Sorry about all the Murphy moments, Kris.
But truthfully, the people who have ti wear to wear a mask all day in the hospital (non-clinicians who don’t go into patients’ rooms) say the elastic is not comfortable. It makes the ears raw, and not all fit well.
i have been using only fabric . My friend who works at Hopkins in admin has been my liaison. I have made 27 so far, some with cotton ties, some woth the old t-shirt knit which are stretchy and comfy. She texted me today and said she got others from her church and everyone likes mine better. The church folks used elastic.
So , use up that stash, friends! I cut strips 1.5x WOF, subcut to 14-18” and sew into corners of masks before turning mask inside out. It takes a little longer than elastic, but it’s more comfort and more economical considering most of us have stash galore. Just be sure to iron and sew the raw edges under so they don’t fray. I forgot to do that my first batch of 13. What a mess! Lesson learned.