drpeter

Active Member with Corp. Privileges
448
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Wisconsin
Stevens Point
A Public Service Message:

The specialists are advising us to wear masks when we shop or go out to any space which is even partly public. Here's a quick way to make a mask, given their shortage in the markets.

An Indian doctor friend from Kansas City (an old schoolmate) posted this on my old school google group. Courtesy of The Times of India:

https://timesofindia.indiatimes.com...e-a-mask-in-30-seconds/videoshow/74987354.cms

A piece of square cloth and two rubber bands – that seems to be all of the easily obtainable components that are needed. Clever and inventive. I just tried it with a navy-and-white polka dot pocket square, and it works very well. Looks great too -- I'll try a paisley square next, LOL. It should be great for trips to the grocery store or pharmacy. I think it should be easy to wear as well.
 

Dhaller

Advanced Member
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Georgia
Atlanta
I saw this earlier today - I told my wife to go get her Hermes scarves! Not amused.

I was thinking of doing this along with HEPA inserts (I have a HEPA vacuum cleaner, so I would cannibalize some unopened filters): basically just insert a rectangle of HEPA filter into the cloth pre-fold.

DH
 

drpeter

Active Member with Corp. Privileges
448
United States
Wisconsin
Stevens Point
I saw this earlier today - I told my wife to go get her Hermes scarves! Not amused.

I was thinking of doing this along with HEPA inserts (I have a HEPA vacuum cleaner, so I would cannibalize some unopened filters): basically just insert a rectangle of HEPA filter into the cloth pre-fold.

DH
Interesting. The filters are a great idea. But I read that the COVID-19 virus is 60nm to 140nm in diameter, while the HEPA filter catches particles only up 0.3 microns in diameter (300 nm). So would an additional carbon filter of some sort be required to trap this particular virus? Or are there different grades of HEPA filters?
 

Dhaller

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Well, I experimented a bit, and found that human lungs can't generate enough suction to actually breathe through a HEPA filter; the airflow just goes around the filter.

(HEPA filters can capture 0.01 micron particles, which falls in the SARS-COV-2 range. HEPA's test standard is 0.3 microns, but actual NASA studies show that it captures much finer particles. Moot, since you can't actually breathe through it, though!)

Carbon filters aren't at all effective against viruses.

Practically speaking, what you want is simply a mask to prevent spittle projection; hence the CDC recommendation for a cloth mask as a mitigating technology. Still, the tinker in my will play around with some ideas.

DH
 

Dhaller

Advanced Member
2,242
United States
Georgia
Atlanta
I actually think a geometric solution, rather than an impermeability solution, might be worth exploring.

Imagine a mask of rigid material, such that it's composed of overlapping layers, so airflow is redirected through "switchbacks": gasses could pass through with ease, but particles (which need straight-path trajectories) would be impeded and captured.

I wish I had a 3D printer at home to prototype this!

(I am coming up with such a huge list of Stuff Everyone Should Own, from kettlebells to 1500 watt step-up transformers (long story) to 3D printers. Maybe a beer-brewing setup or still. Definitely a generator.)

DH
 

ran23

Super Member
1,230
United States
Oregon
Medford
I made a similar mask out of hounds tooth hankie, fogged up my glasses too much. yes, trying to exhale out of my mouth. I like the look of Japanese better grade masks.
 

mikel

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Staff member
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Los Angeles
Imagine a mask of rigid material, such that it's composed of overlapping layers, so airflow is redirected through "switchbacks"
You may find design inspiration in some anti-pollution cycling masks. While they may not have the switchbacks, I have seen some that are more rigid. Good idea though.