Curved bodice seams don't match? Here's what's going on

Working on a pattern with a curved bodice seam and it looks like there's no way it's going to fit together? It's not a pattern mistake, it's just the seam allowance!

Both the Georgian Polonaise Dress and the Romantic Wrap Dress include a curved seam at the back of the bodice. When the seam allowance is added to this curved seam it's being added to opposite sides of the curve, which makes the back bodice piece look smaller and the side back bodice look bigger.

Because of this optical illusion, the side back pattern will look like it's way too tall. No, you didn't cut out the wrong size! Keep reading for tips on how to check this seam and how to sew it together.

 

Checking the Seam

When sewing curved seams like this, I highly recommend that you start by marking your stitch line on both sides of the seam – this is 1.5cm from the edge. Use a temporary method for this (chalk, heat vanishing pen, etc.) and mark on the wrong side of the fabric.

Once your stitch lines are marked, you can compare the lines on both pattern pieces. You'll want to overlap the lines themselves, not the cut edges of the fabric. Again, the cut edges will look misleading because of the seam allowance.

The curves on your back & side back pattern pieces won't be exactly the same shape, but they should be the same length. Match up the stitch line at one edge, then slowly 'walk' the seam down to the other edge, as shown in the clip above.

 

Sewing the Seam

After comparing the seams lines, hopefully you're feeling reassured that the pieces will fit together, and ready to start sewing them. Here's how:

 

 

1. Match up any notches and pin these together at the stitch line.
2. Match up the top and bottom of the seam and pin these together at the stitch line.
3. Add additional pins midway between existing pins, distributing the fabric evenly.
4. Repeat step 3, adding additional pins between existing pins, until the entire seam is securely pinned.
5. Sew the seam with the convex curve (the side that curves outwards) on the bottom.
6. If you're making the Romantic Wrap Dress, press the seam allowance away from the convex curve (towards the centre back of the bodice). If you're making the Georgian Polonaise Dress, press the seam allowance open (this reduces bulk, since the bodice has more layers).
7. If needed, clip into the seam allowance to allow the curves to lie flat.

 

Want to see a demonstration?

The tutorial video for the Georgian Polonaise Dress goes into more detail about this seam, including how to 'walk' the seam to check the length, how to pin it, and how to sew it. 

This explanation starts at 3:30 https://youtu.be/aWXczIU0T48?si=Fy0xdkJOjAXtFCGU&t=210