The fabric tie we refer to in our patterns is essentially a strip of fabric where you fold the raw edges in, then fold it in on itself again to mimic the bias tape that is often purchased. Right now, bias tape is in short supply, but you absolutely CAN make your own fabric ties.
We have made a tutorial video with time-saving tips, and provided detailed instructions for you to download.
Also, if you access to the technology, you can consider 3D printing a fabric tie making tool, to make the process faster. You can make a device that folds 1-inch, 1.5-inch, or 2-inch fabric (bias tape) into strings for protective masks, so you can just sew the folded material.
DOWNLOAD: Thingiverse fabric tie maker page / Project Files
DOWNLOAD: Thingiverse fabric tie maker, with notches for pin / Project Files
Finally, there are bias tape making machines that you can purchase, which further automate the process.
For our mask patterns, we recommend 20 inch ties, times four ties, so you do need a bit over 6 feet for each mask. This is to allow the users of the masks to tie them in bows and repeatedly reuse them.
To make your own ties, you would use about 1.25 square yards of fabric per ten masks, or a little more than that.