If you where creating this for a seam you would have your two pieces that make up the seam then an additional strip of fabric that makes up the piping.
To figure out the width of your piping strip you need to first decide the width of the exposed piping you desire. For example, if I wanted 1/4 inch to be exposed in my finished seam I would calculate as follows:
1/4" + 1/4" + 1/2" (Seam Allowance) + (1/2" Seam Allowance) = 1 1/2" TOTAL WIDTH
If you are sewing a straight seam, you can cut the strip on grain. If it is a shaped or curved seam you will need to cut strip on bias.
Wrong sides facing, press in half the strip lengthwise.
Right sides facing sandwich the piping strip in between the front and back piece. Line up all the raw edges and sew at 1/2" seam allowance (or whatever seam allowance you have decided).
We will only trim the following to the piping seam allowances:
- Trim 1/8" off one of the piping seam allowances.
- Trim the other piping seam allowance down to 1/8".
The staggering of seam allowance width will allow the seam to lay flat easier. You will notice in the photo, I pin the regular seam allowance out of the way while trimming to avoid cutting any unnecessary fabric away.
Your finished piped seam should look like this!
Photographed and written by Sheila Wong Studios