Originally Posted by
homonculus
I may be missing something, but how can a piece of plastic, whether made at home or from a supplier, stop a virus???? The link has a reusable respirator with one filter replaced, which raises all sorts of issues as to its efficacy. There is a company making an internal mic for the 3M half face systems which, if properly fit tested appears to work, but is anyone doing a formal fit test on these devices in both the static and dynamic mode?
I must have missed the bit about stopping the virus, it wasn't mentioned prior to this, under the impression the OP wants to build a face shield/maxilliofacial shield?
I'm told the respirator in the link with one filter removed is fit testable, and in use with several air ambulance operators. They also offer an alternative Gentex respirator tested with the Alpha helmet.