Healthcare Engineer Explains Fitting a 3D Printed Montana Mask for COVID 19

I describe my process for fitting the Montana Mask found at www.makethemasks.com.
These masks are widely accepted by nurses at Long Term Care facilities and are useful for the general public to save the N95 masks for the heroic healthcare workers directly facing COVID 19 patients.
More fitment instructions here:
docs.google.co...
I did modify the design of the Montana Mask to increase the tie loops. A few simple push/pull commands in Fusion 360 allows you to do the same.
The clasp I designed can be found here:
www.thingivers...
I use rubber or EDPM weatherstripping to generate a seal. Replace as needed when cleaning/sanitizing the mask.
I describe my use of clasps for using rubber bands or other elastic bands. Use elastic if you can find it. I demonstrate rubber bands as a temporary solution and they snap me a few times.
I use a furnace filter with a MPR1900 rating, $20 at Target and good for a few hundred masks.
Go make a difference, print for those that cannot, and keep hope alive!

[@LT72884]

I am a medical engineer as well. I actually designed a mask that prints in 2 hours and has a cover to go over the filter. One fyi for all, you can sanitize the filter material by baking it in your oven for 20 minutes at 170F. Do NOT use water or ipa with the filter. They are electrostaticly charged and due to the type of dipole bonding that ipa is, it will cancel the charge, and water will just short the charge out. Using ipa on the pla is best option for sanitizing, besides hot water and soap, due to its inherently low surface tension. This allows it to actually get into pores smaller than viruses. A friend of mine is required to use rubbing alcohol for the filters they make that filter out viruses from blood. Today, i did some tests with silicone caulk aroumd the edge and it worked very well. I have also made a mold of my mask so when the time comes, i can cast them in silicone or resin haha.

[@richardvedvik979]

Awesome input!

[@1234fishnet]

I'm a engineer for medical equipment in Austria. I did exactly the same thing without watching your video. This mask is for my friends, I used a full face snorkeling mask with a 3D printed adapter and a HEPA 13 filter from my vacuum cleaner

[@RyanKelbel]

Richard, I know this is 2 months old, but do you have any specific recommendations on furnace filters within that rating MPR1900 that you know for certain do not contain fiberglass? I would like to do something like this, but I know that has been a concern when I've heard a discussion of using furnace filters. I wasn't sure if you had done research on that yourself. Thanks for you help in advance!

[@richardvedvik979]

A natural fabric layer on the inside (thin, sheer, fabric) can help catch any loose fibers from the filter media.

[@grantching2567]

@Richard Vedvik, thanks for the video. Are you concerned that the seal between the plastic filter insert, filter material, and mask can be compromised by the bunching up of the filter material, particularly in the corners?

[@richardvedvik979]

Yes, we are certainly concerned with the filter installation. A properly fitting filter is important for a firm fit of the frame. The filter media has seemed to fold fairly easily without bunching up, i suppose that it stretches a bit when installed. The filter window is held in place by friction from small bumps, meaning that the filter window frame leaves some room for the filter media to pillow between the bumps and corners. The result is a fairly flush and smooth appearance from the outside and what appears to be a good fit. We can see from the Montana Mask testing on their website that when subjected to the NIOSH standard test method the mask and filter window arrangement passes.

[@grantching2567]

​@@richardvedvik979 , thanks for the reply. I actually have two of these Montana masks made from PLA and got concerned when the plastic frame insert popped out when I inhaled (it hadn't previously done that). I added an extra sheet of blue shop towel, which seemed to work but became concerned when I noticed the corners of the filter material seemed a little more recessed (looking from the outside of the mask). Last night, however, I was able to do a homemade test using a Harbor Freight IR thermometer. Temperature measurements of the filter material at the center (when exhaling) were several degrees hotter than measurements taken of the filter material at the corners (when exhaling). Not super scientific--but good enough to be reasonably confident that there's probably minimal leakage in the corners when inhaling (movement of the filter between breaths was minimal to none to the naked eye).

[@donniefontaine8018]

Thanks for posting this. Please consider posting your modified mask to Thingiverse and post a link to it.

[@bernardoflores1832]

How often do you change your hepa filter? Its last 3months on your furnace before you need to change it out. Is the same on the mask?🤔

[@richardvedvik979]

I've been swapping filter media based on usage and exposure. If I was around a lot of people i'd swap it after that day. One home filter makes a few hundred squares.

[@larryrichardson5167]

I saw that bungie cord inners are the elastic

[@richardvedvik979]

Good call. My shipment on elastic finally arrived but rubber bands did the trick for months and were easy to swap out or clean if needed.

[@Masterdebator881]

Oh wow, now how are you going to prevent the boogeyman from entering your body through your eyes, ears, and skin? Do you have an experiment that proves your mask is capable of preventing the boogeyman? Link please!

[@richardvedvik979]

Both boogeymen and boogeywomen are quite determined to enter any face hole that has porous absorption (skin is fairly resistant because it has sub-atomic superheroes on the surface playing red rover). The face hole that generates a vacuum tends to act like a worm hole for boogeypeople. Because the boogeypeople have a characterized size, the MPR rating of filter media (made from the fine strands of hair from woodland fairies) is accurately tested for percentage of blockage - measured in micrometers - or 0.000001m resolution. MPR1900 and higher is suitable for viruses and the percentage of particulates captured is well documented for each filter type. The links in the description also discuss this and the first link includes testing results compared to an N95. Regardless of the idea or belief surrounding mask usage, herd immunity, or natural selection; it is undeniable that our healthcare facilities will be overloaded. We don't design hospitals to allow every room to be negative (maybe one in twenty or one per floor). While that will likely change moving forward, the current situation is that contagious patients are exposing the entire facility. PPE within the hospital is necessary to maintain health of the workers. My immediate family are working in hospitals and are re-wearing the same N95 masks for days or weeks while treating COVID positive patients. Anything that reduces the public's use of those masks is helpful. Nursing staff at Long Term Care facilities have expressed concern they may quit and abandon the residents if they don't get masks/filters that make them feel safe, and these masks provide that both functionally and spiritually. Many LTC facilities aren't receiving PPE due to hospital shortages getting priority. The general public is being directed to wear cloth masks, which doesn't have anything close to the performance of a properly fitted respirator with proper filter media. None of this is ideal, and most of this is worse than that, but our nurses and doctors are needed, so action is required. Because the public will be required to wear masks in public very soon in most areas (rural or urban), I think the mask should be as effective as possible without depleting a resource required by healthcare workers. Cheers.

[@Masterdebator881]

Richard Vedvik Problem is, you are trying to protect against something that doesn’t exist. Check out Andrew Kaufman.

[@Keystone19]

Truth is Freedom Florida Show me proof and hard facts. Not just someone putting a bunch of words together showing how ignorant they are. I will wait.

[@Masterdebator881]

Keystone19 Proof of what?

[@richardvedvik979]

@@Masterdebator881 I design hospitals and interact with hospital personnel daily. I do have first hand knowledge of how hospital systems are reacting, testing, and being impacted. There may be global manipulation to usher in the NWO, since the entire planet reacting fairly equally (which is odd) and the devaluation of currency. I totally acknowledge that this is a very odd reaction. IMO - if we really cared about saving every life we wouldn't allow abortion. But the population is being told to wear masks, and nursing personnel are also being told the same. I make these for people that ask for them, and they will be handy respirators for future woodworking projects.