Two liter soda bottles are made of clear plastic to show off the product. They're pretty robust, surviving shipping while internally pressurized to ~30psi with very few scratches, and are readily available in convenience and grocery stores.
Given reports of ongoing shortages of face-shields for personal protection, we realized that a clear 2L bottle could be adapted into a face shield in ~10 minutes; see our design at GitHub and below. Now, we have no particular competency at designing face shields but if anyone is facing a need for a face shield, this design is highly accessible.
The key feature is the use of the bottle's curvature to grip the forehead and to close the mask below the chin, as below. It lies close to the face, with room for a close-fitting mask, but larger respirators are unlikely to fit. As I've worn it air is limited to flow only around the chin, the close-pressing sides and complete forehead contact prevent flow through the top or sides of the shield. Visual distortion is noticeable below the waist-level, anything held chest-level and above will be clear.
We would appreciate feedback or commentary from practitioners and would love Pepsi, Coke, or independent bottlers to join in meeting this need. If you know people in the medical community that may not have sufficient protection, send them a link. Stay safe everyone.
— Ben Conrad