Monofilament thread (a.k.a. “invisible” thread) is similar in composition to extremely fine fishing line. It comes in clear and smoke, the clear for use on light fabrics and the smoke for use on dark fabrics. Monofilament thread is strong and not difficult to use; however, there are a few tips and cautions I’d like to pass along.

I generally use monofilament thread in the top of my sewing machine and regular thread in the bobbin. If you use monofilament in your bobbin, wind the bobbin slowly as the winding process will generate heat with this thread. For the same reason you should sew more slowly when using this thread. Loosen the top tension and sew a test piece to check the stitch prior to sewing on your project.

If you do decide to wind a bobbin with invisible thread, you may need to loosen the tension on the bobbin case. You must be VERY careful if you do this, as it can be difficult to reset the bobbin tension. I have an extra bobbin case for just this purpose. I do not change the settings on the bobbin that came with my sewing machine.

Cautions: You should not use invisible thread on any item intended for a child under the age of three. If used in a quilt, for example, it’s possible that a small child could wrap a loose thread around his finger and cut off circulation. It’s very difficult to see on a little finger.

Also, you must be very careful with this thread around pets who can easily swallow it. Cats are especially susceptible. Invisible thread will not show up on an x-ray and can cause a section of the animal’s intestine to become blocked. If your pet swallows this thread and begins to pass it in a BM, DO NOT attempt to pull the thread out of the rectum as it can knot around the intestine or bowel. Instead, simply snip off the end as it passes out the rectum. If your pet seems in distress, be sure to contact your vet.