Written by Liz C.

On February 8 Bob Purcell, President of Superior Threads “and Self-Certified Threadologist,” taught Thread to a capacity audience assembled at the newly expanded and extremely sewer-friendly Fabrics Etc. 2 in Bensenville.

Here are some of the tips he generously shared:

Cotton thread that is glazed, waxed, or coated is not your sewing machine’s friend. The finish is nice and glossy, and the thread is fuzz-free, but the stuff the thread is treated with (wax, starches, chemicals) will rub off inside your machine. Instead use cotton thread labeled “silk-finish” or “polished cotton” for machine sewing. These are nicer names for what is technically “gassed” thread that’s passed near a flame at a high speed to burn off fuzzies.

How can you tell if an old spool of cotton or silk thread is still good? Take a few inches and pull it apart from either end. If it breaks with a nice clean snap, it’s fine. If it frays before it breaks, get rid of it.

“Mercerized” cotton just means it’s been treated in a solution that makes the fibers swell so the dye will work better and the thread will be stronger. It’s pretty much a given, whether or not the label says it.

It’s also a given that cotton thread is short-staple (meaning 1-1/8”) unless it says specifically that it’s long staple (meaning 1-1/4”) or extra-long staple (meaning 1-3/8”). These measurements actually make a big difference in the amount of lint the thread will produce.

Egyptian cotton is likely to come from somewhere other than Egypt. Egypt is the world’s 10th largest cotton producer [China is first], and it simply doesn’t produce that much. Probably what you’re looking at was produced from seeds from Egyptian crops that themselves were produced from seeds that merchants in the late 18th century brought to Egypt from the American south, where a particularly good South Sea cotton was growing.

And it’s not true, Purcell explained, that if you use polyester thread on a cotton fabric the thread will cut the fabric. Compatibility depends on the thread’s strength, not its poly content. He unspooled a cotton thread and a poly thread and asked us to identify the poly; we all guessed wrong except for one Fabrics Etc. person.

How can you assess the quality of a metallic thread? Pull out 3 feet and drape it between your hands, holding your hands about 6” apart. If it curls, it’s bad. And there’s a lot of bad metallic thread out there. Try to buy metallic thread that’s wound on wider cores, by the way. Less twisting.

Finally, did you know that polyamide is simply another name for nylon? Nylon melts, so don’t use nylon thread unless you’re using it as a fusible thread.

Purcell is full of really useful information you can’t believe you’ve lived without for so long. For more of it, go to There’s even a newsletter….

2 thoughts on “Threadology

  1. Pingback: How To Thread « ASG Chicago

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