This is a filter remix of the Montana Mask attributed to the Billings Institute by an upload made by KLambert to the NIH 3D Print Exchange: https://3dprint.nih.gov/discover/3dpx-013312

The face Mask part is pretty good, but the insert for the filter was incomplete and incorrectly sized.

This post includes the facemask component from that post as well as my own design for the filter holder inserts.

The inserts are designed for both cloth as well as a more rigid filter material. It is in 2 parts with an inner part that fits into the outer part. Keep in mind the tolerances can be tight, but I tried to size for cloth use.

The filter material is up to you, but from what I have seen looking around online one can use the cloth from a 100% cotton T-shirt. This design allows for 2 layers as well as an included rigid part if you can find some filter material.

It can be printed in PLA or ABS or PETG, but I printed the face mask using TPU. TPU flexs and makes for a good fit with a good seal. Any kind of rubber band material will work for straps. I found it is way more comfortable with some stick on Moleskin in the nose area on top. The filter inserts I printed with PETG but any rigid filament will work.

For more discussion on this thing as well as a wide range of other 3D Printing related topics check out my podcast: 3D Printing Today. There's NO advertisements. It's free, we do it for folks like you for fun and not for profit.

Threedprintingtoday.libsyn.com

Or look up "3D printing Today" wherever you get your podcasts from.