I would be concerned with the penetration qualities, or lack thereof, of a 2 liter bottle type of plastic.
I believe one of the sayings we have at work is: The road to safety was paved in blood.
I wouldn't recommend modifying or changing safety equipment. When the useful life of a product is over, discard and replace.
What is your price for safety? Ask yourself, how many eyes can you live without? Maybe it won't happen to you, maybe it will? Feeling lucky? I've seen too many accidents and had too many myself to want to chance it any more. I won't post the more gruesome face shield accidents I found!
