When To Surge a Seam

Serging to finish raw edges before or after sewing the seam depends on how you will be pressing the seam allowances— open, or to one side. This factor depends mostly on the weight of the fabric. Lightweight fabrics tend to be pressed to one side, while heavier weight fabrics should be pressed open, to reduce bulk.

On a seam that will be pressed to one side, sew the seam first, then serge the raw edges together. On a seam that will be pressed open, stitch the seam first, then serge the raw edges independently, which will also help reduce bulk in the project.

It’s important to keep the serger knife out of the way when finishing seam allowances using a serger, to maintain the raw edges for even seam allowances.

For more on using a serger, check out these helpful videos:
Getting to Know Your Serger
Serger: Beyond the Basics
Serger Seam Allowances