A quick-printing (sub 10 minute) skeleton mask to pair with a roughly 7" x 8" piece of filter material and elastic bands (daisy-chained rubber bands work), PETG or PLA - may work with flexible filaments but have not tested.

 

Designed to print with a 1mm line width (.5mm works also) and a .25mm layer height.

The entire print should print as walls, there should be no infill or skin.

 

Attach straps by tying knots in the end, start loose and tie additional knotes for a tighter fit. Also works with daisy-chaining a couple rubber bands together.

The fit should be below the chin. Lay the filter material against the frame, then pull onto face with the elastics. You can bag the filter material out a little bit to give your nose and lips some room, then fold the excess material above the mask under the internal 'ring'.

Due to the sizing of the filter material I have access to, I've been using about a 6" x 8" piece of filter material. A wider piece (7" x 8") would be better.