We started by getting to know the machine, then we learned how to thread it, we sew straight lines, and then corners and curves! Following this infernal rhythm of learning, in today’s post, we will delve into the reverse of the work: the edges of the seam allowances. So that these edges do not fray, there are several techniques to finish them off that we will see little by little. Today, we will overcast the edges with the zigzag stitch, varying the stitch length and width depending on the fabric we sew. Let us begin!
STEP 1 sew a seam
- Join 2 pieces of fabric with a straight stitch 1.5 cm from the edge (this is the most common seam allowance).
STEP 2 Polishing the first edge
- Put the zigzag stitch on the machine.
- Find a middle stitch width and length. In the example, I have used a stitch length of 2mm and a width of 3mm.
- Turn the work inside out.
- Set aside the 2 fabric sheets and the left seam allowance, and keep only the sheet that corresponds to the right seam allowance.
- Zigzag sew along the edge.
If the zigzag stitch sags a little, it is indicating that the tension has to be loosened. As a general rule, the zigzag stitch is sewn with less tension than the straight stitch. Again, run tests on pieces of fabric to see the behavior of your machine.
STEP 3 Polishing the second edge
- Turn from top to bottom to start sewing the seam allowance left from above.
- Zigzag sew only the left margin sheet.
STEP 4 knotting the strands
- Make a knot with the threads of each beginning and end of sewing.
It is not usually secured with the back stitch in the seams made with the zigzag because the end result is not very polished (the zigzags do not coincide on top of each other, and there is a lot of noise).
STEP 5 iron the margins
- Pass the iron through the wrong side of the piece to flatten the zigzag topstitching.
And this is the end result of a zigzag open top seam. Zigzag offers other possibilities (such as overcasting the two seam allowances together) that we will see later.
You no longer have an excuse to leave your work plucked inside!