintage vibe and also has more of a matte look. It makes the design heavier and more dense. Some details are less evident.

The image below compares rayon30-wt cotton and 12-wt cotton. You can see how thread weight plays a part in how pronounced the stitches are, and you can spot how the different sheen of each is evident. In general, 12 wt. thread should be used mostly for outline embroidery designs and requires a 16/100 needle.

Remember that 30 wt. is about one third heavier than the traditional 40 wt. thread with which you may be more familiar. If your test stitch-out shows crowding or breakage, you might need to enlarge the design just slightly to accommodate the increased thickness.

A common myth about using cotton thread for embroidery is there will be increased thread breakage. However, if using a high-quality thread and the correct needle, breakage is minimal, if not non-existent. Sulky only uses long-staple fibers to twist into quality cotton thread. Those longer twisted filaments offer fewer “break points.”

Take the time to read and compare the information provided on spool caps. Just like the mandated information found on fabric bolt ends, thread companies must disclose content and care. If proud of filament length, they will also state “long staple.” That’s how to tell the difference between mediocre and high-quality thread.

The Need for Speed

The most common reason any thread breaks is due to friction, not due to the thread itself. Between the speed of the machine and the frequency with which a needle must penetrate into the fabric, often in the same area, heat is produced, creating weak points on any thread. Synthetic threads are man-made and withstand higher friction or heat, before breaking. However, this is not to say that the natural cotton thread isn’t suitable for machine embroidery.

After ensuring that a quality Sulky cotton thread is threaded into the machine, slow down the machine speed by at least half to reduce friction.

A topstitch needle is often the best choice when embroidering designs in cotton thread. Topstitch needles have the large eye necessary for thicker thread to more easily pass through.

Topstitch needles are also available in larger gauges than standard embroidery needles. Larger needle gauges are helpful when embroidering in cotton thread on heavier fabrics, such as denim or duck cloth.

Fuzz Control

One negative truth about cotton thread is that it produces lint during the stitching process. However, the beautiful final result of a design machine-embroidered in cotton thread far outweighs any slight inconvenience of the lint by-product.

All you need to do is clean the lint off the presser foot during thread color changes. You can remove any excess lint that might fall during embroidery using painter’s tape or masking tape.

After embroidering with cotton thread, also check your machine’s bobbin case for excess lint and clean, if necessary. 

Go ahead… break the “rules” and give cotton thread a try the next time you test an embroidery stitchout for a project. You just might find a new favorite thread that gives your projects a signature look.

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