By the spring of 2020 I was unsure what the future held and what to expect when around others. N95 masks were impossible to come by as were N95 inserts for respirators. However HEPA filters were available for purchase and theoretically remove 99.73% of particle with a size of 0.3 microns compared to the 95% provided by an N95.
I found a manageable size filter online and then proceeded to create a box that would surround it. I them modeled an adapter for the other end of the box to fit on my painting respirator. I created a 3D model of the bayonet end to mate with the mask and 3D printed a prototype. After making a few tweaks and lofting the two pieces together, I exported the model for use with my 3D printer. I printed the piece and used a thin piece of rubber as a gasket.
Exterior of the box being built up and support material is seen on the interior.
Filter box fitted to mask and snap cover used to hold filter in place.
Respirator with HEPA filter adapter and block-off cap for other side.