Shirring with elastic thread is when the elastic thread is on the machine's bobbin, instead of sewing thread. As mentioned in my post, Shirring Fabric With Sewing Thread, it does resemble smocking in a way and the elastic thread certainly creates beautiful soft gathers that is figure hugging,flexible and great to use in necklines, waistlines and even on sleeves of dresses and tops.
This is a top I bought a few years ago of which the waistline is shirred.
I used polyester suiting for the slacks.
Mark a few rows on the right side of your fabric with a fabric marker.
The quilters guide of your machine can also be used once you have marked the first row.
Thread the machine needle with regular thread and adjust the stitch length between 3 and 4 mm. Wind the elastic thread on the bobbin by hand while stretching it very slightly, until the bobbin is almost full.
Place the bobbin in the machine and pull the elastic thread through the hole just like you do with regular sewing thread. Sew a test sample on a piece of scrap fabric first.
For a looser tension, adjust the bobbin casing screw slightly.
Hold the fabric taught and flat by stretching it at the front and back while sewing.
When all the rows are completed, draw the sewing thread through to the wrong side with a needle and tie knots with the elastic thread.
Machine stitch a line across the knots to secure it.
Have a jolly good week further!