I wanted to use my RZ dust mask as a "medical" mask, but the fact that exhales go straight out the vent defeat the purpose. I made up some plugs just like the originals but with no hole for the vent. They seem to seal pretty well and force the exhale back through the filter.
I've also added a plug for a generic look alike mask here. This had the threading reversed with the inside plug having nubs that engage with the outside vent. This plug has a diameter of ~ 19.5mm.
Generic_Plug.stl | 5.4MB | |
RZ_Plug.stl | 6.0MB |