We did a project at a quilt show using the thumb tack method.
The design was to applique circles onto squares for the blocks.
We set the thumb tack and sewed a bastng stitch circle and then cut out the circle leaving about a 1/2" seam allowance outside the stitching. Then we took a used CD and placed in center and drew up the basting threads and tied the thread. Evened out the edges and pressed with a steam iron and had a perfect circle that then was machine appliqued to the square. Cut the circle from the back of the appliqeed circle and then trimmed the seam allowance. It made a really quick block. The heat from the iron didn't effect the cd.