the handoff!



to your point, and just per my intuition, it seemed to me that if the virus is embedded in droplets - which is what I've been reading - that it's the airborn or surfacebound droplets that carry the virus payload. the N95 filter is for particles that are airborn, rather than traveling the galaxy inside a little spaceship of water.

if you are infected, and the mask keeps the droplets from disbursing into the atmosphere through your cannon of a sneeze or cough, good. if the mask keeps an incoming droplet from making its way past layers of fabric, also okay.

i could imagine a droplet drying. leaving viruses on the outside layer. and now the virus isn't in a droplet spaceship. now the virus is a little spacewalker, which is small enough to move past the layers of fabric as you're sucking in oxygen. that's a problem, perhaps.

so i'm intrigued by the concept of a pocket, inside of which you'd place a filter. sort of like your coffee machine. the grounds stay out. the water moves through the filter.

in this case, what's needed is the material for the filter, so that when you suck in air, you aren't sucking in little spacewalkers.

in my mind's eye, i see a test. the sort of test they'd do in a village in the jungle, where you have no high tech lab. in this test you'd place a semi-permeable membrane - the filter - and you'd try to move very small molecules, not viscous, with low or no surface tension, through a filter. is there a fluid that would act as a proxy for a virus? place the fabric, paper, whatever the filter is, in a collander, pour that fluid overtop, see if it makes it through the filter.

if that won't work, then i'd go to work rigging up a test that uses gas instead.

and with that, help, folks! emilio has been making facemasks since, oh, monday or tuesday. 3M has been at it a little longer. i'm pretty sure he'd love to have the brainstorming crowdsourced.

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Dan Empfield
aka Slowman

Saw this on FB, Emilio made the evening news!!

https://www.facebook.com/...s/10223190573017018/

well shi!t howdy! as we say up here in cowboy country.

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Dan Empfield
aka Slowman

I was thinking what to put in the pouch to make it a lot more effective, and I had an idea. What if you went down to Home Depot and got one of those air filters we all put in our homes, the ones that go in the ceiling to trap particles before going to the heat/air? They have different levels, so just get the highest grade one, and then you could cut little squares that fit perfectly in the mask. One big filter would make a ton of that size too, and that is what they are made for, letting air in and trapping particles..

Anyway just a thought, someone can poke some holes in my theory if they have better information..

I don’t see why people are complicating it. This isn’t to give to people in the ICU it’s to give to other people who don’t need the higher protection. Then you can ration the other levels of masks to more high risk groups. No one is saying they should use this in an isolation room.

If you want to debate how the virus transmits etc take it to the Lavender room

Help out Emilo and his employees

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All I Wanted Was A Pepsi, Just One Pepsi

Team Zoot, Team Zoot Mid-Atlantic

The current thinking is that the virus does not survive very long on 'soft' surfaces. 'Hard' surface like door handles appear to pose a much larger risk of transmission. Therefore trapping the virus in/on a mask can be effective in reducing transmission because it means a higher proportion of the virus will die before being transferred into the environment. From rough estimates I have seen even trapping the virus for ~10-20 min on the mask may significantly reduce the transfer of viable virus because they die off so much quicker on soft surfaces. This is not true of all viruses which is why the health advice on masks isn't so clear. However it may be that with COVID-19 masks are specifically useful in reducing transmission and that includes designs like the DeSoto ones without fancy filters.

Hey Dan,


Thanks for your well thought out input. I am trying to find solutions and answers as I have ideas for some other versions. This is all happening while my staff is making the pocket version. Is there a chance that someone on this forum may work at a filtration testing lab? I would be very happy to send masks for testing, especially if we can test possible filter options at the same time, and as long as the testing is of particles much smaller than the .3 micron limit for which the N95 mask is found to be 95% effective.


From my research I have found the Covid-19 Virus is COVID 19 has a diameter of 60–140 nm = .060 - .140 microns According to an article in the Journal of Heat Transfer the average diameter of water droplets in a steam turbine are between 0.2 and 1.0 microns. So on the high end size of the virus is still smaller than the low end of water in the form of steam.


Is there anyone on the forum with the expertise and resources to determine what other substance or element, heated to the point of evaporation, falls between the size range of Covid-19?


PS: If any of my findings are wrong, please correct me.

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Emilio De Soto II
Maker of triathlon clothing, T1 Wetsuits, & Saddle Seat Pads and AXS since 1990
emilio@desotosport.com http://www.desotosport.com

I think what your are describing is a half face respirator.
They work very well but OSHA requires that you be fit tested for use.

First of all, what Emilio is doing here is seriously cool. There's a mask shortage, and he has fabric, machinery, and employees, so he pivoted to supplying the need, helping patients as well as his employees and their families. Well done, my friend.

I have some basic-level knowledge of filtration, both medical and HVAC. I am by not by any means an expert and I don't work in the medical field (or in a testing lab), but I can see from these posts that there are some concepts that might be useful.

The analogy of coffee grounds is used above by dan, and Emilio takes the concept a bit further when he talks about virus size and filter pore size. Since coffee grounds in filters and spaghetti in colanders are part of our everyday experience, it is natural to assume that viruses in surgical masks work the same way, but they don't. At the microscopic level, the viruses entrained in the airflow are very tiny and far apart, and the openings in the filter are huge. Viruses fit through the openings. Particles are trapped in the filter media when they directly impact a filter fiber. Imaging a rock tumbling down a hillside in a meadow. As long as gravity pulls it, it will continue to tumble through the meadow. Now imagine the rock tumbling through a sparse forest. If the rock happens to hit a tree, it stops, even though gravity still exists. If the path of the rock is long enough and the forest is big enough, the rock should eventually hit a tree and stop, even though the openings between trees are large. In the same way, tiny particles are trapped by fibrous filters with large effective pore diameters. Once stopped, particles don't tend to disentangle and continue their journey even though air is still flowing. Emilio's design, with a porous fluffy fabric and using three layers of it, does seem like it has a good chance of being effective. But there is no way to know without testing, so he's on the right track looking for someone in a testing lab.

There is much, much more to it than the above, and I'll add a link to an article below. Regarding testing, there are many parameters including air velocity, humidity, etc, that wouldn't really matter if the entrapment mechanism were pores-smaller-than-particles, but which matter quite a lot when the entrapment mechanism is impingement.

For Emilio and dan, and anyone else who wishes to read further, see:

https://blogs.cdc.gov/...blog/2009/10/14/n95/

for a start.

I am far from an expert, but it's my understanding that viruses do not aerosolize as standalone particles in the air. They attach to water droplets or dust particles. I'm also not sure that using the size of a steam is relevant. The water vapor that people exhale is not anywhere near as "energetic" as steam - I believe it's closer to aerosolized water droplets than true steam.

So trying to beat the N95 filtration size may not be useful. They might have known what they were doing when they picked 0.3 microns.

It might also make it harder to breathe through. I know that really hardcore mil-spec masks have to use canisters to vastly increase the surface area of the filter in order to reduce the pressure required to pull air through. Even some N95's have one-way exhale valves to make it easier to exhale. Which suggests they may be near the limit of what's tolerable.

I'm just guessing here, though.

I just tried ordering 3 masks and my credit card info isn't being accepted. Wish you all the best.

Hello Steve B,

Great information. Thank you very much. To be clear, we are NOT using is not porous fluffy fabric. I do get your point though, and I am seaching through my collection of fabrics, some which are totally impermeable, in order to create my next device.

If you know or anyone reading this know of any testing labs and a contact person, preferably west coast-located, please let me know.

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Emilio De Soto II
Maker of triathlon clothing, T1 Wetsuits, & Saddle Seat Pads and AXS since 1990
emilio@desotosport.com http://www.desotosport.com

My order went through fine yesterday.

thanks for the heads up - ordered 5

Also it isn't necessary to 100% filter out everything. We need to get transmission rates down. Sure it would be nice to get them to zero but what we really need is to get them to below 1.0 (each person infects on average less than one other person). If everyone, meaning 100% of all people, wore even rudimentary masks when they went out in public this would help, even if it's not perfect. As you mentioned earlier, the most important thing is for the asymptomatic but positive people to wear them (and for the symptomatic people to fully quarantine). So yeah we don't need N95 on everyone. N95 are in short supply and also people don't like wearing them (though during the fires I discovered I could easily ride with one if it had the valve). But, if everyone just wore a cloth mask like a bandana, or something like the Desoto mask, when they went out it would help. And cloth masks are easily washed and reused. The fact that we are quarantining and not doing this simple thing yet is a travesty.

I hope they make colors other than white soon! My biggest use is wildfire smoke - but I’d love to have a few on hand. I have one cloth one you can drop a filter into.

I was reading up on diy masks and have found it very interesting that the articles I found from Asia emphasized non-absorbent material while most instructions from the us specify cotton. It makes a lot more sense to me to use non-absorbent material.

From what I’ve read vacuum bags are among the household items that filter the best so you could cut some up.

Just bought 4, two each for my wife and myself. As a cancer patient on chemotherapy, we have to be a bit more concerned than the average people on the street. The DeSoto masks are, in my opinion, better than the paper ones they hand out at the clinic (better coverage, more material between the outside and inner environment), and it won't take much to be more comfortable than a paper mask that gets damp in minutes and proceeds to sticks to the wearer's face for the duration!

Just ordered some for my family.

I ordered a bunch for everyone in our company. You could go to HD or Lowes and cut up a 1" pleated filter to insert in the mask to help with filtration. Standard 1" pleated filters have a MERV 8 rating which is good down to .3 microns. An N95 mask filters down to .1 microns. A merv 11 filter will filter down to .1 microns if you can find one at HD.

i have two. these are comfortable. CO just mandated masks in public and they should be non-medical as they want to make sure the medical masks are in sufficient supply for medical and first responders...Looks like many other states are moving to this, too. these are perfect, comfortable options.

I have ordered 10 masks from desoto for office staff and family

Am an MD in primary care and am running short on surgical masks, and just have a few 95's left. Circumstances over-all beyond belief and description.

n95 is rated to .3 microns as are hepa filters

There are multiple brands of hepa rated vacuum cleaner bags and are available at Home depot and Lowes

My local vacuum cleaner shop is selling individual hepa bags to insert into cloth masks. They are even selling 2 ply cloth masks with an opening between layers to insert a filter.


The desoto solution seems great, 3 ply, comfortable, washable, can insert a hepa filter cut from a vacuum cleaner bag, can easily replace the filter, and the mask form fits. Obviously not the best for icu and direct contact with known symptomatic patients, but offers an option for other circumstances. The way things are going it may be the option for icu...

I ordered some masks and I like this idea of inserting vacuum cleaner filters in the pocket.

my 2 masks got delivered yesterday, thanks desoto

What are your thoughts on the safety of having a HEPA filter that close to your mouth? Is there material (fiberglass, etc??) on a commercial (vacuum, etc) hepa filter that could separate and be inhaled, and be very bad for lungs?