Printing the mask?

Download and see in-depth requirements for safe-usage here

Please see the most up-to-date description and video here

It's a printable mask for my Sister. She needs PPE and there isn't enough for her. Her hospital will likely be getting hit with a wave of patients very soon. Significant amounts of people hospitalized are dying and the number would likely worsen with the fewer doctors and nurses available. Community-sourced cotton and other materials work, but not nearly as well as real filter media, like what is used in this mask.



Dear Sister,

I have been keeping up through second-hand sources – you’re married, birthed twins, and are working as a doctor in a hospital just outside of Los Angeles. When your flight was to arrive this weekend, I hoped we would have been able to not only celebrate your kids’ first birthday, but also reconnect and catch-up about… virtually our entire lives – ever since you left for school.

Alternative to our long-overdue family reunion and seeing Disney’s Mulan, what you’re dealing with now is that your workplace may soon become overrun with patients. The environment is likely to be panicked, loud, and highly infectious – especially since you’ll be intubating the sickest to allow them to continue to breathe and receive ventilation. Intubation and its preceding steps are, according to The Lancet, some of the highest-risk moments for COVID-19 spread to healthcare workers.

You’ve expressed your anxiety about how your hospital is already short of PPE (personal protection equipment). I believe the shortage is a disgrace. The sewn-cotton community mask donated to you is already hardly enough to even protect against respiratory droplets generally expelled by coughs and sneezes. What chance does cotton have to block aerosolized COVID-19, its many-times-smaller form? The same form in which the scarce N95 and better material is specifically designed to take care of.

Fortunately, HEPA filters happen to be virtually perfect for Coronavirus particle sizes. They are rated higher than N95-material and are at least as good as N100 specs. They’re also in-stock as furnace filters at Home Depot (well, they were, hehehe). I have drawn up and tweaked a 3D-printed mask for you that will work using small squares of the filters cut-up. The seal around your face is important – you may need to add more foam where it meets your face to ensure it seals correctly for you. The filter seal is spring-loaded and should maintain its integrity. You should be able to swap-out the cotton and pre-carbon filters, all of which are pre- and post-, to extend the HEPA material’s life. I am mailing you pictured mask tomorrow morning and will mail you more, with revisions, this week.

Be careful of what you read and hear, even other doctors may mistakenly believe that filters work like a net, and that if a filter couldn’t capture a 0.3 micron particle, then it couldn’t catch anything smaller. That is not true. Read about diffusion and the link below from 3M that describes a little more into the process of how these particles are caught. It is also helpful that we maximize the surface area of the actual filtration material since it better catches the particles when the air flows through it at a slower velocity.

Stay safe.

We’ll see each other again next year.


. .

. Sources:

Helpful tips for safe intubation and other practices, from Hong Kong hospitals

Respirator information from 3M

Hepa Efficiency NASA study

HEPA Efficiency Article

Base Montana Mask (based mask off this one, for the curves from the 3D-scan of Dr. Richardson’s face. Mask currently undergoing verification by a group associated w/ Harvard Medical in Boston)

Copy-paste from above link:

The 3D printed mask information presented here is intended to assist the general public during the current a global pandemic related to COVID-19 and the related nationwide shortage of personal protective equipment. Please be aware that this mask design is not intended to replace standard protective equipment such as N-95 masks or surgical masks when that equipment is available. The use of these 3D printed masks has not been fully tested and has not been approved by federal or state authorities.

Built With

Share this project: