This is a continuation of the anatomy lesson from the last post! A classic mistake we see on a regular basis with pleated sunburst accordion skirts has to do with the side seams and the center back zipper.
If you read my previous post titled Bias Skirts 101, you know their are 2 ways to cut a full circle bias skirt. One way is to cut 2 half circles, one for the front and one for the back. This way leaves no margin for error as you can only put a zipper on the side seam and the grain lines match up.
Below: A picture of two half semi circles. I placed the zipper in between to show its placement at the side seam.
It is the second way that opens up a pandoras box of problems…ripping and restitching over and over again. When a center back zipper is required (usually with dresses or gowns). That means you are cutting 1 half circle and 2 quarter circles. This way the 2 quarter circles can be used for the back and a zipper can be sewn in the center.
Below: A picture of one semi-circle panel for the front and two quarter panels for the back.
Now here is where the problem begins. It is a habit for most people to sew the center back along the selvage edge of the fabric. Which is the logical thing to do when you are cutting a garment on the grain. However, when cutting a bias garment or a circle skirt you need to account for all three grain lines.
So… if you sew a skirt with the selvedge edge along the center back (above), the grain lines at the side seams will be perpendicular. Look at the BLUE lines below.
Below: Perpendicular straight grain.
To have the correct placement of grain lines at the side seams make sure the selvedge edge runs along the sides and the cross grain runs up/down along the the center back.
Below: Notice the BLUE grain line runs in the same direction, as well as the GREEN cross grain.
Below: Close up of proper grain line placement at side seams.
Now, the amount of frustration you experience when you sew your garment can vary greatly depending on the type of fabric you use. All fabrics react differently in many situations so there is no fixed list of fabrics. Generally, stiffer fabrics like taffeta are less problematic than delicate silks. Fabrics that stretch more on the cross grain than straight grain are prime candidates. However, now that you have this information don’t take a chance. Follow the grain whenever you can and you will probably avoid countless hours of swearing at your sewing machine. If you have sewn a pleated skirt in the past and just realized this was your mistake, don’t feel bad. When it comes to pleating, many people are unaware of these techniques.