Six layers of satin - should be 93% (ish) protection
1. Take a single piece of 85cm x 33cm satin. No cotton needed.
2. fold it in half, sew it minimally to make that feel like a double thick 42.4cm x 33cm piece.
3. fold again to make six-thick 21x 33cm.
4. sew back and forth to make 15mm rows.
5. do the bulk of the https://cv-masks.github.io/ragmask-max.html operations on it - nose wire, stencil etc, sew, snip, edges.
6. Skip the stiffeners and retainers steps.
mins sewing time (no including making lengths of strap from sheets too).
2. high filtration (good self-protection as well as protection for others)
for general data, but two sections in particular for other percentages: