16 layers of spunbond NWPP in a mask

 

Three masks pictured together. Left to right

1. 8 layers of 38 gsm spunbond NWPP plus one layer of 180 TPI cotton outer. 
2. 16 layers of 38 gsm spunbond NWPP (no outer layer)
3. 6 layers if cheap polyester satin (no outer layer) - straps stolen for mask #2

Mask #2 is the new one - 6 mins to make. Or would have been 

if the needle didn't break in a 5mm 48-layer intersection.  The needle tip is still in the mask :(

Mask #2 is 608 gsm of spunbond NWPP (or 672 gsm 

if we go by my weighing of the fabric)

Mask #1 is what I wore today for 8 hours in an 

office setting. In this pic, washed but not dried.

Masks #1 and #2 are easier to breath through than 

mask #3 (which is why I gave up on satin). Yes, I have 

checked mask #2 for breathability.

Wearing the 16 layer NWPP mask

It is fine. Comfortable. Breathable - I can fill my 

lungs from zero in about a second and empty just as fast. 

The fabric, as before, is fine against my face. It doesn't smell. 

Calculations

Filtration effectiveness for 608 (or 672 gsm) is total guesswork at this stage because of leaks or weird innefficiencies.  Calculations make this mask look like it would perform at 95% filtration efficiency.

Tests results pending.

Studies: Long et al and Maker Mask test results (Nelson Labs)

Layering calculations: https://math.stackexchange.com/q/3698080/794361

 

Pattern 

RagMask Max with simplifications as there's no outer cotton layer.  See construction video, too.

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Bonus pic: Mask #1 drying on the radiator. Well, the 

radiator is not on presently, but it will be later:

Bonus pic 2: Broken needle in fabric:

I can't pull it out. I think it still has the thread going through its eye.