The best (and worst) materials for DIY masks

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I remember hearing something from Lancet about a double layer silk and cotton being highly effective, something about an electro-static charge between material.
Anyone but me remember that?


Zippers. Seriously not good.


In what world is a 24-44% reduction in infection risk “slightly better than” 0?


While reading this article, the following ad appeared. I have no words.


The masks with pockets for filters sewn in are the ones I see most recommended. I just bought a couple like that, but I’m sure any competent DIYer can add a pocket with no problem.

Whether we’re talking about ads on BB for bead masks, mesh masks, zippered masks, masks with exhalation vents … any ad for a mask that defeats the purpose of COVID masks and undermines public health protocols … I’m told that your best bet is to alert them via e-mail at and/or . One they’re made aware of a problematic ad, the management usually does its best to rectify things.


The problem I found with a silk kerchief was that the weave was so tight that breathing through it was akin to what I imagine waterboarding is like - I could only draw breath very slowly, and not enough air was coming through to have anything resembling normal breathing.


I saw a young woman in pre-pandemic Brooklyn wearing a face mask made of black lacy panty material. Health and Goth fail.


The next best options, according to the research, are N95 and surgical masks

Surgical masks actually not the next best after N99 according to this:

Here’s an extract

Which type of mask should you choose?

The one that may provide maximum protection for the wearer, says Shivkumar, is a FFP3 respirator (a disposable shaped mask with a valve that filters air) “but we know that the production of them is more difficult and healthcare workers are not getting access to them, so it is important to reserve those for frontline workers who come into contact with Covid-19 patients”. And anyway, masks with valves – found on dust masks and antipollution cycling masks, for instance – are not thought to be effective at stopping the spread of Covid-19. A study by researchers at the University of Edinburgh into different mask types found that the valves improved breathability for the wearer, but would not stop infectious matter being breathed out. “For the public, cloth masks are fine,” says Shivkumar. “There’s not a lot of data on the efficacy of cloth masks but they’re better than nothing.”

How many times can you wear a disposable mask?

Jeremy Howard, a data scientist and cofounder of the campaigning organisation Masks4All, says you should really only wear one once. “They’re not designed to be worn more than once or cleaned,” he says.

“They’re not a great choice to use at all,” he adds. “Disposable masks are generally surgical masks: they’re designed to protect from all the stuff that might be coming out of the surgeon’s face during surgery. They have to do so many things that they’re not perfect at any of them. A cloth mask, on the other hand, can have a better fit and more absorbent materials, and can be reused as many times as you like. It really is a better approach.

Also @jlw - re the other masks thread today, another vote in this article for the dish-soap spectacles-defogging trick

No thanks, I don’t wish to inhale small particles from some cheap filter.

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I’d guess that they’re also much better than N95 masks at blocking air.

The company I work for sent me a pair of masks and insertable filters, but I’ve yet to find (or accidentally create) an opening in which to place said filter. Just checked again and the thing’s sewn shut.

It’s a pocket for filters that’s sewn in, not the filter itself. Obviously you want to put a good filter in there.

Well, that’s a design failure right there.

I haven’t asked but it wouldn’t surprise me if they told me “oh, just put the filter between your face and the mask.” (Or, they’d tell me nothing, which is the last response I got regarding a benefit snafu.)


Why are we still having to make homemade masks months into this pandemic? And why aren’t companies jumping at the chance to make real N95 masks given that they can sell every single one they can make?

(I mean we know one orange reason why, but I’d think that in this case capitalism would work, but instead capitalism seems more interested in just importing inferior, non-respirator grade masks and selling them as if they were respirators :-/ )


You won’t find any. You need filters that are medical grade, meaning they’ve undergone testing on their performance but also on the amount of particles they shed. Sadly even the medical grade filters are not rated for long term use, they quickly deteriorate and you would not normally want to re-use them.

I worry that people are putting themselves at more risk playing around with this stuff. It’s expected that people weigh risk poorly when they are scared.

I recommend just wear a normal cloth or paper mask as the CDC suggests. Use your mask to keep water droplets from being spread en mass when you’re in public. That much is broadly accepted and supported by evidence and by the main authority on the matter.

Masks as a prophylactic to prevent catching a virus is more controversial and more complicated. I spent a great deal of time going through conflicting information. I couldn’t narrow it down to where I could definitely say that you’d be protected from a virus like COVID-19 if you wore a mask. At this stage, I think anyone who asserts one way or the other has made an error. You may just have to accept that if you’re in an area where you could be exposed, that you can catch the virus even if you’re wearing a mask. I strongly urge taking precautions after that point, inform people you have come in contact with, and monitor your condition closely.

It doesn’t hurt for most health people to wear a mask, the cost is very low. And at the very least, it seems to prevent the spread.


I wonder how much those cloth mask filter inserts help anyways. Air is mostly going to go the easier route, which will be around the filter instead of through it. Replaceable filters really only make sense for real respirators, such as silicone half masks, that have a tight seal which forces air to go through the replaceable filter instead of around it.


Gas masks are the best.


I’ve made a bunch of masks for the family. Using patterns, or ideas from multiple patterns combined, and I’ve never once thought adding the filter pocket was a good idea. It’s still there on some of them, because the pocket is integral to the design allowing it to be turned inside out as part of the assembly. Sometimes sewn up afterwards.

The operational steps with a filter make it much more complicated. Sure, putting in the filter and putting it on is no big deal. But, after wearing for an hour, we treat the entire outer surface of the mask like it’s a bio-hazard. Plus, try not to touch the inside either. Remove it with the ear/head loops, holding those drop in a laundry bag without touching the mask, put in the washing machine, wash hands before touching anything else. A filter would add an extra step, “remove filter from between fabric layers that are a bio-hazard completely contaminating hands”. Then, you’re left holding the filter and the mask, filter disposal, hand washing, careful what you touch while doing those. Otherwise, you just cross contaminate a bunch of stuff and raise the risk that you touch something and then your face when you think you’re safe but have completely defeated the mask purpose. Instead of protecting you/others, it’s collecting virus and you’re using it to contaminate surfaces close to you.

PS: Quilting cotton is nice, it’s lightweight, maybe to light. Pillow case is nice and soft against the face. Tea towels have a nice weave (mostly) and hold a structure well, plus they’re easy to buy even when fabric is harder to find. Different fabric on the inside and outside is nice too.


Seems like you’d really need enough masks to rotate so you could let the mask sit for a number of days to let the Sars CoV 2 virus inactivate since the filter isn’t washable, unlike the cloth mask.

On the other hand, I’m wondering if you need to worry about treating the outside of the cloth masks like biohazzards since they are source control masks can cannot and do not filter aerosols as a respirator-grade mask can. If you were wearing a source control mask in a room with aerosolized Sars CoV 2 then you’ve already breathed it in and surface contact is the least of your worries.

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That sounds just as bad. I suppose you could have a line of buckets and drop in a different one each day. Still, we need enough masks for a family of 4, needing that many more would be a huge pain.

We’ve been working on the assumption that the mask can at least capture droplets. Droplets from the wearer on the inside, and random droplets from others on the outside. It’s a good question about how likely the mask is to capture a droplet that deposits virus on the outside while at the same time not having the virus migrate through the mask. I suppose we’re working on a assumption that after it’s landed, it needs some help to migrate from there. This could be completely incorrect, and just breathing through the mask may be all the help it needs. Still, I’ll error on the side of caution and assume there’s some danger and shouldn’t be touched.