Elastic thread is for shirring — the rows of soft gathers on sundress bodices, cuffs and waists. It goes in the bobbin only, never through the needle.
How shirring works. Wind the elastic thread onto a bobbin by hand, with gentle even tension and not stretched. Thread the machine normally on top with ordinary thread. Sew parallel rows on the right side, about 1 cm apart, with a stitch length around 3 to 4 mm. The fabric barely gathers at first, then draws in as you add rows.
The finishing step people miss. Steam the finished shirring. Hold the iron above it and let the steam reach it without pressing down. The elastic contracts and the gathers tighten dramatically. Before steaming, shirring often looks like a failure.
What to check on your machine. Some machines shirr happily with the bobbin case as it is; some want the bobbin tension loosened slightly. Test on a scrap first, because unpicking shirring is tedious.
Fabric choice. Light wovens — lawn, voile, light cotton, rayon challis. Heavy fabric will not gather, and knits do not need it.
Mark the rows, or run the edge of the presser foot against the previous line, so the spacing stays even. Uneven spacing is the fault that shows.
Hold the fabric flat as you sew each new row, since it is already gathered from the ones before.
And leave long tails, knotted at each end, because the rows cannot be backstitched.
Questions people actually ask
My shirring barely gathers.
Add more rows, and steam it. Most shirring only looks right after both, and the steaming step is the one usually skipped.
Can I use elastic thread on top?
No. It will not pass through the tension discs and the needle correctly. It belongs in the bobbin.
Last reviewed 2026-08-11