If you are unfamiliar with the concept of shirring, it's basically replacing your bobbin thread with elastic thread. When you sew your rows of stitching, the elastic bobbin thread is slightly stretched while making it's way through the machine, making the most perfect little gathers! Elastic thread is something that is readily available, you can find it is most sewing store and I actually picked mine up at Wal-Mart in the sewing section.
Woven or Knit Fabric
The formula that I use in order to determine how much fabric is as follows:
Width= Take the chest measurement of whoever you are making the dress for, double it and add 1" for seam allowance.
Example: 20" x 2 + 1+ 41"
Length = Take your desired finished length and add 2" for seam and hem allowance.
Example: 15 1/2" +2"= 17 1/2"
So the finished rectangle that I ended up with measured 41" x 17 1/2"
Hand wind your bobbin with the elastic thread. Don't stretch the thread to much when winding.
Fit your bobbin into your sew machine as you usually would.
Press down an inch of the top edge of your rectangle lengthwise. This is to finish off the edge!
Start stitching! I'm using my presser foot as a guide and it's about 3/8" from the edge.
When you get to the end of the row leave a few inches of both elastic and thread. You can tie off these ends now or wait till you're finished and try them off then. This will help prevent unraveling in the wash.
When working on your second row, and all other subsequent rows, gently stretch out the previous gathers so that you are stitching on a flat surface. This keeps all your rows of gathering even and it's much easier to sew straight when you stretch it out a little.
When your bobbin filled with elastic thread runs out in the middle of a row unpick some of your stitches so that you have an inch or two loose. Refill your bobbin with elastic thread and start stitching right where you left off. When you complete the row, go back and try your two loose ends into a tight knot.
How pretty does that look! I ended up stopping at ten rows and only had to refill my bobbin once. If you are making an adult version you might need more rows. You can also space them further apart. I recommend testing it out on a scrap piece to see what you like! If you haven't yet, nows the time to tie off all your loose ends.
Stitch your back seam closed. If you are working with a stretch fabric, remember to use a stretch stitch. Finish off your edge using a serger or zig zag stitch.
Zig Zag the bottom edge of your dress and turn up an 1" and press. The zig zag stitch helps to stabilize your edge and makes it much easier to work with. Stitch down!
When hemming I also sew with the right side up. This results in a much neater stitching line. Just make sure that you are constantly catching all layers.
To determine the length of the straps, try the garment on and measure front to back over the shoulders. Add a little extra for seam allowance. You can make these as wide as you like!
I made mine 1" wide and 9 1/2" long. I attached them to the center back of my dress to give a nice little detail.
Thanks for reading!!!