After seeing some 3D printed masks, I was inspired to make a simple one that could clip onto the brim of a baseball cap. It turned out to be a very lightweight transparent barrier that can prevent spray from reaching your face and prevent your spray from getting on someone else. The 3D printed frame simply clamps a photocopier transparency in a curved shape and clips it to the brim of a hat. You can also wear a filter style mask under it, if you need more protection.
It fits differently on different hat brims, but it can be positioned reasonably on most of them....
Flatter brims work better with this design....
Here it is on a Med-Eng cap
Here it is on an element14 cap.
If you want to try this build, there are 3 .stl files in the attached .zip file.
One file is the curved rail that everything mounts to.
One file has the two clips that attach the rail to the cap brim.
One file has three small clips to attach the transparency to the rail.
My other ideas for fighting viruses are here: