Cotton/satin version of Craig Turner's DIY "closest to an N95" mask.

His tutorial - "How To Make The Closest Face Mask To An N95" 

http://craigturner.com.au/how-to-make-a-close-n95-face-mask-equivalent

My version too 30 mins to make (faster for 2nd & subsequent I suspect) swaps out his non-woven materials (and use of an iron), and puts two layers of satin and a layer of 400-thread cotton in - with his template unchanged:

Sewn and cut out

Central seam joined with regular stitch, then zigzag stitch to secure thread ends from fraying:

Popped out (all from here on is 3D):

Retainer sewn in - stops fabric pulling on to nostrils/lips with each breath taken:

Zigzag stitch around the circumference (should have done
that earlier) and elastic ear loops added:

Nose wire sewn in with zigzag stitch.

Modifications for next one:

1. Leave a fabric tongue sticking out above the nose, then fold that
over and sew it down to make a sleeve for removable nose wire.

2. Change the shape of the retainer to something better lie a cross because
it needs to extend up&down a little over that vertical seam.

It is unclear whether Craig's original is hand or machine washable, but this one is. It fits quite well - I suspect that it's one size fits all for adults, but different people like different masks.

DeeDee in Craig's comments had also made a multi-layer cloth version of this design,
though there's no pics.

See take 2 where I try more layers of satin and moving the seam to the outside (and stiffening it)