Pressing Seams Open
(Achieving Ultra-Flat Blocks and Reducing Bulk)
@Fat Quarter Shop
@RileyBlakeDesigns
@Mary B
Step-by-Step Instructions:
While pressing to one side is traditional in quilting, pressing seams open is a highly effective technique for reducing bulk at intersections where many fabrics meet (like pinwheels and star centers), resulting in incredibly flat blocks.
Materials Needed:
- Hot iron (be cautious with steam)
- Ironing board or wool pressing mat
- Wooden seam roller or stiletto
- Tailor’s clapper
- Pieced fabric blocks
Tips for Success:
- Shorten your stitch length slightly (e.g., to 2.0 mm) when pressing open, as it exposes the stitches slightly more than pressing to the side.
- Be very careful with steam! Steam can shoot right up through the open stitches and burn your fingers.
- A wooden seam roller is a great way to “pre-press” the seam open before the iron touches it.
1. Set the Seam
- Place the fabric on your ironing board exactly as it was sewn. Press the hot iron firmly over the stitch line for a few seconds. This embeds the thread into the fabric, making the seam much easier to open.
2. Pre-Open the Seam
- Place the fabric wrong-side up. Use your fingers, a stiletto, or a wooden seam roller to gently coax the seam allowances apart so they lay flat on either side of the stitch line.
3. Apply the Iron
- Using the tip of the iron, press directly down the center of the opened seam. Do not slide or drag the iron, as pushing can easily stretch the bias and distort your block. Lift and place in an up-and-down motion.
4. Use a Tailor’s Clapper
- Immediately after removing the iron, place a wooden tailor’s clapper over the hot seam. Press down firmly and leave it there for a few seconds. The wood absorbs the moisture and traps the heat, forcing the seam to lay perfectly flat.
5. Flip and Final Press
- Carefully turn the block over to the right side. Give it one final, gentle press from the top to ensure everything is perfectly smooth and no little pleats formed along the seam line.
Top FAQs for Pressing Seams Open:
Will pressing open weaken my quilt? +
Pressing open does expose the stitches slightly more than pressing to one side, which historically made quilts weaker. However, with modern, high-quality thread and a slightly shorter stitch length (like 2.0 mm), seams pressed open are incredibly secure.
When should I choose to press seams open instead of to the side? +
Press open when you have highly complex blocks where multiple seams intersect at one point (like an 8-point star). Pressing open distributes the seam allowances evenly, preventing massive, hard lumps in the center of your block.
Can I still “stitch in the ditch” if my seams are open? +
It is not recommended. When you stitch in the ditch on a seam pressed to one side, you are stitching into a layer of fabric. If you stitch in the ditch on an open seam, you are stitching directly over the piecing thread, which can severely weaken the seam.
