If you havesingle fold bias tape, fold and press one side towards the center, or if you have a strip of fabric, first fold the strip in half lengthwise and press, then fold one side towards the center fold and press.
If you have double fold bias tape, unfold and press one side open.
6. Mark the center point of your prepared seam bindings AND mark the center point of the raw edges of your mask. Your can be really precise and measure and mark with chalk or a fabric pen or just make a finger crease and eyeball it. I eyeballed it.
7. Lay the raw edge of the seam binding against the raw edge of the now pleated mask and sew it down.
Once sewn down, flip the seam binding over to the back, encasing the raw edge of the mask within the seam binding.
Almost done! All that is left to do now is sew down the length of your binding to keep the raw edges tucked in and tidy. Now repeat Step 7 for the other side of the mask.
8. You can take it to your ironing board and give it a good press but it sort of falls into place since everything has already been folded and pressed. Sew as close to the edge as possible to sew the binding closed, and you’re done!