Anti-Fog Face Shield Tricks
- Fogging of transparent glass, plastic or composite materials is caused by differences in temperatures between the two sides of the shield. A cold outside and warm inside causes water vapor from your breath to condense on the cold shield, especially in wet or cold weather. In hot weather the shield can be warmer than the air inside the shield and so no fog forms inside. Some helmets or goggles have vents in place to improve circulation inside the shield and reduce the temperature differences between the inside and outside of the shield. This can help reduce fogging some all by itself.
- Scuba divers have the most pronounced fogging problem because the outside of their face shield is in contact with cold water while the inside is next to a warm moist face. Divers early on discovered that if you spit on the inside of the mask, rub it around on the plastic faceplate and then give it a quick rinse, the mask won't fog for an hour or so. Another substance that does the same thing is liquid dish soap. You can, of course, buy commercial anti-fog preparations at the dive shop, but most amateur divers don't bother, so effective is human saliva as an anti-fogging solution.
- Bikers use a simple bar of wet soap rubbed on the inside of the face shield. Rub the soap on, then wipe it clean and buff it clear with a paper towel. Dishwashing soap works in the same way. You can also rub a potato, apple or pear on the inside of the shield and then wipe clean. Potato works best. Shaving cream works if you spray it on and then wipe clean with a clean soft handkerchief, paper towel or newspaper.
- Various bathroom and kitchen cleaners will reduce fogging, but those with bleach or ammonia can cause your eyes to sting if your face is close to the shield. Some furniture cleaners work as an anti-fogger, but you'll have to experiment to see which ones don't leave a hazy film on the glass. Plastic cleaners and glass cleaners may help reduce fogging, but again, chemicals in the sprays may cause your eyes to burn so test them out first before you use the shield.
- Commercial solutions include inserts that create a second insulating layer to reduce the temperature differential between the inside and outside can be bought at cycle shops. Permanent chemical treatments that can be applied to the surface of the shield are also available at cycle and dive shops along with temporary anti-fog solutions that are applied immediately before you ride.