Homemade Masks In A Time Of Shortage

Due to the worldwide pandemic of COVID-19, there has been a huge shortage of N95 masks. [] from Smart Air has been working on designs for a DIY mask that may be able to protect those who haven’t been able to secure their own masks. While there may be an abundance of memes around the various material people have been able to use to substitute for the filters, there is some very real science behind the sorts of materials that can effectively protect us from the virus.

According to a studied performed at Cambridge University during the 2009 H1N1 flu pandemic, while surgical masks perform the best at capturing Bacillus atrophaeus bacteria (0.93-1.25 microns) and Bacteriophage MS virus (0.023 microns), vacuum cleaner bags, and tea towels, and cotton T-shirts were not too far behind. The coronavirus is 0.1-0.2 microns, well within the range for the results of the tests.

As it turns out, cotton homemade masks may be quite effective as alternatives – not to mention reusable. They also found out that double layering the masks didn’t help with improving the protection against viruses. On the other hand, one significant design choice was the breathability of the material. While vacuum cleaner bags may be quite effective at keeping out small particles, they aren’t as comfortable or easy to breathe in as cotton masks.

Have you tried making your own cotton masks? In a time when hospitals are running low on surgical masks, it’s possibly the best option for helping to keep much-needed medical supplies in the hands of those helping at the front line.

[Thanks to pie for the tip!]

528 thoughts on “Homemade Masks In A Time Of Shortage

          1. I donated some to a doc with paper clips in them. He said they are very uncomfortable and hard to shape.
            I switched to the thin red and white wire by the foot from the hardware store. It is covered and bendable. Much more comfortable.

          2. No, a paper clip is not malleable enough. Very difficult to mold around the nose. Bread ties or pipe cleaners are the best. These masks must mold around the nose, to keep the virus particles out. Otherwise, if there is a space between the nose covering and the face, virus particles can get in.

          3. Take a 2” x 2” piece of a tin foil baking dish, fold 4x and then fold over the sharp edges. Run over it with a butter knife or something to flatten

          1. Yes I’ve made over 50 with pipe cleaners. 1 is ok. 2 is better. Sew inside the inside out seam near the nose. Use a wide zig zag and very slowly and carefully zig zag over the wire. I’ve made 50 and still haven’t broken a needle this way. Extra fuzzy pipe cleaners are a little more stable but harder to see where the wire is.

        1. Hi there. I worry about the wire rusting when the mask is washed. For that reason, I have been leaving twist ties/pipe cleaners of the masks I am making. What do you think about this issue. Any advice?

          1. No, don’t do this. Even if the wire rusts, the mask is wearable for at least three cleaning cycles, and this is definitely better than nothing. It’s just an extra step, not difficult, to sew in a bread tie or pipe cleaner segment. if there is a space between the nose covering and the face, virus particles can get in, which kind of defeats the purpose of the mask in the first place.

        2. Floral wire in a bigger gauge (that holds its shape)may work well and not rust like pipe cleaners. Just be sure to make a loop at the ends with long nose pliers so the wire doesn’t poke through the fabric. Probably best to wash my hand so they don’t get mangled in the spin cycle.

        3. Also what works well for the nose bridge: sturdy pipe cleaners (the basic craft type are pretty flimsy), and also what works is lightweight zip ties that have wire on the edges – they really stay put.

      1. you can use bag ties at the top; so that you can pinch seal it. sew them inside in a casing (the seam at the top) . to make the sides fit closer, cut the elastic shorter in length

          1. i am using chenille craft twist , same as pipe cleaners but longer. they are 12 in. long so you can get 2 out of each piece dollar tree ,lg. pkg 100 for $ 1.oo

      2. Yes. True for any mask if your face doesn’t match the Fit Test guidelines. I hear 20% of health care workers don’t pass the fitment because of the shape of the nose or cheekbones, or if a man has a beard – even a stubble. And the best commercial mask won’t fit if you can’t FIND the right size mask for your face.

        So, Home-Bound Mask Sewers; you can hope for a “close” seal with the DIY masks by including pipe-stem cleaners or other conformable wire devices to allow for better individual fit around the bridge of the nose.

        The hospitals I’ve heard from have a secondary consideration for using non-N95 DIY masks – the cloth mask should prevent a non-care worker from contaminating other surfaces, pharmaceuticals, or other individuals with saliva droplets – spittle. Using DIY masks for them spares the N95 masks, if the hospitals can even get them, for the doctors and nurses dealing with the Covid-19 patients.

        Regarding DIY mask materials, I’ve found Paddy Robertson’s industry-expert viewpoint to be interesting (Thanks, Sharon).

        Here’s another Step-By-Step Mask Production Guide from Phoebe Health with info on what materials they use:
        (Surgical Sheets, 50/50 or 60/40 Cotton/Polyester mix) https://www.phoebehealth.com/patients-and-visitors/coronavirus/mask-production

      3. I will be making some using higher end home HVAC filters. The package says they are rated for viruses and they are on the shelf at Lowe’s.
        My wife is a nurse and I’m a mechanic so we both deal with gross people and their gross stuff.

        1. Use VF 6000 shop vac filter by Ridged tools .its 5 layer HEPA . Cut the rubber ends off and use the pleated filter to fold masks. The pleats make it easy to form mask. I made 10 different styles using whatever I can find for ear pieces or straps . HEPA is 100% harder to breathe through than fabric so the hard part is to make the mask fit tight so air won’t leak through the sides.
          You can put rubber bands in the hems use light wire for bridge on put string in the hems and draw tight. Use office staples to fasten I did not sew them the the material is very tough and holds staples well and you can cover the staples with medical tape if you think its needed but I don’t know about heat drying the tape. Also I placed them in 190 degree water and then put in dryer at high heat. The material showed no damage. It’s water resistant material. Use the cheaper filters made out of the white material if you want it’s easer to breath through and costs less but is not HEPA.

          1. Tim,
            Do you know if the VF 6000 has fiberglass in it? I have searched google and Ridge website and cannot find what it’s made from. Thank you so much!

          2. A word of warning to anyone considering using hepa filters as a diy mask! They contain known carcinogenic material!
            They will also not stop a virus transmitting through any mask.

        2. I made a prototype with a HEPA filter but it did not hold up after washing. They can be made but should be clearly marked as disposable. OR make masks with a pocket to insert HEPA liners to be thrown away.

          1. Urgent/ HEPA filters contain fiberglass – almost always! Do not put that in a facemask !! Note: filter products are made from glass fibers, cellulose fibers, polymers or synthetic fibers. This means checking up on each individual type & manufacturer.

          2. If HEPA filters contain such nasty things as glass fibres and carcinogens, why is it OK to use them on a vacuum cleaner in a room where you’re going to breathe the air in anyway? The vacuum cleaner will be pushing the nasties back out into the room in the expelled air.

          1. I clicked on your response and couldnt get it to come up.i was wondering if you could show/tell me what you are using and if they are washable? Any help you can give me would be great. Please stay safe.

        3. dont do this ! i emailed 3m because I 3d printed the montana mask and was going to use the 1500 home filter as a mask filter. 3m has told me theirs is made out of plastic which can get into your lungs if used as a mask. same as using shop vac filters…. its dangerous because of the plastic or fiberglass particles in the bad or filters.

          1. Does anyone know if the danger of fiberglass particles is still an issue if the hepa filter is used as an insert, i.e., there is another material barrier between the nose/mouth and the filter?

          2. Thank you I’ve bought one by 3m and didn’t want to use it until I triple checked .not easy to find even on 3m website which frankly is an obvious question for people with pulmonary issues youd think 3m would be more responsible when choosing material to promote for home air filtering but then I stopped to remember DUPONT and apparently corporate greed always trumps the health and safety if their customers . Shame on 3m

        4. I bought the high end filters to make masks for my daughter who begins her first nursing job as an ER nurse in 2 weeks. After investigating, I came across something that said the furnace filters are made with polypropylene and that is not safe to be breathing in. Did you hear anything about that? I feel like your doomed if you do and your doomed if you don’t. Any input would be appreciated.

          1. “Polypropylene” are the safe ones. It is fiberglass vacuum cleaner filters that MAY be unsafe. (and even that is, according to more recent studies, debatable)
            Remember, furnace filters are, by design, meant to filter breathable air. But make sure you buy the 3M Filtrete 1900 filters which are designed to filter out viruses.

      4. Surgical-type masks do not block virus particles. They are considerably better than nothing as they keep you from touching your face and prevent your sneeze or cough from traveling very far; they are more effective at protecting others than protecting the wearer. If you are sick or carry the virus you can still transmit virus particles through the air a certain distance. When you sneeze or cough not that much exhalation escapes through gaps in the mask. Wiring your mask at the nose does help it stay put but I wouldn’t be too concerned about achieving a perfect seal. Conversely, if your N95 mask is not properly sealed it might not be much more effective at blocking the virus than an ordinary surgical mask.

      5. Iron wire, (bread bag twist ties, paper clips etc.) will rust. Strips cut from aluminum cans or disposable pie plates seem too thin and brittle (they seem to break after bending a few times). Some people have metal allergies to nickle (plated iron items), copper and brass. Look for stainless steel wire online or at a hardware store. Pick the right guage. I happened to have some stainless steel safety lock wire, 0.41″ (1.04 mm) so that’s what I’m using. The best thing I think would be to get 5mm x 1mm flat aluminum wire from craft stores if it’s available.

        1. I have used wrapped floral wire for all masks. Mask is properly removed when I get home, filter removed, mask washed by hand -soap and water and hung outside to dry. I have seen no rust through numerous washings.

    1. Honestly, this is kind of brilliant. The addition of a panel of vacuum cleaner bag as a filter (made by cutting a mask-sized rectangle of the material and sealing the edges) would really up the protective factor. Seriously, I’m actually thinking that we need to communicate this to a larger audience. The medical community is already growing desperate, and we’ve only just begun.

      1. So uhm, to start with, I accidentally reported your comment. Super sorry, hopefully nothing comes of that, I clicked the wrong button.
        Also, I’m looking into making these masks. My mom knows how to sew, and I have EMT friends that are affected by the mask shortages, so… Anyways, I had been thinking of coffee filters, but if vacuum cleaner bags make a superior filter, I’ll see if I can source those.
        We’ve made a few prototypes, and I’ve been thinking of something double-layered with a pocket in the middle that a shaped disposable filter could be placed into, as well as a clipped of bit of paperclip and gorilla tape to serve for shaping near the nose to prevent gaps…
        I also feel pretty sure that if they’re going to be homemade, they could really use a third set of straps, because it’s hard to get the symmetry well enough that you can have a good deal on the sides of the center without a third set of straps so far.
        If there is interest, I’ll let you know what I come up with. My mother is sewing them, and then I’m wearing them for a day or two, providing feedback and drawing designs, etc. We’ve had three iterations so far with some improvement each time.

        1. Business Dragon — there is a post on Facebook — A Taiwanese doctor shared his pattern for a cloth mask with pocket to be able to switch filter material out and wash the rest of the mask. Button Tree (Taiwainese) has the pattern and steps, a woman named Caroline put English translations in the comments so we can follow along! Good luck!

        2. I think it could work and I’m all about it. I’m a nurse and I sew and I have vacuum cleaner bags. I’ve just spent two hours trying to get some n95 masks, there are none within 100 miles. I’d be at work right now if I had one. I’m going to shift gears and start sewing. I’m interested in your prototype designs if you are willing to share.

          1. Please go to Tracey Wilson on Facebook I’m in Catawissa PA to see the masks I’ve made. I sewed a ribbon pocket at the top to put a bag tie in for tightness at the nose area. It can be removed to wash or sanitize the mask. I got the original pattern from http://www.deaconess.com

          2. Interfacing fabric is proving almost as good as N95 masks. I am making them with non woven material that is used in some grocery bags with interfacing on the inside. It has a high filtration rate. Vacuum HEPA liners do not hold up for washing. They should only be used as disposable liners. Email for videos. covid19neighborhoodhelp@gmail.com

          3. If you make them with polypropalene ,and a water proof breathable layer,it will give you more protection. I also ad a felt layer,they are breathable. I also make the pocket.

          1. What about using pee pads for pets. I just sat and breathed through one with no difficulty. They are waterproof on one side. They could be used with a regular face mask if cut the proper size for the mask.

          1. You must contact the company of the bags your using,clothe bags that are hepa by kirby states they have one long finer spun and will not release fiberglass, but each company is different, some are using the inside if paper heps,NO those are unwound fibers,check with the company

          1. I have been making them with iron-on interfacing which seems to be an efficient filter, but I have no way of really knowing how good it is or how small of particles it catches. I plan to keep making them until I run out of interfacing and then try something else. I have also been stitching a double twist tie across the bridge of the nose before I turn it inside-out. That takes care of the gapping around the nose. Just keep on Stitching!

          1. I held a coffee filter around my mouth and nose and breathed suprisingly well. Question is how much it can filter if added as a disposible layer in a homemade mask.

        3. I’m definitely interested! My email is donnacorley43@yahoo.com
          Please email me with what you come up with. I have family who are in the medical field and experiencing major mask shortage, plus our children’s hospital are asking for child size ones also. Thanks to you and your mom!!

        4. The N95 masks are made with non-woven polypropylene material and is .3 microns I believe. I know that landscape weed barrier is non-woven polypropylene but I am not sure how many layers it would take to be .3 microns effective. Just throwing it out there as a possible filter replacement for fabric masks.

        5. Urgent! Fiberglass alert!/ Many vacuum filters & HEPA filters contain fiberglass – almost always! Do not put that in a facemask !! Note: filter products are made from glass fibers, cellulose fibers, polymers or synthetic fibers. This means checking up on each individual type & manufacturer.

        6. COUGHY FILTERS ? LOL excellent idea for an additional layer if natural fiber and no dyes .
          I’m trying a natural cotton panty liners with the plastic side removed and sealing the edges to prevent shedding after I cut them to fit as inserts like other removable facemask filters I’m layering with the goal to be breathable clean natural and disposable in addition to effective as possible for home use .

      2. the vacuum filters may be too heavy to be breathable. I am thinking of using the household filters for HVAC that are virus rated. These can be detached from the encased wire and then cut to shape for a pocket in a simple face mask. My question tho, is it a safe product to use this way?

          1. I found that hard to believe, that they’d put that into your breathing air, even if it wasn’t right over your face. The issue is I believe that between two other media, they have spun fibreglass strands, which are in long pieces and contained by that media. BUT when you start hacking it up, they aren’t. Seems all too easy to fragment the glass fibers and contaminate things with tiny fragments of them.

          2. Latest update is interfacing from sewing shops is best. They are washable. Make sure it is non woven ( woven fibers are arranged in square pattern threads. Example 30 threads run up and down and 30 threads run left to right.)

      3. 3M makes the HEPA vacuum cleaner bags. They also make furnace filters that yield lots of fabric. It comes pleated but is easy to flatten (and then iron it under a pressing cloth). Not sure if it is a savings but you can get lots more filters to slide into the mask.

      4. Respectfully, see this thread on facebook, and the comments on it, from some concerned physicians. Something to work on NOW in parallel to the social distancing. This, combined with mass movement for home-made masks, may help

        Parallel plan to help prevent socio-economic disintegration

        Social distancing strategies will slow coronavirus spread; however, we cannot avoid others forever without consequence. Mutual exchanges of life sustaining goods and services are necessary for the economy and survival. THIS REQUIRES DIRECT HUMAN CONTACT, and we need a PARALLEL strategy to avoid societal collapse.
        I propose we repurpose existing factories to MAKE N95 MASKS that can be worn by most Americans when social distancing is not feasible. N95s effectively filter aerosolized coronavirus droplets coughed into the air preventing its main mode of transmission. IN THE ABSENCE of a government response, see also links below, for MASS GRASS ROOTS EFFORT at making masks, for both health care workers, and for the general public, with numerous web groups surfacing.

        Majority mask use, along with frequent hand washing, will reduce the one thing coronavirus needs to survive, human bodies. Continuous use in necessary social situations could be considered a “vaccine.” Not literally but in the same functional sense. Vaccines prevent viral transmission from an infected host to a healthy one, and masks could accomplish a similar result. Current people with the virus will recover without infecting new hosts. Once the virus runs out of hosts, we win.
        INFECTED PEOPLE SHOULD STILL SOCIALLY ISOLATE. However, non-infected AMERICANS COULD GET BACK TO WORK with a greatly diminished risk of infection. This will ensure the economy produces life-sustaining food, supplies, and services. THIS WILL ALSO ENSURE THAT AMERICANS CAN PUT FOOD ON THE TABLE FOR THEIR FAMILIES, and unlike vaccines or drugs, we can start doing this TODAY.
        WE CAN AFFORD THIS. The president is giving each Americans $1000 for economic stimulus. #30 masks is cheaper and by allowing people to work will be a much better stimulus for the economy. I predict we need 80-100 percent compliance for vaccine-like “herd immunity” through CONTINUOUS N95 use. Let’s flatten the curve without flattening ourselves.

        An additional comment on this (AKA hurricane sandy as example)
        ALSO, we need a mechanism in place NOW for the natural disasters we face in the coming months; hurricanes, floods, tornado’s, earthquakes. Such events (we have seen these yearly) result in short term mass movements of people, from one area to the other, during evacuation and reconstruction. WITHOUT protection, how do we protect these individuals, AND THE AREAS THEY TRAVEL to, from the coronavirus, because their “social distancing” has been disrupted, and the areas they go to also have disruption? Hotels have been shuttered, so where do they go?

        See this link. This, and other articles, have reviewed some of potential benefits of mask wearing
        Why Telling People They Don’t Need Masks backfired



        1. I have used shop vac HEPA filters not vacuum bags and yes you can breathe through them but it’s 100% harder then cloth you need to fit them tight. I have tested them with smoke and smoke will not pass through the filter if it is fit tight or use the white filter it costs way less . It’s easer to breath but is made to filter dust not fine particles or germs. FV 6000 Ridged filter.

        1. Hi Deb, are you having any trouble breathing through the vacuum filter? I’ve heard some people say they can’t, but I’m guessing different filters would be different. I’d REALLY like to connect with someone with the ability to test the effectiveness of different filters and combinations of filters. Like how much better is two layers of polypropylene than one? What about interfacing? Any connections you have? Thank you!

      5. Urgent! Fiberglass alert!/ Many vacuum filters & HEPA filters contain fiberglass – almost always! Do not put that in a facemask !! Note: filter products are made from glass fibers, cellulose fibers, polymers or synthetic fibers. This means checking up on each individual type & manufacturer.

      1. Hi Your style of mask is great this type fits nice znd tight around face and nose im making something very simular. I have been using heavy woven cloth and the four layer of coffee filters. No you cannot put in the washer but folks have been wiping down and airing out. What i do to mine is wipe diwn and i have snd have a microwave we dont use anymore since purchasing a new one i zap it in the micriwave to clean an kill any germs from wearing to get multi use and have it vlean for the next use.

    2. I’ve watched tons of Robert Murray-Smiths videos about graphene and I’ve researched almost every single one. He’s never steered me wrong on any that I can tell. Mr. Murray-Smith has a way you can coat a mask with a copper sollution to make it a bit more Anti-Viral.
      I’m wondering if you could at least take a look at this. If he’s right it could save many lives.

      Oh and here are some papers that back up his claims.



      I would like to know what you think either way. I kind of need to know if he’s full of it, because I plan on using some of his techniques to start my own buisness working with graphene.

      1. Actually, a 2013 study by Cambridge shows that surgical masks are 3X better than a DIY mask at protecting a person and suggests a DIY mask should only be used as a last resort. That said, knowing how complicated it is to make the meltblown fabric used in surgical masks and how hard it is to scale up production (read the great article at NPR.org) we may have reached the “last resort.”

        1. Meltblown Cloth – Original Mask Cloth Material – Nonwoven Filter Fabric Mask Filtering Layer Application- Meltblown Roll Making the Efficiency Filters of Mask

          I read the artticle and ordered this, Do you think it is the right stuff?

    3. There are folks at colleges and universities who are already knowledgeable about materials. They have government supported paychecks. I have read research articles from their labs where they have tested the efficiency of mask material at screening things out of the air, To cut to the chase, why not ask them? We do not have time to dick around. You need to call these folks in government, who are blowing you off in the first place and put the spurs into them for this Plan B to not having enough efficient masks. Also, need to watch the chemicals in the mask, what fibers or other things you are breathing into your lungs. Need readily available material, low cost, efficient, safe to use, etc. 3M is one of those companies that already knows about alternative materials that could be used, but isn’t as far as I know. It forces folks to buy THEIR N-95 masks. Greed rules. They see the problem around them and they just sit back.

    4. This is great and would really be a way to get kids to wear it more. I am working on another model that uses a coated paper clip as the nose piece. if anybody starts doing this just be sure to turn the ends in so it doesn’t poke through. Posting video soon :-)

    5. I’ve been making the ‘pocket masks’ my own design, let me know if you want it. I sew in interfacing, then put pieces of polypropylene inside the pocket. For the best masks I put a piece of merv-13 heater filter. I’d love for someone to comment on the polypropylene. We all have it in our homes and apparently it’s used in n-95 masks. Anyone?

        1. I’m using sew in medium to heavy weight Pellon. I’m leery of using the fusible stuff (glue right by your nose!) But it’d probably be ok. Seems harder to find the sew in these days. The polypropylene I’m using is just cut from those super lightweight shopping bags companies give away all the time. I’ve ordered some Oly Fun fabric, and I’m guessing it’s going to be exactly the same. Meanwhile I’m just pieces out of the bags.

      1. Sure I would like to see and try your pattern. I have been reseraching and buying different fabrics for creating some versions for my friend who is in a student midwife. She told me yesterday that she does not have a mask of PPE and most of the women in her group do not have anything. If you would like to sew an donate masks to their group I would be most appreciative as I have to wait until I get another check to buy more supplies. Thanks Linda I would like to see your patterns and photos.

    6. COVID-19 is 70nm – 90nm. So that makes it .07 microns to .09 microns.
      The .1 micron fabric will catch most of it, but will not be 100% effective.
      But would be just as good as an N95 mask… ie 95% effective.

  1. Hmm. We can all look like a cross between a bank robber and Casper the friendly ghost. Start with a cotton pillow case over your head. Cut out some eyeholes, and put a nylon stocking over that to both hold it firmly in place and act as a pre filter. Sometime 50 years from now kids will see pictures of groups of people dressed like that and it will be as weird as us looking at pictures of people watching 3D movies in the 60’s.

    The lack of all medical disposables has become a serious issue. A doctor friend of mine told me the hospital he works as long ago shuttered the on premises laundry in favor of disposables. In retrospect that may have been a bit short sighted.

  2. Please don’t call this an “N95 mask”! There is a definition for an N95, and it filters out micron sized particles. This is a simple face mask, and can do no more than help keep moisture droplets from leaving the wearer’s face. It might help other people if you are infected with Cov-2; but it’s most effective protective property will be that of “alert, the guy wearing this is sick, I should keep my distance.”

    If you really want an N95 mask, the strong recommendation is “don’t”. You don’t want to deplete the stock that might otherwise go to a doctor, nurse, first responder, or other person who is actually trying to help other people.

    1. ^ I came here to say the same thing.

      By all means call it a disposable or DIY half mask air purifying respirator, but it won’t seal properly and N95 it definitely ain’t.

          1. My brother is an emergency room doctor in the Atlanta area. His hospital is looking for masks due to the current shortage of personal protection equipment (PPE).
            We have spent the entire weekend going through patterns and options for masks that can be sewn at home.

            The link below has the type of mask they are asking for. They do not require the version with filter insert, but did ask for the version with a wire insert for the nasal bridge. They are requesting 100% cotton with a high thread count for effective filtration of viral germs.


            I hope you find this useful in your fight to stay safe.

    2. Well the CDC is now telling healthcare professionals to wear a scarf over their face if they can’t access the proper equipment to treat pts with COVID. I for one appreciate the tips in the graphic. At least it’s more than the CDC is providing.

      1. Thanks for that tip. It allowed me to find this:


        “HCP use of homemade masks:
        In settings where facemasks are not available, HCP might use homemade masks (e.g., bandana, scarf) for care of patients with COVID-19 as a last resort. However, homemade masks are not considered PPE, since their capability to protect HCP is unknown. Caution should be exercised when considering this option. Homemade masks should ideally be used in combination with a face shield that covers the entire front (that extends to the chin or below) and sides of the face.”

        In another table that I’ve seen from an official source, while a mask is better than nothing, without goggles it is not considered even remotely adequate. Cough droplets can get into the eyes, too, and that’s nearly as bad as breathing them.

        The easiest to make contingency PPE I can think of is a T-shirt over the head, tied at the neck, with eye holes cut out just under the size of the goggles. The goggles should even help to keep the eye holes aligned on the face. The T-shirt can be washed in a washing machine with laundry soap after use and the the same soap characteristics that cause grease to be dissolved dissolves parts of this kind of virus, absolutely killing it through disintegration.

        1. I forgot to mention that this would also serve as a hood to keep the droplet borne virus out your hair where if present can contaminate your hand running through your hair, your pillow at night, or in many other ways.

          Also, don’t forget your shoes whose soles can pick up the virus from cough droplets that have hit the floor as they inevitably will There are shoe covers made for painters that are sold in home improvement stores. People weren’t hording those last time I checked. Amazon also sells them. Plastic grocery bags might also be used in a pinch, but care should be taken to make certain they are tight against the shoe soles to avoid, if possible, traction issues.

          1. OMG… are we all going to have to worry about every little thing including shoe soles, money, grocery bags…blah blah blah.. Let’s just retreat into our 5 by 5 card board box, self label it to China, call express delivery for pick up and then kill yourself!! We are all going to die eventually of something so lets just try living a little joy!!

    3. Another thing with mask is “keep my hands away from my face” Corona survives quite long from 4 to 72hours depending on material. Paper – 24h, Copper – 4h, stainless steel and plastic 72h! so if you toucz something then your face you are at risk, mask serves as reminder don’t touch face.

      1. RebelScum, I’m not sure I understand what you mean. Unless people are trained, they cannot help critically ill patients. There are not that many of those trained people. It isn’t a question of valuing one person over another but a question of how those who are trained can help more people. They can’t help if they’re sick or dead.

        1. Susan, thank you for that kind, understanding response. I’ve noticed during this distressing time, an abundance of kindness and compassion with regard to these online discussions .

          We are all experiencing this together, each with our own disposition, concerns and knowledge. Keeping a “cool head” when others need support, will help tremendously when we are on the other side of this. My husband and I are self isolating ( no symptoms) with our two daughters 20 &16. While these girls grew up with this type of mindset, our natural tendency is to get a bit panicky, and, well, there are some hormones in this house!
          To that end, I have been mindfully working at not becoming defensive when someone snaps at me or responds with a less than friendly rant. And I feel better, if we can all lay down our sarcasm, be kind and gracious, take every opportunity to” turn the other cheek” imagine the positive impact we can make!

          No one in this thread has been aggressive, I just thought, based on what I’ve read so far, this group might be open to actively implementing a “pay-it-forward” attitude of compassion and kindness.

      2. Well said since nobody is going to look out for you better than yourself. Most of the people you mentioned are clueless idiots and were absent, high, sleeping in class that day. The onset of my multiple disabilities taught me that real quick back in 2012 and the situation has only gotten worse since then. I still have to fight for the meds and over the counter supplements I need for my survival every month! The people you mention knew that 75% of people with my conditions are dead in 3-5 years anyway and they just wanted me to go away and die and repeatedly told me so to my face. My advice for you people is what you are doing here. Stay informed, stay aware, and educate yourself.

    4. You’re exactly right! Even the N95 mask doesn’t cut it. It does not have an air tight fit like a half or full face respirator. Leave the short supply to the Nurses and Doctors that need them until an abundance are actually available. Remember, even a HEPA filter only filters out 99.975% of air particulate down to .3 microns in size. That’s generally spore and bacterial size particles which are respirable in size. Viruses are usually smaller and requires a lot more protection. SAVE THE T SHIRTS AND KEEP YOU’RE DISTANCE FROM OTHERS, WASH/SANATIZE HANDS AND DON’T TOUCH YOUR FACE.

      1. yes the covid-19 virus is .125 micron in size but what is being protected against is the virus riding on a droplet of water aerosoled from an infected patients mouth. That water droplet is going to be big. Possibly as large as 1-5 microns. Too large to get through a HEPA filter.

  3. A mask seared by a person is like a vacuum filer after sometime. The mask is highly contaminated with bacteria and virus. Just taking it off without contaminating the wear requires proper training, so that the wearer don’t accidentally smear contaminants into his or her eyes, noise, mouth or other surfaces. Now this article suggested, properly washing the mask for reuse. Good luck!

    1. Cotton T-shirts can take washing at 95°C cycle in the washing machine, so getting them clean should be quite easy. William’s link to t-shirt hack seems cool but might be pretty hard to take off without touching the outside.

  4. I wish they had information on particles the actual size of this coronavirus (~0.1-0.2 microns) – they only tested particles 1/10 the size and 5x bigger. There are also an enormous number of other readily available filter materials available that might be worth trying, like HEPA filters and such. A DIY cleanable, reusable mask with disposable filters might be nearly as good as an N95 mask, and certainly a lot better than “nothing” or “hold a t-shirt over your face”.

  5. Someone needs to model a 3D printable filter holder that attaches to 3m masks (the kind with replaceable filters), and takes hepa filters made for robot vacuums.

    The ambitious could add a chamber with some UVC LEDs to kill or weaken anything that gets through the filter.

    1. wanted to do exactly that but withthe bigger and (here) more available round vacuum cleaner hepa filter. Might need to shave my beard off though, currently i use these masks for spraypainting and i always get little fumes in anyways if i have the mask on.
      on a second thought is might just be enough to fill these cheap masks´s detachable active coal filters with fabric?

    2. This is similar to what I have done.
      Buy HEPA rated vacuum cleaner bags, cut them to size and add elastic bands.
      Don’t forget to turn the bags inside out!
      Gave them to some friends who couldn’t get proper masks in time.
      Might post a short how-to if there is interest…


        I live in NYC –

        ALL Our public-facing people are out there with NO MASKS, not even the community masks to protect those around them.

        WE NEED MASKS BAD ASAP – Cheap, easy to make masks for all our grocery store workers, low-wage ppl with no choice but to work if they can, exposed on the front lines.

        Not to mention if we can help our healthcare workers – though the solution for them needs to be URGENT “best of possible” options, not homemade second-best solutions, ASAP.

        But for our shopkeepers, delivery people, people unable to work from home but still working in civil society, our garbage collectors, bus drivers, etc. etc. etc. PLEASE GIVE US INFO on how to

        MAKE CHEAP MASKS that protect the wearer and are “better than nothing” so that we can share these with all of the front-line workers who are not healthcare.

        I don’t know what the deal is with our prisons, but certainly our corrections officers, etc, etc etc

        WE NEEDS MASKS BAD here in our populous dense citys.

        Thanks in advance, be expecting to hear from y’all not just on this nice lil blog but on all your socials. (is that what marketing’s calling them this week? Please get ur kids to TikTok them how to’s, or I hear they let ppl over 16 on TikTok so maybe you wanna TikTok that diy and send Buzzfeed the quick how-to

        AGAIN, Thanking you in advance,


      2. Hay has anyone tried taking a HEPA filter for a furnace apart and using the paper on the inside for a mask !! It should sew ok , I’m not sure how many microns it would filter but it might be something!?
        Or maybe tyvek!??

        1. I have a friend who is making masks out of HEPA furnace filters. He is a leading aeronautical engineer, so I assume he is working based on facts.

          I would not expect Tyvek to be a suitable material as it does not breathe well enough.

          1. I sent an email to Fitrete to ask about using the filters and here’s their response:

            Thank you for contacting 3M, Construction & Home Improvement Markets Division.

            These filters are designed to be used in HVAC systems only and are not suitable substitutes for alternative uses. Altering any of our 3M Filtrete™ Filters is not recommended and strongly discouraged. Using the filter in any alternative manner would not be supported by 3M.

            For information on the Coronavirus and recommended protection products, please consult the CDC .

            If you need any further assistance, please feel free to contact us directly at 1-800-388-3458. We are available Monday through Friday from 8:00 – 5:00 CT.

            In the event that you need to call, please mention this email and reference #(14343033) so that we may access the file that has been created under your name/email address.

            We appreciate your interest in 3M pr oducts!


            3M Product Application Support
            Construction & Home Improvement Markets Division

            – If there is a need to reply to this response, please leave the subject line intact to assure correct routing. –

            |———–Original Message Follows————|

            Subject = Filtrete(TM) brand Inquiry

            Message = Are your filters safe to use in homemade masks? A lot of people are using them and I want to ensure they are safe to breathe through since that was not the intended use.

        2. This is a thorough and scientific explanation how to make an actual N95 from a furnace filter. One filter should be able to make many. Using cloth or coffee filters or paper towels is utterly useless – you will have a false sense of security. All this reckless misinformation underscores the need for basic science education for everyone.


  6. “According to a studied performed at Cambridge University during the 2009 H1N1 flu pandemic, while surgical masks perform the best at capturing Bacillus atrophaeus bacteria (0.93-1.25 microns) and Bacteriophage MS virus (0.023 microns), vacuum cleaner bags, tea towels, and cotton T-shirts were not too far behind.”

    Am I the only one that looks at the article and says “T-shirts allow 3-10 times the number of particles through, how is this ‘not too far behind’?”

    1. Also avoid falling victim to “hot particle theory” type of thinking.

      This misconception is exemplified by the nuclear scare propaganda where ingesting one microscopic “hot particle” will absolutely assuredly give you cancer – it’s just a matter of time. According to this type of thinking, no protective measure that isn’t 100% effective is actually worth anything.

      As applied to viruses, the misconception takes the form that if you ingest even one micro droplet containing the virus, you get sick, so a filter that filters 50% or even 95% does nothing for you. One gets through and that’s it. In reality the immune system gets rid of the offender and you need a bunch to overload it to the point of getting infected.

      1. Sir, you deserve a medal. I have preached this for such a long time. You would probably be shocked to learn about all the different germs and viruses that are in your system right now. The thing is–your body has it under control.

        1. The problem though is that this is a NOVEL virus, it’s new to us, the body doesn’t know to attack it because it jumped from animal to human. I would think any protection is better than none.

      2. 100% this. Preventing as much as possible is a good thing, but stopping it all is a wasted effort.
        People would be surprised by what goes on in their bodies all the time.
        Hell, every person reading this page right now has had cancerous cells in their body but the immune system dealt with them. Probably almost everyone over the age of 5, in fact. (averages)
        This issue is becoming more known because better cancer detection tests are picking up totally harmless clusters of cells that the immune system can deal with easily, causing unnecessary panic and surgery. It’s a really big issue.
        You really need large numbers of infectious cells to get a proper foothold. Not all the time, but most of the time. In this case, this virus isn’t particularly effective at invading.
        There’s also the fact that everyone is probably sitting in a room with something radioactive, including likely their own body if they like particular common foods (like bananas).
        This whole panic buying is evidence of this, that people freak out to dangerous extents instead of thinking with their heads and listening to people in much better positions than them.
        Equally, if you were to actually seriously attempt to block every infectious agent invading your body, you’d probably die rather painfully. The immune system itself is moderated by active infection, without it the body freaks out hardcore and ramps up the sensitivity until it starts seeing your own body as invasive! I know this fact personally, auto-immune is no fun. Overly-sterile environments are unhealthy since it isn’t natural, no living organism on the planet has experienced it for any significant length of time for it to matter, or for them to evolve with it in mind. (at least none I know of, maybe some weird extremophiles have)
        To put it all in to perspective, there’s an absolute load of infectious cells flying around in the air all the time, and spores, pollution, radioactive compounds, etc. Quite hard to avoid it, outside of the driest areas of the planet.

    2. I don’t like that “cotton T-shirts” was left with such a wide open definition. They are available in a wide variety of weights from almost sheer to heavyweight. The study did note that the heavier fabrics (like tea towels) had higher pressure differentials (meaning they were harder to breathe through) and surmised that the more uncomfortable they were, the less likely they would be worn. But I have no idea which T-shirts they tested.

      Probably more importantly though are the study’s conclusions that seem to be overlooked by the people offering all the different solutions here: “…these masks would provide the wearers little protection from microorganisms from others persons who are infected with respiratory diseases. As a result, we would not recommend the use of homemade face masks as a method of reducing transmission of infection from aerosols.” So their best answer is essentially “they might help a little bit, but don’t count on it.”

    3. I saw a couple of articles that ranked the tea towels and vacuum cleaner bags high. But in one, they rated the t-shirt as a better option because of breathability. They recommend two layers which would improve its protection, I would guess. Or use t-shirt as lining (softer) and quilt-type cotton fabric for other layer. Anything is better than nothing.

    4. No you are not the only one. It is so important to do what we can to not spread misleading information. Here is data that shows the n95 at 95% multiple items in between and tshirts at 50%. And look at all the people talking about tshirt projects. How many are doing that because this guy said something little better than half as effective was “not far behind” quit a few I would bet

    1. The best-performing fabric item against 120nm particles (the size of the ncov-2019 virus) is a Walmart scarf, but that still allows 50-60% penetration.

      What I find surprising is that the Walmart scarf does better against smaller particles, getting down to about 10% (plus error bar) for 20nm diameter particles. I would have expected it to do better against larger particles, but perhaps larger particles have enough momentum to get through the fabric, with the small particles getting caught.

      1. Google for most penetrating particles size. There are different filtration mechanisms for micro- and nanometer-scale particles. In between there is a filtration efficiency minimum (usually around 200-300 nm, but it depends on process conditions).

    2. Why aren’t people buying air handler filters? Like the ones for your house intake vent. The price may be high but there is enough material and filtration to make a few masks. You just have to cut it to size and pull the metal mesh out. You might even be able to use it as a frame if you are clever with it.

      1. Corona infects you through your mouth, nose and eyes. So it seems that your asshole is quite a safe place. I conclude that the bacteria in the stains are effective Corona virus fighters.

        I would vote for wearing your underwear stained-side in. Because your breath will keep the stains nice and moist, allowing the bacteria to do their best job at fighting the Corona virus.

        1. Actually the virus also exist in the faecel matter of those affected.


          >The professor said it was possible the coronavirus might be transmitted via faeces. After entering the intestine and multiplying, it may then be excreted and come into contact with a person’s hands, he said.
          >He also warned that the virus could be turned to vapour by the force of a toilet flushing, endangering people in the same room.

      2. On a more serious note: the bacteria from the stains are harmless to you yourself. Because they come from you yourself, and you are already full of them. Can’t infect yourself any more than you already am.

        Wearing somebody else’s stained underwear, of course, changes the whole picture…

        1. Bacteria from the lower GI tract (small and large intestines) in the upper GI tract (mouth, sinusses, esophagus, stomach) = bad times. It’s a myth your own gut bacteria wouldn’t be able to make you sick! Shit is shit. It’s best to avoid ingesting any of it!

  7. Going on how well (badly) they block light, hell no, that looks like it wouldn’t block the largest amoebas never mind virii, you can see the holes. I know it’s mostly to defend against droplets, but still would not take a very fine spray to cruise straight through.

    Got a generic surgical mask here, and going by what at least blocks light as well, a doubled over Kleenex is looking pretty good. However, they are delicate. Off the cuff improv of what is to hand, got a large pocket handkerchief, but a bandanna would work, double the Kleenex, lie it with one edge aligning to a diagonal, fold one point in over it, then fold it across the diagonal, then the next point over the top. You have now got 2 layers cotton, 2 layers Kleenex, 2 layers cotton, and can tie the points behind your head. Beware of air ingress around the nose (Stuff cotton balls in there if nothing else works???) Mark which side of the bandanna/handkerchief is which so you can change Kleenex sheets often and keep the same inside and outside orientation of the mask. I would imagine much dampness from hard breathing or prolonged use would deteriorate the Kleenex.

    Possibly a 3D printed mask with good mesh support of a half or quarter folded sheet of Kleenex might be a good idea.

    Be aware also that Kleenex tends to come quite dusty with loose fibers, you might wanna give it a shake before breathing through it. Also don’t know how much paper fiber you’d clog your lungs with long term. Possibly the bandanna/handkerchief would help this issue a little.

        1. Grabbed one, it’s actually pretty easy to breathe through… too easy. See too much through it too… and I recall trying to use kleenex for coffee when we ran out once and that blocked up and the pot overflowed, so I assume there’s more getting through a coffee filter, but if you wanna try “defense in depth” then I guess you could layer with other stuff. Or staple kleenex between two of them to protect that better or something. It looks about mid way between cotton cloth and kleenex.

          1. IIRC Electrostatic filters have a big problem with charging up the particles. Everything they don’t catch is charged and wants to deposit on something even more.

            Probably great for cleaning rooms that are only used by one person at a time with a long gap in between though.

          2. I was referring to generic basket filters, for 12 cup machines, the pleated ones that flatten out into a circle. I think the cone filters, particularly brand name like melitta, might be denser. Denser still would be those small circular ones used in espresso machines I think.

          3. Maybe the basket kinds of coffee filters as I have would be suitable for salt deposition/treating as in the materials by spiritplumber below, since they maintain wet strength.

            However, there’s still the problem of finding a way to use them that doesn’t require you to already have a properly fitted re-usable mask.

          1. I, too, want to know about this! Was looking for the standard medical grade filter fabric (melt-blown non-woven materials) and there are no retailers stateside. Wondering how this material compares to interfacing and if interfacing would also filter particles.

          2. Looking for further comments on interfacing if anyone gets info from additional research. I assume that iron-on interfacing would not be desirable doe the a chemical coating?

            Alternatively, more thoughts a quilt batting square as a removable insert for added filtration? Bamboo vs. cotton vs. polyester? Trying to imagine how they compare/contrast in terms of allowing breathability and ensuring the batting isn’t infused with a chemical that one wouldn’t want to breath in.

            My first pass will be using a cutout from a C/Q vacuum cleaner bags as an insert. The ones I ordered purportedly filter to .3 microns and are cloth – hoping that they will be easier to breath through than a papery one. Found bendable jewelry wire from Michael for the nose bridge, since even several twist ties together didn’t seem to have the strength to hold a shape when pinched.

      1. I have been try to find out if the online calls for masks have any specific requirements that I can use as a guide. It seems like the articles I’ve read are referring more to surgical masks that can be used as a cover to lengthen the life of the N95s or the can be used in less dangerous situations.
        There is one group in Massachusetts and one group on the west coast. I can’t seem to get a direct response, just a form to fill out. I would prefer to get the masks to local health service providers. (Colorado, for me), but would like to know if there are preferences/requirements for the donated masks first.

        1. I am in the St.Louis area and just reached out to a local friend who is an EMT. I asked her to find out if 1) they needed/wanted homemade masks and 2) what specifications. She came back with a resounding yes from all of her staff. They are requesting I simply make a mask to snuggly cover their N95 masks so they can prolong the use of them. Two per person so they can sterilize one in the event of back to back calls. I am making them with a filtration pocket in the event they have no other choice.

        1. Hi-
          I think about anything is better than nothing.
          I am going to try making a few with thicker interfacing, probably not the stiff stuff, just to see breathability. I am not trying for N95 filtration. Just something that could extend the life of the N95s or for less dangerous situations.
          What I am also considering is that none of us are making these in a sterile environment. While I plan to wash any I give to someone, the recipient may also want the ability to wash it. That is possible with interfacing, but not with most of the filters described.

    1. I’ve been making masks with the oly-fun polypropelene crafting fabric you can get at walmart/hobbylobby/joann’s.. it’s breathable and made from POLYPROPELENE.. the same kind of nonwoven fabric the surgical masks and n95 masks are essentially made from.. I’ve been using cotton/polypropelene/cotton as a sandwich together.

      1. I am also using Oly Fun. It’s 65 gsm, non woven, polypropylene material. I read that surgical masks are made with three layers of 25 gsm non woven fabric, so it seems closer to what should be used. Very breathable, sandwiched in between two layers of a high fiber/sq/in fabric. I was wondering if two layers of OlyFun on its own, without the fabric, would be just as good or better. Would take a Lot less time to make them.

  8. N95 is a specific rating indicated how well a properly fitted mask will block small particles and microbes, which a t-shirt and a pillowcase won’t even remotely approach. Holy ^%&# what an irresponsible post.

  9. I am pretty sure it is non woven interfacing. Both are made of polypropylene. I am just not sure how to determine the right filtration. For sewing/fabric uses, the stiffness is usually how it is rated.

  10. Oddly enough, nothing I’ve read to date says even a surgical etc mask offered much in the way of protection. That included healthcare workplace ones. Epic treaties on Hand Washing OTOH….

    1. N95 medical-rated masks filter particles of the appropriate size and also protect against fluid intrusion (such as a spurt of arterial blood hitting your mask) to a certain degree.

      The “surgical masks” we usually think of, the flimsy paper/fabric things are something else entirely.

    2. Assuming there’s a direct correspondence between dose and chance of catching it, pretty much any one of those masks are going to make a major difference. Reducing 50% of transmission would go a long way towards stopping an outbreak since the transmission rate is only 2.5 from what I hear.

      The problem with masks is that we’re all better off if the healthcare workers have access to them, plus they make people feel safe and think it’s fine to go outside.

    3. There seems to be evidence that common table salt can at least kill the virus on a mask’s surface – a common reinfection risk. A patent has been issued on this, but no production yet, as far as I know. Even a bandanna soaked in about 1/3 salt solution with a drop of dishwashing liquid may improve common surgical masks: PATENT https://www.nature.com/articles/srep39956. If there are any chemists out there, they can interpret better. A lay interpretation is in businessweek: https://www.businessinsider.com/mask-coated-in-salt-neutralizes-viruses-like-coronavirus-2020-2.

      1. Quoted from the businessinsider article: ” Experts say that for most people outside of Wuhan, China, face masks are unlikely to protect you from the current coronavirus outbreak, for example. ” Why does the media keep repeating this? It’s wrong and so frustrating.

  11. Here in Vietnam, most people are wearing masks and staying at home. N95 respirators were not available, only N90, and most people are using unrated random masks. The first thing we did at home was develop a procedure to disinfect the masks on coming home (chloroxylenol solution) so we don’t create a mess of waste or accidentally make things worse for ourselves.

    Really the masks are good at social signalling. If you see someone not wearing a mask, then there’s probably other precautions they don’t take, and it’s best to keep a distance. I’ve done a quick test of this by looking out my window and counting whether motorbike drivers that don’t wear masks are more likely to also not be wearing helmets. I’m not sure if this effect applies in the West as well!

    TLDR, cabin fever is setting in and I’m passing the time by counting things.

    1. No, in the west, mask wearing (outside of professionals and East Asian students) is mainly associated with panic buying, paranoia, and a disregard for actual effective safety measures like hand washing with soap and water.

      1. Since the very beginning of the outbreak, when nothing was known about this particular virus and its transmission routes, hand washing has been touted as “effective”

        Where’s the actual study that shows this to be true ?

        Would you happily board a crowded commuter train with infected people talking and coughing, as long as you could wash your hands with soap and water when you got home ?

  12. These are not N95s and Hackaday is really starting to border on outright misinformation during a state of emergency. Please, PLEASE curate these articles a little better. This doesn’t even mention coatings, or positive pressure, or anything else that is going to make them into anything other than a permeable fluid barrier. Do not put N95 in the title.

    1. Absolutely agree. If this mask is not officially tested and rated as N95 then it is NOT an N95.
      HaD I love you and have been reading you for 20 years, but you should know better!

  13. If you check on the WHO site, even surgical masks are somewhat effective. The reason we are even having these conversations is because the government and businesses lost interest in maintaining pandemic level supplies of masks. Compare the pictures of South Korea and Italy and tell me that masks don’t help.

    1. I’ll not tell you that however I will tell you that you haven’t given anything supporting that they do. The important differences in the response in these two countries aren’t the availability of masks and the severity of infections aren’t helped by them.

    2. If you are looking at south Korea, and coming to a determination that what they are doing isn’t helping, then you are looking at south Korea wrong.

      In the US the number of confirmed cases is doubling ever 4 days, in south Korea they are at 18 days, and the trend is for that number to keep going up.

      Right now, the data suggests that was ever south korea is doing is what we should all be doing (from a spread of virus stand point)

  14. There is an initiative to do DIY masks in the Providence system in Washington. Their website is just up this evening (3/18) and as I understand their plans, they will be posting a video on how to construct masks. For more information go to http://www.providence.org. Given the people putting this in place the information is trustworthy.

  15. First I want to say:

    Please remember that you are a human being. If you have hoarded certified masks and you are _not_ part of the high risk group, donate them to high risk people!

    – People that work with infected patients (medical, police, firefighters and store clerks!)
    – People that are high risk people (depressed immune system, bad ventilation, etc..)

    This impromtu mask:
    I have to say that this is really misleading, because it seems they did not understand, why medical personell needs to wear a FFP3/N95 mask.

    However! Such an impromtu mask will work to a certain extent, because it reduces the chance of getting infected.
    Such a mask is also a viable approach to protect others in case of being infected, because the aerosol is caught.

    It is a last hope solution in case of an emergency, because it is better than nothing.

    “The virus size does not really matter”
    a.) because a Covid-19 needs to be bound to a droplet of water to stay infectious – this matters!
    – if it dries out the virus hull will crack and render it inert
    (Distance 1-2m helps)

    b.) you need to ingest a certain amount of the virus to get infected
    For people with decreased immune systems this amount is naturally lower!

    – highest chance: new aerosol in the air from an infected person
    – when the droplets dry out, the virus will die
    – during the drying the infectious virus amount will decrease over time

    Also it seems that the lighter cases have infections contained in the upper respiratory tract, while the severe cases have them in the lung. So one can speculate that slowing down the inhaled droplet will also reduce the chance to turn into a severe case.

    – the mask will act as a barrier against putting your smear contaminated hand near your mouth and nose

    1. +1 for this.
      -1 for the misleading title of the article.

      I paste my comment on a HaD article from 12/02/2020:

      “Coronaviruses are mainly transmitted by large respiratory droplets and direct or indirect contact with infected secretions. They have also been detected in blood, faeces and urine and, under certain circumstances, airborne transmission is thought to have occurred from aerosolised respiratory secretions and faecal material.” – UK official guide

      “Published data have suggested that sneezing may produce as many as 40 000 droplets between 0.5–12 μm in diameter […] whereas coughing may produce up to 3000 droplet nuclei, about the same number as talking for five minutes.
      “[…] found that, under normal air conditions, droplets smaller than 100 μm in diameter would completely dry out before falling approximately 2 m to the ground” – https://www.ncbi.nlm.nih.gov/books/NBK143281/

      I recommend to take a look at the falling curve in the article above… it shows, droplets in room temp smaller than 100μm dry out pretty fast, so smaller than 2,5 dry out very fast.

      Question remain: how long the dried out small particulate circulate, how long are the viruses yet virulent when dried out – some studies suggest longer periods on some surfaces incl paper, whereas this domain is well handled by thorough and often hand washing.

      Such a DIY physical barrier worn seems for me to do the trick very well to:

      1. filter out the droplets by coughing / sneezing when worn by an infected (who should strict STAY AT HOME, no excl.)
      2. filter the resp droplets to protect healthy (who sould also stay at home and reduce social contacts by all means).

      Maybe a scarf itself is also better at handling versus any mask… you grab a scarf somewhere and with a good technique you can unfold w/o touching the face, whereas there are no means to take off a mask w/o touching your head at least somewhere by the straps.

      1. I also wonder, to what extent practically ANY kind of face covering helps to reduce the chance of infection, merely by raising the temperature of the airway. As I hear it, covid-19 prefers a temp of 26C for maximum replication. If you bundle up your face and raise your airway temp, you’re slowing it down, therefore for a small amount of virii getting in your nose, your immune system may be able to deal with it, if it’s slowed down sufficiently. Meaning if someone infected sneezes straight into your face, and then you put a mask on right away, it might even reduce chance of you getting it still.

      2. When you take mask off do so with gloved hands..paper towel or tissues..put mask in a isolated place .. throw away tissue/paper towels used without touching take a clean tissue to take off gloves throw away then immediately wash hands.. should offer some protection if one needs to go out ..

  16. Breathing through a pile of pillow or t-shirt doesn’t really work though,
    It is like when the kid is hiding from bed monsters under her blankets
    and the air pocket gets stale.
    There is a reason for the one way valve on a N95, it lets you blow off
    the CO2 through the valve but you suck fresh air through the filter.

    N95 masking is super important fr TB and other aerosol spread pathogens, the caveat being you actually bother to do the banana oil leak test fitting so the aerosol doesn’t just take the shortcut around the gaps in the mask, but we don’t see much mention of wearing glasses or goggles too.
    Back in my Firefighter-Parmaedic days a guy on our rescue got blasted with puke in the face by some homeless-drug user guy with the ABSs of chronic infections.
    They did the gamut of tests, I think he was fine though had to take HIV meds for a few months; but at the debrief the doc said that while there are plenty of lymph nodes filtering blood from the septic tank which is our mouth, the mucous membranes around eyes are much more sensitive to bringing in infections.

      1. For future reference you generally don’t want to use CC’s noncommercial clause for any project you intend to be shared and improved upon. I’ve generally seen it used on works of art where the artist doesn’t want to control distribution but doesn’t want other people selling it, “open source” projects where the creator intends to make a buck off of it, and people who don’t understand the license.
        It is a poorly understood clause best kept away from open source projects or anything you want used to help people.
        The sharealike clause isn’t nearly as problematic. It makes CC a typical copyleft license. As applied to a hardware project, it does exactly what you want a copyleft license to do: require people to share their improvements and modifications freely. It’s not appropriate for every project, but often desirable on an open source hardware project.

        1. Thanks! It’s mostly there because a Russian guy started selling bootlegs of my laser cutter on ebay, then claimed he could because I didn’t have that in there. Fortunately he was inattentive enough to label them “Made in USA” even though he was making them in Smolensk….

  17. Mask sealing issues. Just running this one up the flagpole, salt dough? Salt dough is easily made from flour, water and salt. The salt should kill virii on it after time, but you should probably discard as often as you change mask. As dogs and small animals are dumb enough to eat too much of it if they get to it, and give themselves salt poisoning, it should be discarded responsibly, don’t go dropping it all over the sidewalks.

    Idea would be, with non-conforming mask types, to mix up a consistency which maintains shape well and put a glob over and around your nose, to block the gaps between your nose and the mask. This may also stop the misting glasses/googles problem on exhale. Then one can carry a small container of it around in your pocket for re-application. Should stay soft a long while, especially in a sealed container. One might have to press it into the top of the mask somewhat to keep it in place.

  18. Mask sealing issues, just running this up the flagpole, salt dough? It’s easily made and should remain sterile, can conform it to the contours that the mask won’t.

  19. Why are some western governments (I’m in the UK) telling people that N95/FFP3 and other face masks are not effective (or using some vague statements like they are ‘not 100% sure that they are effective’)? If the virus particles are significantly transmitted in airborne water droplets, and the mask can stop people breathing these in (or coughing them out), why are we not all wearing them?

    1. I think because they want to secure all the masks possible for the people that is in most need of one (nurses, doctors, infected, etc) because they did not have enough reserves to start with and there is a surging global demand.
      This bothers me as well, cannot stand doublethinking even if it is for a good cause.

      1. Thje supply problem is further up the supply chain and not at the retail store level. Hospitals are not buying their face masks at local stores. I have read that some suppliers are now stopping shipments to stores so that all their masks go to hospitals and other health care providers. People can make their own. Masks are partially effective and should be used to prevent the spread of the virus, especially since asymptomatic “carriers” are now known to infect people.

  20. Someone is looking to be sued. viruses are so microscopic, they have smaller than bacteria by a factor of anywhere between 3-5 times smaller. That a shirt or pillow looks like chicken fencing to these viruses. How was this t-shirt tested to be N95 rated?? it wasn’t.

  21. Sheet straps / bed sheet corner holders / blanket straps … of the short, cross corner type may be useful for holding improvised masks or for improving fit or security of other masks. I have seen them in Dollar Trees before, not sure if that’s a current item though.

  22. Be careful with HEPA filters they often contain borosilicate which isn’t supposed to come out of the filter but quality can vary and some manufacturers are better than others. You don’t want to inhale glass like particles.

    A better alternative for material is water filters. If someone can rig up the tube type respirator where you breathe through a canister or pack then there are already water filters that filter down to .2 micron, the virus is .3 micron . The ability to breathe through the filters is also very easy because of the surface area and I would assume the larger area would lead to longer service life before discard is needed.

    A quick air filter:
    whole house water filter or under sink filter with .2 micron filter installed. Pipe to this inlet and outlet for breathing tubes. No need to fabricate anything but fittings.

  23. What does anyone think of that non-woven polypropylene material that is commonly used to make recycled and reusable shopping bags? It seems to have much finer holes than typical t-shirt material, the large pores in it aren’t the hole size. It is available made into many cheap items in the dollar/pound type stores. I’ve seen large sheets of it sold as a landscape mulching cover sheet, and other larger items are dust covers and some drop sheets.

    Anyway, it’s fairly absorbent, which I think is what helps dehydrate droplets quick, though not as much so as cottons and papers. Not sure what it survives in the way of cleaning/sterilisation for re-use though, it might just maintain shape at the 70C mark in an oven as is recommended for the surgical mask types, but could stick to hot spots, boiling it might deform it. I think it should survive a 60C hot wash with laundry detergent and bleach though.

    1. I have been researching materials that are sufficient for protective masks. Many articles I’ve read mention non-woven materials and polypropylene material as well. My 68 year old Mother who was a cosmetologist her whole life needed shoulder replacement surgery and was unable to return to her profession. She now works in a grocery store and deals directly with the public. I worry about her well being because even “sick/infected” people need groceries and she would have no clue if they were sick. I NEED to make her some masks to wear at work to give her SOME kind of protection. I do realize that our medical personnel are 1st in line, but they are not the ONLY ones who deal with this virus head on.

      I found a few ads on Amazon and was wondering what you may think of using these materials?


      Please let me know if this may be something good to use or would it be a waste of money? Thank you. :)

    2. im using this.. it’s called oly fun… washing in cold water and air drying.. my masks have cotton/poly/cotton.. breathable and similar resistence to my n95s..

    3. Oly Fun fabric is similar to what those bags are made of. It’s 65gsm, non woven polypropylene. It’s water resistant. You can put water on it and it won’t go through. I’d think you wouldn’t want anything absorbent? I’m making masks using one layer of oly fun between two,layers of cotton so as to absorb moisture from your own breathing. I e read that surgical masks are made from three layers of 25 gsm non woven polypropylene fabric. I’m sure the three layers prevent more from getting through, though these should work for friends and family, as well as hospital use if nothing else is available.

  24. Was thinking. How about “doggie pee pads”? Can that material be cut and shaped into a small face mask? Some are “anti-bacterial” and have a plastic shield on one side , with cloth like material on the other side. Also, how about Ladies’ cotton bra cups? (Not trying to be funny at all, but could those be cut and re-sewn in such a way to work like the other type of face masks that are used in tool shops, etc. (Just some ideas, really not sure if any of that would work well, but, in my view, it’s better than nothing. Right? (Plus, many say you should only wear a “mask” if you are sick or infected. Well, what about the fact that medical experts are saying that some people “don’t know they have Covid-19 because they have no symptoms? So, should we be doing like all those Asian Countries that have EVERYONE wear a mask? Because some may have the virus and not know?

  25. Has anyone tested simple electrostatic face masks? They’d be very easy to make: take a piece of tulle (tulle is a very open nylon mesh fabric/netting; used for things like wedding veils) and sew it into a surgical-mask-shaped bag, then fill it to a 5-10mm thickness with Styrofoam pellets. Styrofoam beads are highly charged, and readily attract small particulates (and everything else). As long as it’s not crushed, the gaps between pellets should be open enough to breathe through, making it more comfortable than a mechanical filter. Perfect seals around the edges should not be as important, as any leaking air would still run past a cm or two of pellets in the gap.

    The first problem I see is that tulle is stiff and scratchy. For comfort (and additional filtration), the face side of the mask might be made of a lightweight cotton knit (T-shirt), while the outer side of the mask could be tulle. Plus the bulkiness of the pouch might be uncomfortable – I’ve not created one myself yet to try.

    Pellets are ultra cheap so they could be discarded and replaced whenever needed – an old bean-bag chair would probably supply a family for a year. Otherwise they could be recharged by soaking them in salt brine and rinsing thoroughly.

  26. Im confused. The grahp refers to testing or blocking .02 micron size particles and the article says the virus is .1 to .2 microns.
    Is the .02 on the graph a typo and should say .2? If it really is .02 then most of those materials would seem fine for .1-.2 micron?

  27. I work in grocery retail…I have experienced the last four weeks like I have never seen in the last 30 years. I have seen complete hazmat outfits so customers could purchase flowers and chocolates to the sad little old man wearing a hand tied bandana just so he could get a loaf of bread and some canned fruit. Many customers are taking their children with them to the grocery store because either they cant leave them at home or are taking them because they are bored and want to go. Personally I sew as a hobby and any type of DIY mask is going to be better than what I witness day in and day out. Winter scarves, nasty dirty used masks, t-shirts…I will make DIY masks and if they help they help. If all else fails mind of matter will make a difference. Armchair experts…do something and make a difference!

  28. Nobody mentioned this it seems:

    How about multiple layers of relatively poor mask material like cotton T-shirt?
    Extra wrappings should be more effective, while still allowing air to get through.

  29. so from what i can tell from my googling so far is that CoV2 is about .4 to .2 microns. just a thought: off the shelf blue ray etch at about .1 to .15 micron.
    Any thoughts on materials that would make for a good or decent substrate to etch pours into?
    i’m sure there a lot of problems with the idea but with little else to do and a desire to do something i put it out there.

  30. Here’s an article from Tennessee about the man who designed the medical masks and spent 30 years perfecting them. His advice is for the general public to use DIY masks and leave the true N95’s for healthcare workers, and wash your hands….


    I’m trying to find ways to get more masks to hospitals, my son is a resident at Temple Hospital in Philadelphia and they are in short supply of needed PPE. If anyone can help me find a reliable source of medical grade melt-blown fabric, I can get my sewing machine fired up and running!!! Thanks if you can help!

  31. So surgical masks are made from non woven polypropylene….. Resuseable shopping bags…. Made from non woven polypropylene….. Is it fair to say I could pit some resuseable shopping bag material in my mask as a filter?

  32. Hackaday should remove this post.

    There is so many totally stupid non science based “life hacks” swarming the internet – and this is one of them.

    “designs for a DIY mask that may be able to protect”…

    No a mask will either work or not.

      1. Did you actually read the conclusion of the referenced article?

        “However, these mask swould provide the wearers little protection from microorgan-isms from others persons who are infected with respiratory diseases. As a result, we would not recommend the use ofhomemade face masks as a method of reducing transmissionof infection from aerosol”

        1. I don’t think you did

          It says
          Our findings suggest that a homemade mask should only be considered as a last resort toprevent droplet transmission from infected individuals, but it would be better than no protection.

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