Pressing to set seam allowances before they are pressed to one side is one of the easiest ways to improve the accuracy of your patchwork quilts. It's an extra little step, but make setting seams a routine practice and I know you'll be happier with the finished quilt.
If you're having trouble sewing an accurate quarter inch seam allowance the problem might not be your allowance at all -- it could be a result of improper pressing,
How Does Setting a Seam Help Improve Patchwork?
When we sew fabrics together, the narrow channel along the seam is occupied by a thread. No matter how accurate we are, the fabric on each side of the thread will puff up just a tiny bit and that teeny extra height, called loft, could become 'lost' in the seam when it's pressed to one side.
Pressing to set the seam helps remove those little puffed up areas. Setting a seam will make patchwork lie flatter than it would if you simply press to one side or sometimes open, which we do to make quilt backing or to reduce bulk.
How to Press to Set a Seam
- Before you press a seam allowance to one side, place the sewn patchwork unit on an ironing board, unfolded, just the way it looked after being fed through the sewing machine.
- Place a medium to hot iron on the patchwork. Don't move the iron back and forth, simply allow its weight and heat to help the patchwork lie as flat as possible, setting the seam and flattening puckers.
- We rarely use steam when we're making a quilt because we feel that steam increases the likelihood of stretch. Setting a seam is one exception to my own little 'rule,' because we don't move the iron at all.
This method is especially helpful when you use strip piecing techniques because it helps stabilize the strip sets and prep them for further pressing.
We encourage you to try both steam and dry pressing to see which method works best for your own style of sewing. Remember, there are no rules in quilting, only guidelines, and sometimes it's perfectly okay to ignore those guidelines.
Chain Piecing Makes Setting Seams a Breeze
If you chain piece your patchwork, you will probably have multiple units on your ironing board at the same time, all waiting to have their seam allowances pressed to one side. The extra 'setting' step adds just a few seconds for each unit and will improve the accuracy of those units once the seams are pressed to one side.
More About Seam Allowances
Read how to press seam allowances for more information, and remember, we press when we make quilts -- we do not iron!