Thread by @RowennaM

So, I'm still seeing stuff circulating about how fabric masks are "useless" even as the CDC recommends more widespread mask usage and some local governments require it.

Friends--homemeade masks can help prevent the spread of disease BUT YOU HAVE TO DO IT RIGHT.

This is important because med-grade masks SHOULD be reserved for those folks on the front line who need them the most.

Let me repeat that--when I say "wear a mask" I am NOT saying "wear a med-grade mask or N95 respirator that a nurse needs more than you."

That's out of the way. OK.

Hard truth, no homemade mask of non-med grade materials will filter as well as an N95. But we shouldn't let perfect be the enemy of good--condoms aren't 100% effective but we certainly recommend wearing them, right?

And research DOES show that a fabric mask can filter SOME fine particulate: cambridge.org/core/journals/…

(And this tested T-shirt material, which is...not the greatest choice, TBH.)

Thing is, wearing a mask serves more to protect OTHERS than to protect YOU. If you are one of the asymptomatic or pre-symptomatic folks with COVID (and since we all have Schroedinger's Virus right now, assume you are), you don't want to exhale clouds of Nasty on others.

Like, just keeping your sneezespray to yourself seems worth it: smithsonianmag.com/smart-news/slo…

(I mean...ew.)

This was the principle behind countries that instituted mask-wearing, such as the Czech Republic. Yet it seems worryingly American that every time I talk mask-wearing with friends, their first objection is that the protection for THEMSELVES is imperfect 🤦‍♀️

Yep, it is. But it's not solely FOR YOU. It's to protect others, too.

Let's move on to best practices.

Use good fabric.

Unless you have access to med-grade fabric (there's been some success with autoclave sheets: anest.ufl.edu/clinical-divis…)...

...(Including ONE Of these patterns passing a "fit test" as a commercial respirator would: )...

But since most of us DON'T have access to this kind of material, and even if we do, we should probably give it to medical personnel:

Use high-quality, densely woven cotton broadcloth/quilting cotton. newsroom.wakehealth.edu/News-Releases/…

Now, unfortunately, most medical professionals aren't sewists and one piece of advice circulating is a bit suspect:

https://twitter.com/RowennaM/status/1246131512841560067?s=20

Why cotton? Not only does it filter well, it's widely available AND it stands up to repeated high heat washing.

And that's important, because a dirty mask is not helpful.

There's some evidence that DAMP masks could be worse by harboring virus LONGER. bmjopen-2014-006577

If you're going to make and wear masks, treat them as a contaminated item after wearing. Don't wear so long that it's damp. Wash in as high of a heat as you can (unless you have an home autoclave, your washing machine or a pot of boiling water will have to do ;).

Don't share masks, don't take it on and off while out and about. Don't touch it, just as you don't touch your face. Wear over your mouth AND nose (YEP). Common sense here, people.

As to pattern--there are two main types of mask patterns, pleated and curved/shaped.

Both work to create a mask that fits over the curves of your face--the pleats spread out, and the shaped version is sewn in two halves and makes a shape like a bra cup.

The keys, from my understanding, of the best-performing masks in terms of FIT (ie, less Nasty sneaking through the top and sides) is that they have metal shaping pieces over the nose bridge and have both ties and elastic.

And these may prove stumbling blocks for the home sewer because finding elastic is currently tough AND metal wire of the right gauge isn't something most people have lying around their houses.

But you don't need to be perfect to sew SOMETHING. Moreover, elastic breaks down under repeated high-heat washing, and can be less adjustable, so ties alone are in some ways preferable.

Pleated: The Deaconess pattern is widely circulated. deaconess.com/How-to-make-a-…

Pro: VERY EASY. Minimal fabric. Uses ties, not elastic.

Con: Only one layer of fabric, which isn't as good as 2+ layers. (You could simply sew two layers together)

Shaped: The HK Mask comes in multiple pattern sizes: diymask.site

Pro: Two layers with a pocket for an extra filter, multi-sized for fit

Con: More advanced sewing required. Has elastic (can be eliminated and still works)

This is the pattern I use. Two layers of quality cotton with a pocket for a filter. This one turned out a little wonky but fits me pretty well. I didn't have anything for a nosepiece, which is a downside.

(A note on the extra filter--the pattern claims percentages from varying filter types but doesn't provide research. That said, separate research has shown old-school vacuum cleaner bags work well, so....! I use a folded coffee filter because it fits into the mask well.)

And this hybrid pattern, which is both shaped and pleated: instructables.com/id/AB-Mask-for…

Pros: Double layer, no elastic, can fit OVER an N95 to extend its life according to designer

Cons: More advanced sewing required.

Finally, if you can't sew a lick, this is better than nothing! huffpost.com/entry/how-to-m…

So long story (VERY LONG sorry) short--mask wearing is supported as a measure to reduce spread of disease and should probably be implemented more widely. Wearing a mask is the neighborly thing to do. You can make one at home. Don't use PPE needed by med workers. End Scene.

Update: the CDC posted this guideline: cdc.gov/coronavirus/20…

Based on the Wake Forest research cited above, I would personally avoid the T-shirt option. Aim for tightly woven, high quality cotton.

And PS the bandanna version will work with an unfinished length of cloth, too. Just cut to size. The edges will unravel over time but if you don’t mind, I don’t 😉