Upgrading the 13 layer chiffon and 7 layer satin masks

Mid 2021 update: High thread count cotton and/or multi-layer polyester satin isn't a good choice for high filtration masks. They're not breathable enough at mid filtration performance. And additional layering to get to hight filtration still only decreases breathability further. With that they get hot and uncomfortable as well as giving your chest muscles a good workout.

The old plastic placement retainer snipped out, and a 15cm length of zip tie sewn in (zig zag stitch). I also added bias tape as the frayed edges were tickly and you really don't want an urge to rip a mask off your face in these times.

As ever the 13 layer mask is hard to sew because of the thickness of material under the presser foot. After I made it I'd emailed the authors of the Chicago/Argonne study:

 

1. I also looked at the materials and Jo-Ann product numbers in the supplemental info PDF. The researchers say that their "satin" was 97% polyester/3% spandex, but if you look up the item # 4488359 on Joann.com, the website says the material, Casa Collection Satin Solids Fabric, is 100% polyester.

 

2. item # 1636949, but on the website, that item number corresponds to a polar fleece print, not chiffon. (Did Jo-Ann change their numbering? Did the researchers make a typo?) For what it's worth, if you search for "stretch chiffon" on Joann.com, most of the results (Silky Solids, Silky Prints, Silky Stretch) seem to be 90% polyester/10% spandex, and although they don't look like my idea of typical chiffon, Jo-Ann is indeed calling them chiffon. I'd guess that might be what the researchers tested.

 

3. The phrase "polyester-spandex chiffon" actually refers to two or three different materials. The authors need to be more precise about the optimum fabric configuration in their test.

I heard back (May 12th):

Thank you for bringing this to our attention.

 

Sorry for the inconvenience caused. Please find the response to your queries below (response also posted on the reddit threads as replies):

 

1. Yes, there is an error. The correct composition is 100% polyester. The part number given is correct (4488359).  
2. Yes, there is a typo in the part number for chiffon. The correct part number is 16376949. Here is the direct link: https://www.joann.com/silky-solids-stretch-chiffon-fabric-peachskin/16376949.html
3. The idea here was to test the fabrics that can be easily procured. We used a chiffon that has a composition of 90% polyester and 10% spandex. And yes, we used the name from Jo-Ann.

It is great that authors are approachable, but I think that was a one-shot for me as I followed it with requests for raw data and additional tests, but heard nothing back.