This is a fully 3d-printable respirator design requiring minimal materials to make. Check out the thingiverse page for it: https://www.thingiverse.com/thing:4258947

Note: this design is not tested, use at your own risk.

Supplies

To build it, you will need a 3d printer(kinda obvious), at least 15m of filament, TPU(or any other flexible filament) and PLA. Also, it requires wool/cotton/makup pad for the filter(or a real filter if you have some).

Step 1: 3D Print the Parts

For the first step, print the parts. Use your flexible filament for Mask1.stl and PLA for Mask2.stl. You may need to scale the parts in order to fit your face. If you do not have flexible filament for Mask1.stl, you could tweak the settings in your slicer to vase mode, so that only 1 perimeter is made, thus making it more flexible.

Step 2: Assemble the Filter

Take your filter material and fit it in Mask2.stl. Make sure it is not too tight, nor too loose. If it is too tight, you could have difficulty breathing. If it is too loose, it could be ineffective.

Step 3: Make It Comfortable

Take your wool or cotton and glue it around Mask1.stl to make a good seal. It also makes the edges more comfortable on the face. Also, tie an elastic band into the two holes.

Step 4: Assemble the Parts

Take the two parts and screw them in. Make sure to glue it in order to make a good seal between them.

You are done! Make sure the glue has dried before putting it on your face(it got stuck on mine... XD)!