Please find a full lit review and references here.

Mask pattern template .PDF here 

Download the 1-pager we include with ALL of our masks (printed) here
By L Wilkins
Tutorial and pattern by Alysia Myette
Research by L Wilkins + Maggie Huang 
Graphics Dushan Milic

Toronto distribution procedure:
You may produce masks and give them to your neighbors, but if you want to produce and distribute them in large numbers, Community Make can help with distributing to places in need. Our masks all use the tutorial and materials below (100% quilting cotton, pipe cleaner nose piece, cotton waffle weave filter). They are all packaged in a cleaned ziplock bag and include a 1-pager on how to wear them, which can be downloaded and printed. To get in involved please fill out our intake form.

We require all mask makers to ensure they are healthy. You must be symptom free, and if put at risk have fully quarantined for 14 days.

Disclaimer and introduction:
The most effective mask against COVID-19 is called an N-95 respirator. DIY masks and PPE (personal protective equipment) are not N95 respirators. While similar, most DIY masks are less effective due to their materials and lack of regulatory approval . It is important to understand proper care and use to prevent further risk of infection.  Please read the entire document before making any PPE.

Keep in mind, if you aren’t aware of your PPE’s effectiveness, a false sense of security can harm people around you. The information is not intended for medical use, however, depending on when and where you are reading this it may be used in that context. Having a DIY solution may be better than nothing, but it is key to know how safe you are.

Typically, surgical masks and N95s are limited for single use. The goal of this project is to share knowledge and tutorials about effective materials, construction, and use of reusable DIY masks for the general public to alleviate demand of PPE for front line health care workers. It is also to empower people with the knowledge to make their own PPE. We have included a tutorial on mask making below.

This information is evolving, and this document continues to be updated as needed. We have done our best to gather up to date information, however the situation is changing rapidly. We will update as need be, but please keep in mind information found here may become out of date.

It is also important to fully understand the properties of your PPE. Not just any materials, not just any patterns, not just any methods will do. If you want to be safe, you need to understand why.

At this time, the public health officials in North America do not recommend everyone wear masks/PPE. They may be recommended while seeking or waiting for care.

We believe that if you are a front-line community worker—grocery clerk, delivery person, courier, utility workers entering homes, (etc.)— who is interacting with the public, a mask may be beneficial. However, in countries like Hong Kong and Taiwan,, the widespread use of masks and PPE has been suggested to prevent asymptomatic transmission . We advocate for everyone to use masks, but to not take limited manufactured masks away from medical use. There is conflicting research on the effectiveness of masks for the general public, due to supply concerns, and the potential for improper wear (which risks infection). Generally, masks are only effective if worn properly. Most people do not wear them properly which can risk them being ineffective or harmful. COVID-19 has been found to be transmitted by non symptomatic people, which properly and widely used masks can prevent. Masks are generally less effective when being used by children because of fit issues. Wearing masks at home is not recommended unless you are, and/or are caring for someone with signs of illness.

There are many considerations. Please do not go out and purchase materials to make any PPE if you are in quarantine. Many of these materials can be found in your home.

Comfort and Tolerability :

If your PPE is uncomfortable, you will adjust it, risking contamination. Make sure your PPE is well fitted, and comfortable before wearing it. Test for breathability, mobility, speech (can people hear you in conversation?), warmth, and humidity, and adjust as necessary. You can test your mask for 20 minutes before heading out. Some masks use filters or filter pockets. This is not for everyone, only use a filter if you can comfortably breathe.

Face shields:

Face shields are much more straightforward than masks. COVID-19 is primarily transmitted through droplets. A shield made of a non porous material will provide a physical barrier, as opposed to a filter, to stop droplet particles which may not be visible. These surfaces can also be wiped fully clean and disinfected without damage to the material. Common shield materials: Acrylic, acetate, vinyl. The face shield should fully cover your face. Wash your hands for 60 seconds before putting on, and after taking off any shield. Do not adjust or move it. Make sure the shield is far enough from your face that it doesn’t hit your glasses or fog up. If the shield rests against your nose, it will fog up, you will be uncomfortable, and risk contamination. Face shields can be effectively cleaned with soap and water.

3D printed masks and hard materials with removable filters:

There is no evidence (that i have found) to suggest thin 3D printed masks are effective filters. Every printer prints at a different density and can have very different properties based on the filament, printer, and even room temperature when producing the print. When we are talking about measuring things 0.1 microns, and creating a solid barrier, I do NOT think 3D printed filters are suitable. If you are making a thick, watertight print with a removable filter this may be viable. Do not use the 3D printed material itself as a filter. 3D printed mounts for face shields are effective, however many FDM (home printers) do not print with sterliziable material. Standard PLA, and ABS are slightly porous. ABS M30i are plastics that can be sterilized manually, and PC-ISO Ultem can go into an autoclave. Before even printing mounts for face shields, ensure your printer is capable of using a material that can be cleaned.

You can make a mask out of a non porous material (Acrylic, acetate, etc) that covers your mouth and nose as directed below. This type of mask needs a filter (to breathe!). Follow the directions to make a domed design that is away from your face. See below for instructions on how to choose filter materials, create good mask fits, and how to properly clean your mask. Non porous masks can be cleaned with soap and water, filters should be changed regularly or cleaned if they are woven. If there are gaps in the filter insert, or if the walls of the 3D print are not quite thick, your mask may be ineffective.

Masks:

Specs: 

• Exterior 2 layers (100% quilting cotton is suggested)
• Mask should be “domed” away from mouth
• Pocket for filter that contains filter (optional)
• Sleeve at top for “nose pinch” device to hold to face properly
• Elastic if for personal use, fabric tie if for autoclave /medical use
• FULLY COVER nose and go under chin
• Filter of disposable HEPA/Merv filter or washable waffle weave (dish towel)
  

We recommend your mask be made of 2 exterior layers of 100% quilting cotton. Although not ideal, you can also use a thick cotton shirt and/or add layers. More layers do not double the effectiveness, but it somewhat increases effectiveness. Masks often have a pocket inside for an additional filter layer, which can dramatically increase effectiveness. You may choose to use a filter pocket to increase effectiveness, which may be beneficial if your mask is made of a lighter material. Please be mindful of your comfort and tolerability (breathing, speech, humidity, etc.).

Instead of a filter, you can also treat the exterior layers using a salt soak method to improve the sterility of the mask. Please consider carefully what method, material, and mask is right for you, what you’re doing, and for how long.

The shape and fit of the mask is very important. The mask should fully cover your nose and go under your chin. Improper fit is often cited as the reason for ineffective mask use. There should be a pinch mechanism at the top of your nose to hold it in place. The masks should be domed outward (either with pleats or other methods) and not rest against your mouth.

How to wear:

It is critical that you take good care of your mask, and follow correct procedures for use and sanitation. If you don’t, your mask can result in additional risks to you and those around you.

Wearing the mask: 

• Make sure to properly wash your hands for 60 seconds before putting on your mask.
• Wash your hands properly before touching any PPE.
• Make sure your mask fits you: it should cover your nose and mouth, and be domed outward.
• Make sure the mask is firmly pinched around the top of your nose. This can also prevent fogging up of glasses by adjusting the nose piece properly.
• Do not touch your face or adjust your mask after putting it on.
• It is critical to wash hands before and after adjusting your mask to limit potential exposure.

After use: Wash your hands before removing your mask. If you have a disposable filter inside your mask, discard it after every use. If your filter is washable, you can clean it. Store clean and used masks in different places and in an airtight tupperware.

Cleaning and disinfecting:

If you have a felt or non woven mask cover or filter, do not scrub your mask with soap or put it in the washing machine. This can reduce the effectiveness of your mask by stretching or misaligning the material. The mask may still look fine, however the effectiveness is reduced. Many filter materials listed below are non woven. We will talk more about that below.

Masks made of cotton and filters can be washed through a machine. Use high temperature water and soap. Do not boil for a long period of time, however very light boiling is fine. Do not use bleach on any mask, it can deteriorate the fibres. Remove the nose piece and make sure to dry high temp in a dryer.

To disinfect your mask, you can use alcohol spray but this cannot 100% guarantee that all viruses are killed. Spray the entire mask sleeve thoroughly. You can also microwave the mask for 2 minutes at 600 watts, just make sure to remove the metal nose piece. There is also some evidence to suggest the virus (much like MRSA and SARS) can be killed by being exposed to UV-C light, so you can leave it in full sun, however this has not been tested with COVID-19 at the time of writing this. Regular UV-LEDs, such as nail lamps, do not sterilize.

Putting your mask (woven, or non woven) in the oven at 70ºC/158ºF for 30 minutes will also sterilize your mask according to Stanford Medicine (2020)?***

There is some evidence to suggest you can leave the mask in a dry, untouched place for at least 4 hours, however there are also suggestions that COVID-19 can live for 2-4 days. There is no way to be certain at this time. This depends heavily on the material. Surfaces like metal, vinyl, or plastic can be wiped clean. Surfaces like fabric dry out viruses.

If you are using a filter in your mask, some may be washed and reused. Filters such as furnace filters or coffee filters, paper filters, or felt filters will not be as effective (or effective at all) when washed. Do not wash your furnace or felt filters, however you can put them in the oven to disinfect.

Medical sterilization methods:

If you are making masks that are to be used in a medical context consider their sterilization method. Some hospitals use an autoclave, which gets heated to 121°C (250°F) to kill bacteria, and some use high temperature cleaning methods, which can damage elastic. Elastic material often does not last long, as well as some synthetic fibres. Be aware of what your materials are made of and their heat tolerances.

Salt barriers^[a]

You may choose to not use a filter in your mask for breathability or lack of materials. Your mask is still effective! You can also use a salt barrier procedure daily on your mask cover or some filters.

Salt in the path of a virus will kill the virus, and this may improve air filtration efficacy due to forces keeping water away and will improve the sterility of the mask. Dish soap can improve the reach of the salt into materials. This should only be used on cotton or woven mask covers or filters, not on non woven materials because the process might damage the material integrity.

This procedure can be used daily.

• Fill a pot with water, distilled or pre-boiled is ideal but any potable water is fine
• Water can be optionally heated up to about 190f (light boil) so as to improve salt solubility and overall saturation of the solution with salt
• Add salt until the point of saturation (undissolved salt accumulates at the bottom of the pot after stirring)
• Add drops of dish soap until the solution becomes very foamy
• Add your cloth filters, stir, soak for ten minute and then let dry

Material choice:

We advise using 100% tight knit quilting cotton for exterior and waffle weave “tea towel” cotton for filter, both are fully washable. However, you can substitute or upgrade materials.

Material choice is critical to the construction of any PPE. Masks filter by trapping particles, but should also be breathable. Furnace filters are effective at letting air through while trapping particles. You should also be mindful of your breathing making your mask wet, which could increase risk of bacterial growth. Choose the best material you have available, while keeping in mind how the material choices affect your mask.

Masks may have an optional middle pocket for an additional layer of the filter. Doubling the layer doesn't necessarily mean doubling the effectiveness of the mask, however the mask has at least a 2 ply layer. Some filters need to be discarded if they are likely to hold onto droplet particles. If your filter is wet after use, discard it if it is not washable.

You can choose to upgrade your filter or make your own mask with the filters listed below. The most effective easily available filter is a HEPA filter, rated as merv 17-20 which removes at least 99.97% of airborne particles. You would most likely to find merv 11 furnace filters, rating between 13 and 16 capture particles 0.1 microns (the size of COVID-19) however lower grade filters are also somewhat effective. Merv is the rating system used to describe air filters (details here). While the virus itself is smaller, it is primarily transmitted through droplets. Other filters can be made with non woven materials (such as felt), however these should not be washed or they will reduce effectiveness drastically. The chart below is only a rough gauge. It is important to understand that quality of fabric, thread count and tightness of weave/knit can heavily impact the viability of the filter. This list is not definitive and can vary hugely between two variations on the same material. Select a tighter cotton for the exterior of your mask if possible. Polypropylene is also effective as it is hydrophobic.

The following materials make effective filters, however, each may be different based on brand and quality.

• Vacuum cleaner bag
• dish cloth/“tea towel” / waffle weave cotton
• 100% cotton shirt / quilting cotton
• “Non-woven” material -  cloth found in rags, diapers, gauze, wet tissues, tampons as filters too. May not be suitable for multi use. Non woven material can be damaged if washed normally, even if it looks the same.
• CSR Wrap (Reusable Surgical Wrap)
• Reusable fabric shopping bags w/ cross-hatch pattern
• Polypropylene
• Microfiber, soft, woven polyester made of textured yarn (do not have a shiny, stiff appearance, and that look and feel like cotton).

Woven/Non woven materials: Non woven materials are neither knit nor woven, they are made from fibers bonded together from heat, chemical, or mechanical (bunched up or matted together) means. Felt is a common non woven material. You can look closely at a fabric and see whether it is woven, knit, or nonwoven. Nonwoven materials make for effective filters, but are generally non washable.

Tutorial

Find scaled .PDF template download HERE. If you can’t print them, you can download, set size to 100% and trace the outline.

Materials:

• 100% Quilting cotton. We suggest using a light color in order to see if it dirty.
• Waffle weave “dish towel”
•  20” Elastic or Cotton Ribbon tape (can be 1/8”-1/4” wide)
•  2” pipe cleaner/bendable wire
• cotton thread
• Nose piece (Pipe cleaner, paper clip, craft wire, or similar)

Equipment:

- home sewing machine or straight stitch machine - serger/overlocker (optional)

- scissors

- pins

- pencil or disappearing ink marker

Step 1: Cut out all materials. Fabric must be 100% cotton for the mask components, while the filter components should be 100% woven waffle weave cotton. Do not use any synthetic materials as these are not CDC compliant.

Step 2: Place both outer mask pieces of cotton good sides together. Sew the curved seam from top edge to bottom, repeat for lining pieces.

 Step 3: Using an iron, press curved seam allowance to one side on both lining and outer layer center seams.

Step 4: With seam allowances pressed to one side, top stitch down seam allowance through all layers about 1/8” away from seam.

Step 5: Stitch the filter curved seam the same way as both the lining/pocket and outer layers of cotton. This time, sew at 1/4” seam allowance. Press seam allowance to one side, and top stitch the seam allowance through all layers 1/8” away from the seam.

Step 6: Hem short edges of pocket/lining piece of mask. Finish each end of the mask with a 1/2” turn and turn hem.

Step 7: Lay outer layer sewn piece of outer mask right side up. Lay finished lining/pocket piece of mask wrong side up on top of outer mask, aligning center seams. The outer mask will have 1” of seam allowance overhang. Pin and sew along top and bottom edges creating a tube. Each seam will have 1/2” seam allowance.

Step 7: Carefully clip into 1/2” seam allowance as needed and turn work right sides out.

Step 8: Finish the short edges of the outer layer of mask with a 1/2” turn and turn hem. Fold hem towards the inside or pockt/lining side of mask. Be careful when stitch hem not to catch hem of pocket/lining as this is where the mask filter is inserted.

Step 9: Create nose piece pocket. Using a ruler, measure 1” from each side of center seam in the mask and pin. Top stitch 1/4” along the edge of the mask through all layers, between pins, back stitching at beginning and end of stitched line.

Step 10: Using tweezers, insert 2” piece of pipe cleaner or bendable wire into nose piece pocket and bend slightly at seam into small peak. At this time, also insert the mask filter into the pocket of the mask, smoothing any wrinkles.

Step 11: Attach the elastic/ribbons. Start by cutting your elastic/ribbon in half (you should have

two 10” pieces). These can be attached by threading each piece of elastic/ribbon through each hem of the outer layer of the mask using a safety pin. These pieces can be adjusted in length to either fit around each ear of the wearer or to tie behind the head of the wearer.

Science:

How long can COVID-19 survive on surfaces?

Copper: up to 4hrs

Cardboard: up to 24hrs

Plastic & stainless steel: up to 2–3 days

Air: up to 3hrs (but most often less time)

Clothing and cloth can hold respiratory droplets under daily use. These particles can dry out over time and this can kill the virus, but it may not happen quickly. Different fabrics alter the time a virus can survive. Porous materials potentially catch, dry, and break apart virus particles, while smooth surfaces like vinyl or leather can be wiped clean. Spandex and polyester may retain particles longer than breathable cotton, and details like metal and plastic buttons, zippers, or other hardware may hold onto viruses longer—up to 2-3 days.

        Careful handling and washing is important. Use the hottest possible washing temperatures suitable for the article of clothing and add additional time and heat when drying. Do not boil clothing as it will damage the fibres and potentially ruin them.

How big is COVID-19?

Coronavirus virions are spherical with diameters of approximately 125 nm. Single-use face masks and surgical masks typically capture large particles that are 0.3 microns in size; these can include vapour, droplets or water particles, which is how COVID-19 is commonly transmitted. Respirators like the N-95 can filter smaller, 0.1-micron particles, which is the size of a virus. In a normal situation, if the mask is being used for pollution, the effectiveness of respirators declines only marginally with regular use. However, in our use case, we are worrying about viruses.

If you are more than 6 ft away from someone, your likelihood of transmission is very low. You may also be worried about infecting others—whether COVID-19, cold, flu, or other illness—in which case, a percentage of the particles will be filtered depending on the mask material. In this chart, we can see that the amount of ambient particles smaller than 4 microns at 6 ft is very low. There are still some larger particles, which should be filtered by most masks.