Face shield fogging in the rain

[Stig / Major Tom]

I've tried applying various products to the inside of my face shield, but even with the pinlock in each of my helmets, I found that the only foolproof way to prevent the inside from fogging is to keep my face shield slightly cracked open.
I've applied a small bit of 3M body tape to the bottom of my face shield  - this blocks the shield from closing completely on my full face modular helmets. Just that small bit of venting works to keep down the fogging.

Just recalled that there was one time when things were so bad that I turned around and rode home.
One night ride about 2 miles from home I rode my Forza into the thickest fog I'd ever seen.
I'm not sure that I could see 3 car lengths - and new that a following car would hit me before they ever saw me....so  home I  went.
There was one time during my dark morning work commute on my LIKE200I that a fog and mist situation blocked my face shield so bad that I tried riding with my helmet open. But the mist soon covered my glasses!!..so I put them in my pocket and rode 4 miles to work by following the Yellow center stripe! My vision without prescription glasses is that bad🙃
Stig

[Neil955i]

I can recall some hairy commutes during my working life and all the worse ones related to vision, or lack of!  Fog invariably causes problems with the visor (and mirrors) and like you I've had to ride big chunks of my journey with the visor up to be able to see safely - fortunately my vision for riding is absolutely fine without glasses.  As an aside my optician told me last month that my unaided vision comfortably exceeds all the DTp requirements for driving so there's at least one bit of me that still works!

Can't vouch for fog, but since using pinlock antifog shields, I've never had one fog up on the inside, even with the visor locked shut.  I think they're brilliant. 

A memory, anyone else recall full face helmet breath guards?  A foul rubber device to direct exhaled breath down and out of the helmet?