EXPERIMENTAL ONLY
This is a modification of the 'Montana Mask' found here:
https://www.billingsclinic.com/foundation/
Full credit is owed to what was done. An outstanding job was done with the original design.
Video with info (in English): https://youtu.be/35QjGBDAL2M
There are 2 versions of the mask, the video above only shows the first.
The first version, V1, uses any kind of cloth-like filter media you can source that is appropriate. There are 2 retainers, each giving a different amount of gap between the retainer and the mask. The lower portion of the mask itself (where the retainer spherical detents are), if printed in TPU, should be solid for rigidity. They can be at low infill with ABS. Filter media should be the best you can find that will allow enough air flow. I am thinking HEPA filters from vacuum bags or furnace filters. Use new of course...
Cut your filter media to cover the front of the mask and overhang, so it gets "tied in" with the spherical locking tabs. The spherical locking tabs will actually pull the filter media tight over the mask. Of course, I included f3d files so you can make mods needed.
The second version is designed to accept 3M 5P71 filters, which are P95 rated. Of course, you can use other filter media cut to the proper shape. You may have to add compression material or modify the files to make sure you have a squish of the media against the mask. Since you cannot simply scale this mask to fit a smaller head, such as for women, and still use a standard 3M filter, I have included a version where the mask has a 90% fitment, but the filter area is the same. The retainer is universal. Again, source files are included for mods you may need.
Masks has been tested with, and can be printed in either ABS or 95A TPU. Retainers should be printed in ABS for rigidity. The reason for ABS is to allow sterilization by a boiling water bath. TPU will conform to the face, and it will also withstand a boiling water bath for sterilization. Make sure you test a sample of the flexible you are using, there are a LOT of versions out there!
This is still a work in progress, and is for experimentation only. This should NOT be considered proper PPE or as a replacement for a proper protective apparatus. USE AT YOUR OWN RISK!!!!!!
This design is non-commercial licensed. If I find them on eBay for more than manufacturing cost, I will have it shut down.
NO SUPPORTS
The author hasn't provided the model origin yet.