This document is also available as a PDF here.
This DIY device provides N95 or better filtration without covering any part of the face for a fascist mask ban to object to. It is based on a CPAP nasal pillow headgear unit and requires the wearer to breathe in thru the nose and out thru the mouth, which takes a bit of practice but has advantages over Version 1’s oral air supply route in that it permits speaking and eating while still breathing filtered air. Besides defeating mask bans, this device is also useful for eating meals in crowded places like schools or airports.
A disadvantage of this device is that it may be difficult for users with a constricted nasal airway, eg: deviated septum. There are breathing aides such as Breathe-Right adhesive strips that may be necessary for users with a constricted nasal airway (see notes).
The 3D print file can be downloaded from ProtonDrive here.
Parts List:
Rio II CPAP Nasal Pillow unit $55 (purchase link)
3D printed BPR adapter $15 (online 3D printing service)
1 pair filter gaskets $5
1 pair 3M compatible respirator filters $5
Total Cost $80
Instructions:
CPAP unit:
The instructions here are for the specific CPAP unit linked above, the Rio II, but the BPR adapter is sized for standard CPAP hose and will work with any CPAP headgear unit you choose. There are tons of different styles available, just search for “cpap nasal headgear”. I chose the Rio II because it was the cheapest nasal-pillow type unit available at the time.
The Rio II comes with 3 sizes of nasal pillow, select whatever size fits your nose best. Pull the hose off the headgear and start sealing up the swivel unit to make it airtight. There are holes on the top of the swivel that need to be taped over. I used white medical tape, but of course you can use anything to cover these holes. Next you need to seal the swivel joint. I did this by pulling the 2 pieces apart and putting plumbers putty inside, then pressing the 2 pieces back together. It was extremely difficult to get them back together so I don’t recommend doing this, especially if you don’t have good arm strength. What I recommend is using kitchen/bath caulk and placing a bead of caulk all the way around the swivel joint. If you want to change the orientation of the swivel later you can peel the dried caulk off, reorient it however you want, and then re-caulk it.
Take some time now to test the nasal pillow/swivel unit on your face for an airtight seal. Cover the air intake opening with a piece of tape and try to breathe in. If the unit is sealed properly you should be unable to breathe in. If there’s air creeping in somewhere, find where it’s getting in and seal it up with caulk or tape. Take your time here, once everything is finished it will feel like there’s very little resistance, this test phase is where you will build confidence that it’s properly sealed. Once you’re satisfied that the headgear swivel unit is getting a good airtight seal to your nose, then go on to the next steps.
Connect the hose to the nose unit, and insert the other end of the hose into the 3D printed adapter. Depending on the printing quality, you may need to do a bit of sanding on the interior surface to get the hose to fit. You can see in the pictures below how my 3D printed adapter has flat spots, I sanded these down with 150 grit sandpaper until the hose fitting could press in smoothly.
You’ll notice that this hose connection is not airtight, you’ll need to seal this up with plumbers putty, caulk, glue, tape, or anything else you want to use to achieve an airtight seal.
Put a pair of gaskets and filters on the adapter and you’re done. There are loops on the adapter to add a string or cord for wearing it around the neck, so there’s no weight pulling on the nose unit. Congratulations, you now have an N95 air supply that can’t be taken away.
Printing an adapter:
I don’t have access to a 3D printer, so I used the cheapest online 3D print shop I could find, and the cheapest materials options. It came out fine, just needs some smoothing with sandpaper. You don’t need access to a high-end printer for this. If you, or a friend, have a basic 3D printer it should probably be able to print this.
If you don’t know anything about 3D printing, that’s fine. You don’t need to open the file or do anything with it. Just choose an online print service and upload the .stl file, they will print it and mail it to you.
The folder linked above contains 2 files:
[BPR_v2 (Meshed).stl] is the printable file. This is the file to send to the printing service, or to your friend with a 3D printer.
[BPR_v2.FCStd] is the FreeCAD design file. You only need this if you want to make changes yourself. After you make changes you will create a new meshed .stl file to send to the printer.
Gaskets:
The filter gaskets are the most annoying part of this project. The orange 3M gaskets are very overpriced and typically only available in large quantities, you can sometimes find them on eBay in small quantities, but often still very overpriced. The part number to search for is “3M 6895”.
To save a few dollars I used 1/8” neoprene foam from Amazon and cut out a pair of gaskets with scissors. Inside diameter is about 21mm, outside diameter is about 37mm. You can probably find similar material at any hobby or crafting supply store. The 1/8” neoprene foam I used worked okay, it’s a bit thin so I ended up using a double layer which is super tight but I felt better about the quality of the seal. I recommend not using adhesive backed foam, it makes a mess when removing/replacing them. I also considered just gluing the cartridges onto the adapter with plumber’s putty or kitchen/bath caulk. There are plenty ways to cheaply seal the filter cartridges to the adapter, all that matters is that air can’t flow between the mating surfaces of the filter cartridges and the adapter, so use whatever material is cheap and easily available for you.
Filter Cartridges:
I duplicated the filter attachment from a 3M 6000 mask. I’ve only tested the adapter with brand-X knockoff filter cartridges, but it should work with any 3M 6000-series compatible filter cartridge.
Notes:
Nasal Dilators:
I have a deviated septum that makes breathing thru my nose very difficult even under normal circumstances. I am not able to use this device without some sort of nasal dilator. I tried the Walgreens brand knockoff of Breathe Right strips and these work great. I also tried the more expensive Silent Mammoth metal wire nasal dilator and while it works great for normal use, it unfortunately prevents the nasal pillows from getting a good seal to my nose so I am not able to use the Silent Mammoth in conjunction with the Ban Proof Respirator.
Version 1:
This is the second version of the Ban-Proof Respirator. The first version is still available here, but I think V2 works much better and I don’t recommend using V1 unless there’s a compelling reason, for example if you’re simply unable to breathe well thru your nose.
