Homemade HEPA Filter Mask Instructions (Using HEPA Vacuum Bag)

As I write this, the coronavirus pandemic is getting exponentially more widespread every day.

Emergency food is getting scarce, and in an effort to protect themselves from the virus, everyone wants a face mask, especially an N95 respirator, which is said to provide the best protection against getting sick.

The problem is that N95 respirators are now impossible to find. Read more about N95 Masks.

Luckily, it is possible to make your own respirator. The key is using a HEPA vacuum cleaner bag as a filter.

Go straight to the instructions

Watch on Video

Why Make a Homemade HEPA Filter Mask?

Aside from the obvious reason that there are no N95 respirators left, here are some other reasons to make your own face respirator:

  • Get a better fit: Studies regularly show that respirator masks only work well if they have a tight fit. Most masks on the market don’t fit children well or people with beards. If you have an N95 mask and a beard, it’s time to shave!
  • Moral obligation: Using a DIY mask means N95 masks are available to healthcare workers who need them on the frontlines of a pandemic.
  • Provide for family and friends: In the Primal Survivor FB group for women, a lot of ladies talked about how they have “prepper’s guilt”; They had stockpiled supplies like N95 respirators for their family ahead of time, and now friends were asking for “donations.” Instead of giving them respirators from your supply, you could make a mask for them.

Do Homemade Face Masks Actually Protect Against Viruses?

All sorts of instructions for DIY virus face masks have come up lately. One of the most humorous ones I saw used a bra to make a mask.   Others utilize designs where you can put a tissue between two layers of fabric.

But do these DIY masks work?

Studies show that DIY masks do provide protection, but the defense is minimal. N95 respirators give the most protection, followed by surgical masks. DIY masks offer less protection than surgical masks. (Source)

Mask Material Matters!

In studies that tested DIY face masks, materials like tea cloths or dish towels were used. Not surprisingly, tea cloths allow many airborne contaminants (including viruses) to pass through.

By contrast, some materials work much better for DIY respirators. A 2006 guidebook by the Institute of Medicine and Committee on the Development of Reusable Facemasks for Use During an Influenza Pandemic addressed this. While they are hesitant to recommend homemade masks because they might offer the wearer a false sense of security, they do say that:

The tighter the structure of the fabric, the better the potential for filtration… The level of protection offered also may be contingent on the tightness of the fit of the device to the wearer’s face.

For example, tests have found that tight-fitting six-layer gauze masks reduce contamination with tuberculosis bacilli by 90% to 95%. This is much more protection than wearing a mask made from a few layers of loose-fitting gauze.

Surgical masks provide the wearer with very little protection against viruses because they are so loose-fitting.

The Takeaway?

Wearing any mask is better protection than no mask, but you’ll get better protection if you make a mask from the right material and size it for a tight fit.

Which Material is Best for Homemade Respirators?

N95 respirator masks are designed with a non-woven material that can filter 95% of airborne contaminants of 0.3 microns or larger. The coronavirus is approximately 0.120 microns (or 120nm) in diameter (Source).

So, it would seem that the coronavirus could get through the mask.

However, the material in N95 respirators does NOT work like “sieve” filters. Instead of catching large particles and allowing smaller ones to go through, N95 respirators work by tangling pathogens in their fibers.

As the IOM and Committee guidebook said,

“Respirator and medical mask filters are typically composed of mats of nonwoven fibrous materials, such as wool felt, fiberglass paper, or polypropylene. The material creates a tortuous path, and various mechanisms result in the adhesion of particles to the fibers without necessarily blocking the open spaces, still allowing air to flow easily across the filter.”

HEPA Material as an Alternative to N95 Masks

The material used to make HEPA vacuum bags has many characteristics similar to N95 masks.

HEPA bags:

  • Remove 99.7% of airborne particles down to 0.3 microns that pass through them
  • Are made of a mat of randomly-arranged melt-blown fibers
  • Trap contaminants through diffusion, interception, and impaction

There isn’t any data on how well a HEPA vacuum bag works to prevent viral infection, but HEPA bags seem to be the best material choice if you make a homemade face mask.

How to Make a Respirator from a HEPA Vacuum Bag

While I’m not a sewing expert, I was able to make lots of DIY N95 masks out of HEPA vacuum bags. Depending on the size of the bags and your face, you can get 2-3 masks per vacuum bag.


Don’t wear a HEPA vacuum bag directly against your skin.

HEPA material may be made out of fiberglass threads.   The fibers are large, so they aren’t dangerous like fiberglass dust. However, you could still breathe them in, which could cause airway irritation (Source). Kind of ironic if your face mask made you start coughing during the midst of coronavirus.

Even though many vacuum bag manufacturers specifically say their bags aren’t made out of fiberglass, whatever they are made out of might be just as bad. Better play it safe than sorry and not put the bag against your face.

Instead, you must use the HEPA vacuum bag as a filter inside a cloth mask.


  • Fabric for the front of your mask, approximately 12×7 inches
  • Liner fabric for the back of the mask, also 12×7 inches
  • Elastic to secure the mask in place
  • HEPA vacuum bag – They are readily available on Amazon
  • A flat piece of flexible metal for the nose piece (optional but recommended)


1. Cut Out Fabric

DIY respirator mask pattern
  • Iron your fabric first.
  • Print and cut out the pattern. Get the pattern here (free PDF download). Make sure you print it to scale.
  • Fold your front fabric in half. The back of the material should be facing outwards
  • Pin the mask pattern to the back of your fabric or trace it using pencil.
  • Cut out the fabric, making sure to LEAVE A ¼ INCH SEAM ALLOWANCE around the edges.
  • Repeat for the liner fabric

2. Cut HEPA bag

HEPA vacuum bag
  • Remove the cardboard portion from the bag
  • Trace or pin the HEPA pattern onto the bag
  • Cut out the bag. *You only need to leave a seam allowance for the center line (the curved line which will go vertical down the face)

3. Sew the Center Line

sewing DIY face mask viruses

Yes, I chose ridiculous fabric!

  • Line up your first two fabric pieces with the backside facing outwards
  • Pin the center line
  • Sew the center line with a ¼ inch seam allowance
  • Repeat for the liner fabric pieces.

4. Sew Front Fabric and Liner Fabric Together

  • Open the fabric pieces you just sewed
  • Line up the fabric pieces so the backside is facing out and pin together
  • Sew the sides and top of the mask together using a ¼ inch seam allowance. Do NOT sew the bottom side of the mask! You will need it to be open to insert the filter.
  • When you are done, flip the mask so the fabric is right-side out

5. Sew and Insert HEPA Material

HEPA bag as a face mask filter
  • Sew the center line of the pieces of HEPA filter you cut out, leaving a ¼ inch seam allowance. It’s probably best to do this by hand as it can snag on a sewing machine.
  • Insert the HEPA material between the inside and outside layers of the mask

6. Sew Bottom Edge of Mask

  • Turn ¼ inch of the bottom fabric under and pin it in place.
  • The two bottom edges together. I did this by hand using an overcast stitch

*If you want to make a “pocket mask” so you can remove the filter, you can instead close the bottom edge of the mask with tape. I haven’t tried this, though, so I am not sure whether the bulkiness of the tape would affect how snugly the mask fits around the face. Please let us know if anyone has advice on how to do a pocket mask!

7. Attach Elastic

elastic strap on face mask
finished DIY face mask

*Most DIY face masks have elastic ear bands. I find earbands very uncomfortable. They also make it impossible to get a snug fit on the mask. This method of attaching elastic works much better.

  • Fold over the side edges of the mask and sew them in place to make channels.
  • The fold should be at least as wide as your elastic.
  • Thread one long piece of elastic UP through the channel you just made. Then thread it DOWN through the channel on the opposite side.
  • Tie the elastic. You now have top and bottom straps.

8. Attach Metal Nose Piece

If you have a flexible piece of metal, you can sew or glue it to the top of the respirator. This will provide a better fit so air doesn’t leak into the mask.

What to use as a nose piece: 

  • Pipe cleaners
  • Wire twisted in a loop and wrapped in duct tape (so it doesn’t scratch you/poke your eye out)
  • Stripped-down copper wire
  • Grocery store twist ties
  • The metal closures on coffee bags
  • Metal strip on manila envelopes
  • Paper clip, with ends sanded down
  • Metal pie tin, folded, so no sharp edges are exposed
  • Piece of a soda can, with edges sanded or hammered down, so they aren’t sharp
  • The underwire of a bra

Watch on Video

Reusing Homemade Respirators during a Viral Pandemic

N95 respirators are supposed to be disposable. However, they may have to be reused when in short supply. If you need to reuse an N95 respirator (or your DIY respirator), follow these guidelines:

  • Wash your hands before and after putting on the respirator or adjusting it. Or use hand sanitizer if you can’t wash your hands.
  • Avoid touching inside the respirator.
  • Don’t try to disinfect respirators. Disinfectants like alcohol and bleach can damage the respirator’s structural integrity. This also applies to HEPA vacuum bags.
  • When not using the respirator, store in a breathable bag. Paper bags work for this.
  • Have enough respirators for at least 4 days. The coronavirus can live on surfaces for 3 days. If you make enough respirators for 4 days, then you can cycle through respirators. For example, if you go out 2x per day, you’ll want to have 6 masks, so you have enough for each outing over 4 days.

Cleaning a Homemade Respirator Mask

Can you wash this mask? The short answer is I don’t know. HEPA vacuum bags are designed to be disposable and there haven’t been any tests about what happens to the filter medium when washed.

However, there were studies that tested methods of cleaning N95 respirators. It found that: An autoclave, 160°C dry heat, 70% isopropyl alcohol, bleach, and soap and water (20-min soak) caused significant degradation to filtration efficiency.

Because of this, I do NOT recommend cleaning/washing the HEPA filter medium.  Instead, cycle through the masks, as talked about in the section above.

If you are worried about keeping the exterior fabric clean, you could wear a shield or bandana over the mask. Or, if you are crafty, turn this design into a “pocket mask” so the filter can be removed and the fabric portion cleaned. Remember the filter will still have to be set aside for at least 3 days, so any viruses on it have time to die off.


I’m not a doctor or an epidemiologist.  I can’t guarantee that this DIY respirator will protect you from any virus.  However, the research has shown that any mask is better than no mask.  Based on what I know about HEPA materials, it seems to be the best filter for a DIY mask- certainly better than the tissues being used in many DIY masks!

Have you made your own N95 mask? Tell us about it in the comments.

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    • Yes, that should work — though breathability might be really bad. And I’ve got to again add that none of this is tested or guaranteed to keep you from getting sick; it’s an option when you don’t have something like an N95 mask to use.

  1. Posted in: eVacuumStore Blog
    There has been a lot of discussion these days if HEPA vacuum bags contain fiberglass. The answer is HEPA vacuum bags do not contain fiberglass. HEPA vacuum cleaner bags are made from a meltblown material, which is also know as melt-blown or melblown material.
    Confirmed Vacuum Bag Brands That Do Not Contain Fiberglass
    eVacuumStore branded bags
    Envirocare branded bags
    DVC branded bags – DVC manufactures a large number of OEM Bags
    Cirrus branded vacuum bags
    Perfect branded vacuum bags
    Clean Obsessed branded vacuum bags
    Sebo branded vacuum bags
    If you do not see a specific brand on this list we recommend reaching out to that manufacturer.

    • Even if they aren’t made of fiberglass, I still wouldn’t recommend putting them right against your face where you can breathe in the little threads. When making these, I held a cut-open bag against my face for sizing and it almost immediately made my face itchy. Better to be safe than sorry!

  2. My wife sewed some cotton masks with an insert pocket for us and our older kids. She used doubled pipe cleaner which worked well. I used as the insert material from vacuum cleaner bags not HEPA but supposedly 99% rather than N95. This material is hard to breath thru and I sometimes use doubled white paper towels, more breathable but of questionable % effectiveness. I am going to try blue shop towels which are claimed to be effective.

    • I should add that I sterilize the mask with UV-C light in a bag with a built in ultra violet light source from AMAZON.

    • Yes, breathability is a huge issue with any DIY mask. I would recommend using the more-effective but less-breathable masks for high-risk situations (like going to the grocery store) and using breathable masks when you need to wear them longer or are outdoors.

  3. I picked up a bag of Microfiber Cloths for cleaning (14in x 14x) and made masks by folding the cloths into 3 pieces, blanket stitching the sides and the center of the bottom. Then I cut two pieces of elastic. One piece connects the top corners of the mask and the other connects the bottom corners, Question – is the Microfiber safe to wear?
    The cloth feels soft on the face. Colors are light blue and green. I like the swim goggles for the eyes. Thanks for your work and investigations. Drug stores, etc are out of masks.

    • I’m not an epidemiologist so can’t tell you how effective microfiber is against viruses. It’s definitely more breathable than vacuum cleaner bags, so that’s a plus if you need to wear a mask for long periods of time. As for safety, I don’t know of any reason why you couldn’t put microfiber against your face. The fibers aren’t loose like the stuff inside vacuum bags. Stay safe out there!

  4. I found Envirocare Vav Hepa bags; when cut they are plastic on outside, I assume you only use the tissue-like fabric inside that must be the Hepa filter, am I correct? Thanks, going to make these now, they are the best ones online and you have done the best, clearest, explanation!

    • Use the plastic backing too. Otherwise the tissue-like fabric might fall apart on you. And I’m glad you found the article useful. Stay safe!

  5. When using vacuum bags for the filter, are you leaving the fabric on from the outside of the bag as part of the filter? Or just the very thin actual filter part of the bag? Thank you for this pattern and video.

  6. It is grossly irresponsible to advertise these home made masks as N95’s. Yes, they are helpful, but to rank them as N95’s is both false and misleading.

    • We are only recommending DIY masks for emergency purposes when no other mask is available. However, if one must resort to a DIY mask, then a HEPA filter – or other tested material — is a smarter choice than normal fabric.

  7. There is a pattern similar to the above pattern on Pinterest. I have made over 100 of them and I made a pattern for the insert of the HEPA filter. Once you have made your mask, lay it flat on a piece of paper and trace it. Take 1/2 inch off the bottom of your tracing. This is the pattern for your insert fold it in half and place it inside the mask gently roll it to the nose. It isn’t too hard. Just an FYI hospitals are allowing home made masks because I have been sending mine all over the country and have made them for my unit. I also didn’t see anything about fiberglass in my HEPA vacuum bags. I am also using quilters cotton or Batik contrary to belief Batik is one of the best fabrics to be used.

    To the comment about the eyes you can still purchase goggles. Even if they are swimming googles.

  8. Hi, can you be more specific about the Hepa filter. There is a cloth Hepa filter vacuum bag. Does this have a decrease number of the fibreglass threads.

  9. Maybe someone said this, but how about leaving the center vertical seam of the lining partially unsewn/open so you could insert a filter between the layers that way?

    • That would probably work, so long as it was the outside seam of the mask. I wouldn’t want the opening near my face to make extra sure those fiberglass threads don’t get breathed in.

  10. I had reservations about the fiberglass in the hepa vacuum filters but believe this is the best alternative if you have to go out of the house. I don’t need to wear them all day, just to run to the market or pharmacy.

    I will be making my masks tomorrow with the pockets so I can remove the hepa filter and launder the masks. Thanks for all the great ideas and suggestions. Be safe everyone. From Puerto Vallarta

    • I’d love to see photos of this when you are done. I’m not the craftiest person and want to get a pocket mask pattern up on this post. You could send them to diane (at) primalsurvivor.net

  11. I haven’t read all of the comments so hope this isn’t repetitive. Some closure suggestions for making a pocket mask:
    Strips of velcro cut to fit.
    Small sew-on snaps.
    Hooks & eyes.
    Stay safe everyone!

  12. Face masks are probably more effective against contaminating other people by trapping droplets when you cough or sneeze. Since you can carry the virus unknowingly before you are symptomatic, this is no small thing.

    However, in terms of your own protection, a mask is only part of the story. Viral droplets can contaminate you through your eyes, so unless you are wearing tight-fitting goggles as well as a face mask, you are still vulnerable to infection.

  13. I recently saw a video from a doctor urging people NOT to use hepa filters in face masks due to the dangers of inhaling the fibers. He also said that you’d need several layers of the filters to do any good. Then other videos say that they work with only one layer. What is true? Will putting it inside a cotton fabric protect you from breathing the fiberglass?

    • The fiberglass threads inside the HEPA bags are very visible. Once I put mine in the fabric mask, I didn’t see any fiberglass threads sticking out. I can’t guarantee it, but it doesn’t seem like any threads are getting through (otherwise I wouldn’t be wearing them or giving them to people). As for the level of protection, we don’t know. HEPA bags weren’t designed to go over people’s faces. Studies do show they are effective at trapping small particles, down to viral size, so it *should* be effective. Again, I reiterate that we don’t know for sure. What does seem to be obvious though is that HEPA material will do a much better job than wearing just a cloth mask.

      I know the uncertainty is anxiety-inducing. It’s terrible that so many people have to resort to DIY masks instead of having ample N95 or higher-rated masks to wear. But, unfortunately, that’s the situation we are in.

      • Did some further research on the type of bag I bought-EnviroCare Technologies Micro Filtration Vacuum Bags, and per the company, they do not use fiberglass in any of their bags. So, I assume that if the fiberglass is the only concern, that these are better than just the cloth in the home made masks!

  14. One concern I have in the U.S. – when I looked at some HEPA vacuum cleaner bags online for purchasing, a California warning came up that the HEPA bags had a product in them that is known to cause cancer in humans.

    This is an additional concern to consider beyond fiber glass. I can’t determine what that product is, or if it is in all HEPA bags. Just a consideration, if you are going to inhale through the HEPA bag.

  15. Hi,
    Thank you for the information. I have sent your site to several friends with questions.
    I want to mention that I read recently that scientific testing suggests that two (2) layers of the tea towel (flour sack towel) moves to the same level as a surgical mask. Take that for what it’s worth. Many people don’t know that the type and quality of the fabric used is important. And, I was thinking “pocket”, just as I read your wrap-up on the masks. Thanks, again.

    • Yep – several other options out there – its up to each individual to choose what is best for their own circumstances.

  16. Just put a little cloth over the fiberglass. It all balances out in the end. Yeah, okay…If I jump off a building I won’t die of coronavirus either.

    • The way my bags are, there is paper sandwiching the fiberglass fibers on both sides. So, both sides are actually smooth. I’m not familiar with the construction of other HEPA bags, but I believe they are all similar to this.

  17. Thanks so much for posting this. I hadn’t realized that the HEPA vacuum bags have fiberglass. I was getting ready to sit down at my sewing machine to make some using just that. Now I will be using your directions.
    Is there an option to print your directions? I can’t seem to find it.

    • Diane, I used the air purifier hepa filters and they do a great job. I use a tee shirt for the inside so it’s comfortable against the face and sturdy woven material for the outside. Thanks again!

  18. Hi Diane. Thanks for sharing. Have you heard of anyone using HEPA air filters by Filtrete? It doesn’t have any fiberglass and claims to filter to .03 microns like the vacuum bags.

    • I’m not familiar with them. It is True HEPA though, so should work like other HEPA bags (not guaranteeing anything – don’t want to find myself in legal trouble! DIY masks are a last resort!). Note that whatever they use instead of fiberglass could be just as bad, so you still probably don’t want to put the material right against your face.

    • My wife went with 3m Hepa furnace filters and removed the outside box and wire on top. This leaves a very large piece of pleated material. From research online the furnace filters don’t have fiberglass in them they use a plastic instead. She used pipe cleaners bent in 3 for shape over the nose.

      I’m wearing one of her masks as I type this and I can breathe through it but feel humidity inside the mask. I prefer it to no mask which is what we would have other wise since no online orders have made it to us yet.

    • Is it safe to cut up a HEPA filter vaccuum bag if it contains fiberglass?

      Do you recommend any protective gear to avoid contact or inhaling particles?

      • The fibers inside the bag are quite large, so it shouldn’t be a risk like with fiberglass dust and thus you don’t need protective gear (for legal reasons, I’m definitely not guaranteeing this!). I didn’t notice any of the fibers floating around in the air while cutting the bags open, that’s how heavy the strands are. However, if you were to put the cut-up bag right against your face, you could end up with some fibers in your stomach or airways, so better play it safe than sorry.

  19. You cited work from 1949
    Seventy years

    Here is work about material efficiency for masks for _ill_ persons

    Objective: This study examined homemade masks as an alternative to commercial face masks.
    Methods: Several household materials were evaluated for the capacity to block bacterial and viral aerosols.
    Twenty-one healthy volunteers made their own face masks from cotton t-shirts; the masks were then tested for fit. The number of microorganisms isolated from coughs of healthy volunteers wearing their homemade mask, a surgical mask, or no mask was compared using several air-sampling techniques.

    Results: The median-fit factor of the homemade masks was one-half that of the surgical masks. Both masks significantly reduced the number of microorganisms expelled by volunteers, although the surgical mask was 3 times more effective in blocking transmission than the homemade mask.

    Conclusion: Our findings suggest that a homemade mask should only be considered as a last resort to prevent droplet transmission from infected individuals, but it would be better than no protection.
    (Disaster Med Public Health Preparedness. 2013;0:1–6)

    >surgical mask was 3 times more effective in blocking transmission than the homemade mask

    >homemade mask should only be considered as a last resort to prevent droplet transmission from infected individuals, but it would be better than no protection

    IMHO, what should be said
    Trust only words from healthcare professionals and researchers

    My thoughts as non-pro
    – any mask will not help if you do not use it correct way
    – _any_ nose and mouth cover is better than none
    – Vacuum cleaner bag is almost as good as surgical mask
    – scarf and two layers of cotton will filter 50-80% –
    – give N95/surgical mask to your nearest emergency professionals – if they became ill you will die

    And sew some masks
    Even if it will not help against virus it will calm you

    • The link you are referring to is this one: https://www.nap.edu/catalog/11637/reusability-of-facemasks-during-an-influenza-pandemic-facing-the-flu The committee looks at numerous studies (yes, including some dating back to 1949). Their conclusion is that fit and material matter for DIY face masks.

      Unfortunately, there aren’t that many studies which actually look at how effective homemade face masks are. And there would need to be a LOT of studies to address all the different styles of masks, materials, construction methods, etc. Yeah, we are all kind of shooting in the dark here and hoping for the best.

      Agree- wearing any mask is better than nothing. But, if you are going to wear a DIY mask, it might as well be one which can provide the best level of protection and not just help calm you.

  20. You talk about a filter that acts to entangle, using a non woven material. Would a fabric such as a thick, needle-felted or wet-felted wool mat type fabric work in the same way do you think? I realise it would just be an opinion and not a tested solution but interested in your opinion as someone who has thought this through. Thank you.

    • My non-expert opinion also thinks that a non-woven material such as felt would probably provide better protection than a woven material like a cotton t-shirt. But felt/wool/etc. haven’t been tested against viruses. The thickness and tightness of the material would also matter (I used to do some DIY felting and know that some of my felts came out patchy with big holes in some areas!). There’s simply too many variables, which is why I went with HEPA vacuum bags; they’ve actually been tested whereas other materials haven’t.

  21. Thank you SO VERY much for posting this! I’ve made a few for family members in my household that work for life sustaining businesses. Some easy tips on making a pocket mask: velcro, which can be sewn on, or heat bonded; or attach snaps that can be attached using a hammer. Also, since my area has been depleted of elastic, I’ve attached ribbon that slides over the head, & ties at the top. I’ve also found that using 20 gauge craft wire for the nose piece works great. I cut a piece long enough to mold around the top, & sides of the mask, & loop each end of the wire to prevent the wire from poking through the fabric. I insert the wire inside of the mask before sewing the bottom, & the side pieces where the ribbon is attached. I then sew the sides securing the wire at the sides, & finish by sewing about a half in long stitch across the top bridge of the mask…this prevents the wire from moving around or slipping. I am now working on making the masks to donate to healthcare workers, first responders, etc.. Without your most valuable information, it would not be possible for me to serve my communities needs. Thank you!!!

    • Thank you for the great tips! You sound a lot craftier than I am! Half of mine are lopsided but they still fit well. But it’s about function, not fashion. 😀

  22. If you decide to make a pocket mask. Label/Mark your hepa filters with a number so you know that it has been out of use for the proper 3 day time limit. #1 used on day one, #2 on day 2 etc. Then when the last of your filters is used you know to start back over with #1. Same with your masks with a sewn in filter. You can mark them with a sharpie marker .

    • That’s a great idea! I’ve been labeling the paper bags I put my masks in, but labeling the filters would make it even easier to stay organized. Thanks for the tip.

  23. PLEASE! Stop suggesting HEPA material for face masks! It is misleadingly DANGEROUS! It may filter out the virus, but it won’t matter because the user will be DEAD from suffocation! You CANNOT BREATHE through HEPA. And yes, I do know that of which I am speaking!

    • The breathability isn’t great (it’s not great with a non-vented N95 masks either though). But I’m definitely not dead from suffocation yet.

    • I don’t know for sure. However, there is a study (linked to in the article) which found that microwaving damaged N95 respirators and made them less effective. So, I wouldn’t risk it.

    • Yes, I’m cutting through both layers of the bag at the same time so I get two equal pieces: one for the left side and the other for the right side.

  24. I read that you should not use pins in the fabric as this causes big holes which is what you don’t want in a face mask. Your thoughts?

    • With this design, the pins are going around the fabric edges. The fabric portion isn’t stopping pathogens from going through; it’s the HEPA filter inside. The HEPA material goes close to the edges and is still pressed tightly against the face, so *should* provide protection

      The HEPA material does get sewn down the center line and is pinned, but it is fluffy so it kind of overlaps on itself and thus the pinholes don’t seem to be a problem. Remember HEPA filters work because they don’t give pathogens a straight path through the material; the pathogens get tangled in the fibers).

      *Again, I’m not guaranteeing that this will work. However, I do believe that using a HEPA filter inside a cloth masks is a heck of a lot better than using just a cloth mask or surgical mask.

  25. Questions:

    1) Do I use both layers of the HEPA filter bag, or is just one layer enough?

    2) What do you think about putting the HEPA filter between a couple of stretchy “balaclava” type masks as another alternative?


    • 1) Just one layer of HEPA material is enough. If you used two, it would probably be difficult to breathe. I trace the pattern on the vacuum bag while it is still closed and then cut. This gives me two equal-sized pieces: one for the left and one for the right side.
      2) I’m sure it *could* work. The issue is how you would make sure the HEPA material is actually covering your nose and mouth. I guess you could use a very large piece of HEPA material sandwiched between two pieces of fabrics (like balaclavas) and then tie it all the way around your face.

      • Diane I used the HEPA bags as well. I traced the pattern onto the bag and cut it out I got two pieces of the filter where I was able to sew to each side of the mask so I sewed the filter into the mask then I cut a piece of filter and sandwiched it in between two pieces of fabric and place that inside of my pocket which works very well secures tightly to my face and I can breathe.

    • If it is certified HEPA, then it should work. I’m not familiar with furnace filters though. Apparently some people are using automotive filters (which I”m also not familiar with but would be worth looking into).

      • 3M’s “Filtrete” web site has a Coronavirus page which begins by reiterating what is generally known about the virus itself and about self- protection, then discusses their Filtrete products, and finally ends up a Q&A section with the following:

        “Q: Can we use the Filtrete™ Air Filter material/media to create handmade masks?

        A: Our filters are designed to be used in HVAC systems, and the filter media has not been tested to be used as a face mask for respiratory protection. Altering any of our 3M Filtrete™ Air Filters is not recommended or supported by 3M or the Filtrete™ Brand. Customer safety is our number one priority.”

        • Yes, HEPA material should only be used as a last resort! It hasn’t been tested as a face mask. This recommendation is based on what we concluded is the best **last resort** solution when you can’t get an N95 (or similarly tested/rated) mask.

  26. I am preparing to make a face mask according to your directions. It will be a pocket mask using the vacuum bag Hepa Filter paper. I have a sterilizer box that I use to clean my CPAP machine. The device operates using UV light and ozone. It claims to be 99.99% effective against bacteria and viruses. I can sterilize two mask at a time in this box over a 15 to 20 minute time frame. I plan to wash them in a soap and chlorox solution as needed. I will remove the Hepa Filter before washing.

    • I thought about that too but I’m worried that the Velcro will be too thick; it would make the mask bulky at the bottom so it wouldn’t fit well on the bottom of the face. Also, I only have really thick Velcro at my home now and am not going out to buy any! 🙂 If you try it and it works, please let us know!

      • Hi. I just made a few of these masks (pocket versions).
        I used “Singer” sewing brand, “Adhesive Back (No-Sew) Hook & Loop Tape” (aka Velcro), to close up the pocket opening at the bottom of the masks.
        I DID cut each strip (hook & loop strips), in 1/2, Lengthwise, so it wouldn’t be too bulky. It works FANTASTIC!
        This stuff is extremely STICKY and I had no problems with it pulling away from the fabric so no need to sew it onto the masks.
        TIP: For comfort, I put the Hook-side Facing OUT and Loop-side Facing IN, on the Inside of the 1/4-in, Mask & Liner Hems.
        This did not interfere with the piece of HEPA Filter once placed inside and sealed closed.
        I also ran the handle of my scissors over each side of the velcro-like tape to ensure adhesion to fabric.
        I hope this is helpful, in addition to these Great Instructions and other Tips?
        Please stay safe and healthy.

    • I was considering sewing small snaps into the bottom to keep it closed. They aren’t bulky and should not interfere with the mask’s fit.

      • That’s a smart idea. I wish I’d stockpiled my sewing kit better before all this broke out. Apparently a lot of places are running out of elastic because of how many people are making their own masks. It just goes to show it’s impossible to imagine and prep for every possible scenario! 😀

  27. since the filter material is pocketed between non-filtering layers, won’t the viri simply bypass around the edges? the cloth layers are like an open superhighway to a virus, and because they offer lower air resistance, inhaling should force them to take that path.

    • The interior filter layer is large enough that it surrounds the entire mouth and nose area and is held tightly against the face. Again, I’m not guaranteeing that no viruses won’t make it through but the ones I made have a good fit and cover the face well.

  28. Could you please tell me the name of the vacuum bags you used? I went in amazon and there are many different ones and I’m not sure which is best. Thank you.

    • So long as they are HEPA bags (not “HEPA like” or some other knockoff), it will be fine. I am in Europe so the bags I used were probably different than what you can get in the states. Mine were by Hoover though.

    • If you want to be very precise, you can take a measuring tape and hold it at the top of your nose and run it down to right below your chin. Make sure you leave it a bit loose since you won’t want a mask pressing flat against your face. This is the length of the center line of your mask.

      You can also check the sizing after sewing the center line by holding it up against your face. If it is too big/small, you can adjust it then before sewing the rest of the mask.

  29. So would any type of non woven material work if vacuum bags not available. I have an embroidery sewing business and use non woven stabilizer for backing knits when adding logos. Would this type of non-woven fabric work in a pinch?

    • I choose HEPA vacuum bags because they have actually been tested to filter down to 0.3 microns. In theory, any non-woven material would be better than woven materials (it’s going to depend on how tightly woven the material is, the size of the non-woven fibers, etc. though).

      Note “better” does NOT mean safe. At this point, even the CDC is telling people they can use a bandana instead of a respirator as a last resort when masks aren’t available. But, I repeat: Better than nothing does not mean safe! It’s sad that we’ve gotten to this point.

    • I couldn’t find any reliable info on whether washing damages HEPA material. Based on studies about N95 respirators, it seems that washing by hand with plain water would clean the mask. Again, this hasn’t been tested so I’d play it safe and not wash them. As for disinfecting, you can leave the masks in a breathable bag (like a paper bag) for several days so any viruses have time to die before you put the mask back on.

    • You’ll need about 20-25inches of elastic per mask depending on how big your head is. I threaded a long piece of elastic through the mask, put it on, pulled the elastic tight so it got a snug fit, tied the elastic, and then cut off the excess. *Tip: Use a longer piece of elastic than you think you’ll need and tie it loosely so you can retie it later if it isn’t tight enough.

  30. ” were converted to be non-infectious after 90-, 60- and 30-min exposure at 56 degrees C, at 67 degrees C and at 75 degrees C, respectively.”Stability of SARS coronavirus in human specimens and environment and its sensitivity to heating and UV irradiation.

  31. Good and clear instructions.
    In my DIYing, I’ve used automotive engine air filters as an insert or as part of the mask itself, using tape (duct, BION) for construction.
    Also, for an airtight fit, seal the edge of the mask with “boob tape”, or surgical silk tape, to the face. Sounds like overkill, maybe, but I’m also considering the sick person, who should wear a mask unless it restricts his breathing, and the caretaker who should wear a mask, as well as gloves, etc. Maybe one doesn’t need a sealed mask to visit the grocery store.
    Email directly for details.

  32. Can this be washed in a washer or hand washed? If you’re wearing it all day at work (hospital), then it will get really gross. Just leaving it alone for a few days isn’t going to fix the gross factor, even if the virus is gone by that point. Can HEPA filters get wet and still work?

    • No, you *probably* can’t wash the HEPA material. It could damage it’s ability to capture viruses.

      *There is this study https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2781738/ which found that alcohol, bleach, and even soap + water degraded respirators. Would plain water be okay? I don’t know.

      If I was craftier, I would have figured out a way to make a “pocket mask” – one where you can remove the HEPA material and wash the fabric mask. I guess it could be done by closing the bottom with fabric tape instead of sewing it shut. However, I’m a bit worried that the fabric tape would be bulky and thus the mask wouldn’t fit snug against the face. If anyone figures out how to make a pocket mask with HEPA bags, please let us know!

      Another solution to keep the fabric portion of the mask clean:
      Wear a surgical mask, shield, or bandana on top of the mask. This will prevent the exterior from getting gross.

    • Please see my comment. You can make a filter that you can take out an throw away. I wash mine in a soapy water with bleach added. (Wear Gloves) then I hang it to dry. I work in a hospital I won’t use the filter twice.

      • Vacuum Bags Contain Fiberglass?

        Right now, it’s important for us to be protecting ourselves and our families due to the COVID-19 viral outbreak. With the decreased supply and increased demand for N95 rated masks, this has left the public resorting to alternatice methods of protection. Specifically, people are resorting to using vacuum cleaner bags. Our most common question in the past week is if cloth vacuum bags contain fiberglass. This is due to a viral video from a doctor in Europe stating that vacuum cleaner bags contain fiberglass.

        Short answer: Vacuum bags do not contain fiberglass.

        Vacuum bags have not ever, and do not contain fiberglass. Cloth HEPA bags are created to offer the highest level of protection and filtration available and are made from a polypropylene material. This material has excellent filtration abilities. As stated several comments above there is a study. However they used only one type of bag. The CDC is doing a study and looking at them as an alternative.

    • The pattern doesn’t include the 1/4 inch seam allowance, so you should add 1/4″ all around. I actually used a larger seam allowance since I was sewing by hand and suck at keeping my stitches straight!

  33. My husband and I use to milk cows. The strainer material might be used as a filter. The box says the filtration range is 35-50 microns. Would using that help? Obviously it would not shred if it was washed (at least for a few times)

    • 35 microns is actually quite large. To put it in perspective, water droplets (like from a sneeze) are around 5 microns. Coronavirus is 0.12 microns. It doesn’t sound like it would be a good filter material. Obviously better than nothing, but the CDC warns against face masks like these because they might provide wearers with a false sense of security.

  34. Could i just sew around an existing new medical mask so i alrdy have the elastic bands and shape of the mask and what not?

    • By ‘medical mask,” do you mean a surgical mask? Surgical masks are made to fit very loosely, so don’t provide the wearer with protection against viruses (they do help protect the people around you if you happen to be sick and don’t know it though!).

  35. Hello primal survivor! I found a video online titled ‘A Doctor explains how to make the safest face mask’ – A lot of people knocked on the video mentioning the fiberglass as mentioned in your article. Can you please have a look at the video and let me know if the way they are stitching it together would a safe alternative. I’m looking to make these for me and my coworkers (respiratory therapist, nurses). Any advice would help. I just don’t want to make something that would be considered “directly putting a vacuum bag to your face.” Though I do see their vacuum masks have some sort of thin sheet to them. Please, any advice helps.

    • Hi Julio, thank you for the work you are doing in these grim times. We cannot comment on any other design for obvious reasons. However you definitely do not want the vacuum bag touching your face for the reasons you stated and it is also discussed in this article.

      Also just to reiterate – “these instructions are for DIY masks to be used as a last resort when all other options are exhausted. We have no scientific data to validate their effectiveness.”

  36. Could these be pasteurized to sterilize them? Maybe put them in the oven at 175 degrees F for 15 minutes to be sure? I dont think that temperature would harm the elastic.

    • Please note these instructions are for DIY masks to be used as a last resort when all other options are exhausted. We have no scientific data to validate their effectiveness. Similarly we cannot be sure that the above would sterilize the masks or be in any way effective.

    • Here are some ideas: The metal clasps on manilla envelopes, bobby pins, pipe cleaners (might have to twist a bunch of them together to make it strong enough), wire wrapped in duct tape so it doesn’t poke you in the face, the metal closures on coffee bags, the underwire from a bra… Or you could just use medical tape to tape the mask to your face.

      • Yes — great idea. I’d wrap the ends in duct tape or put a drop of hot glue on the ends so you don’t end up scratching your face with it or poking your eye.

    • I have also seen people use aluminum from the baking pans…like the ones that people use for Thanksgiving, cut a piece…lik 2X1 in. and then fold it over itself around the edges to prevent sharp edges. Many machines will sew thru this and you can sew it into the top seam of your masks. However, I have heard that if you reuse masks, after several washings and wearings that it will break. SO…depends on how long you want the mask to last. If it is single use or just a few time, it should be ok, otherwise, many are using paperclips, unfolding them and bending the ends so that there are no sharp edges. (Some even put a drop of hot glue on the bended ends to make sure nothing breaks thru the masks.

    • I purchased garbage bag twist ties on Amazon. They are 7 inches long. I cut them in half. You can get 100 ties for around $15 which makes 200 masks. The twist ties has 2 pieces of metal between plastic. Very stiff and easy to use. I zig zag over it.

  37. Does sewing (especially down the front in front of your nose and mouth) introduce holes from the needle that the virus can get right through? Could use fusible tape instead?

    • If were were just talking about the fabric mask, then yes. But it doesn’t seem to introduce holes with the HEPA material. Here’s why: The material is kind of fluffy. With at least a 1/4 inch seam allowance, the material folds over on itself and closes any holes. HEPA tangles pathogens rather than acting like a sieve, so it should be okay. I’m not saying 100% that there aren’t holes where viruses can enter though. This is simply the best DIY option available.

    • Hi there,
      I used some tape that activates when you apply heat from an iron. My filters are only about 2 inches square, I’m lucky enough to have a few 3D printers and have printed my own set of masks.

    • The hepa filters should be changed out after daily use,to make a pocket you would turn the ends of the liner in 1/2″ hem .so you would be leaving the ends of the liner opened.then you would hem the ends 1/4 ” seam allowance attaching the top and bottom of the liner fabric,also you can lay your wire on top as usual, zigzag it in the top.I have begun using ties instead of elastic they fit tighter and will fit most.for the ties use a clean sanitized tshirt and cut strips about 3/4″ by the length you need,it stretches so you can do that first before hand,you can put it thru the same way as you would elastic.I like putting a longer piece thru the top then thru your ends ,then you have only 2 ends to tie,instead if 4.using the hepa bag filters this way also prevents chances of holes.

    • I put a small slit in the top hem so I could put a nose piece (pipe cleaner ) ECT. Whichever you use in and out of the mask. Open ends closable with Velcro strips make it easy to change out filters while you wash fabric part of mask…

    • Please read the last section in the article. It talks about reusing N95 masks. The same applies to HEPA masks. I would recommend putting a mask in “quarantine” for at least 3 days before you wear it again.

      • Do you have a mask pattern for a four year old that is easy and comfortable for a child. Pleated or the cone style would be great. Thank you in advance,
        Sincerely Sonja Blancke

        • Masks *should* be okay for 4 year olds but please check with your pediatrician first! Masks can really block airflow and make breathing harder, which can be risky for really little children. If your pediatrician says it’s okay, then you can adjust these patterns by scaling them down a bit in size: use a piece of thread to measure from the top of the nose to below the chin (allowing for ample space so it isn’t pressed against the face). This will give you the length of the centerline of the mask. Hope that makes sense!

    • The hepa filters should be changed out after daily use,to make a pocket you would turn the ends of the liner in 1/2″ hem .so you would be leaving the ends of the liner opened.then you would hem the ends 1/4 ” seam allowance attaching the top and bottom of the liner fabric,also you can lay your wire on top as usual, zigzag it in the top.I have begun using ties instead of elastic they fit tighter and will fit most.for the ties use a clean sanitized tshirt and cut strips about 3/4″ by the length you need,it stretches so you can do that first before hand,you can put it thru the same way as you would elastic.I like putting a longer piece thru the top then thru your ends ,then you have only 2 ends to tie,instead if 4.

      • Good suggestions – thank you! Ties do give a tighter fit and are better if you are wearing the mask for a long time. I personally prefer elastic though because it requires less touching to remove (would have to touch the back of my head/hair to remove ties).

    • I have gotten the heppa bags and cut it open. It has 4 layers on each side. The outside layer seems to be the most isable since its brathable and WP. The inside seems to be as thickbas tissue paper but rubbery non breathable.
      I beleive the one outer layer may be good enough for its properties.
      Would u share yourbthiugjtsbon this?
      Thank you!

      • Each brand of vacuum bags is a bit different, so I can’t comment on the ones you got. However, I believe you need all 4 layers or the HEPA material will start to fall apart and won’t filter properly.

    • It’s likely in your muscle memory. Give it a try and see what happens. They’re small and if you mess up the first one it’s not a big deal.

      • You might want to do your research on OSHA before you provide instructions for making N95 masks. In industry they require a medical test to insure the wearer can tolerate the strain masks cause your respiratory system. When you buy them, they come with inserts and warnings. People with heart conditions or at risk for heart attack, asthma, high blood pressure, diabetes, epilepsy, claustrophobia or any breathing issue may be putting themselves at risk by wearing a facemask. Common side effects of facemask use are headaches, dizziness, nausea, fatigue and impaired thought processing. There is a reason there are no childrens face masks on the market. All masks place strain on your respiratory system and reduce your oxygen intake.

        • Very good point. Breathability is one of the reasons surgical masks are recommended over N95 masks even though the N95 masks obviously do a much better job of protecting the wearer. It’s really hard to wear an N9 mask for a long period of time. My heart goes out to all the frontline workers who have these on for hours at a time. *DIY N95 masks should only be a LAST RESORT!

      • Yes, I just updated the post to reflect that. Even if the HEPA bag isn’t made out of fiberglass, I’m not sure whatever it is made out of would be any better to breathe in! When I first started making these, I actually held a cut-up bag against my face and it almost immediately started getting itchy. Better play it safe than sorry and not put these right against your face.


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