9 years with NASA as an engineer, this guy shows you how to quickly defog your windshield, and why it works. It doesn't work for frost on the outside of the windshield, of course, but it will work on frost inside the windshield, it'll just take a little longer than simple fog.
A few words on kitty litter...
Near the end of the video he shows you how to use kitty litter in a sock on the dash to help prevent fog in the first place. One, you need enough socks to go all the way across the bottom of the windshield. One sock won't work, you need 5 or 6. Two, I think the brand in the video is Fresh Step. It doesn't have to be Fresh Step, but it can't be just any ol' kitty litter. It MUST be 100% silica gel kitty litter. 100% silica gel kitty litter is the same exact desiccant that is inside those little "DO NOT EAT" packets you find in shoe boxes, foods, electronics, medications, etc. It's used by flower shop to dry flowers and retain the vibrant colors. I use packets of silica gel crystals in an airtight Pelican case where I keep camera equipment. People with gun and ammo safes use it. It's most effective when inside a sealed container, otherwise it's trying to dry out the entire atmosphere. If you drop you smartphone in a puddle, the next stop should be Walmart. Shove the phone into an 8 pound bag of silica kitty litter for a couple of days and it'll dry it completely.
Those little packets can be rejuvenated. The silica will become saturated and won't absorb any more water. When that happens, you can put the packets, or just a layer of the silica gel crystals, on a baking sheet and bake it at 280 degrees for a couple of hours (it won't burn the paper packets). You can cook the rocks in a pot on the stove (please don't add water). I've read where you can do it in the microwave, but I've never tried it. By cooking the rocks, you're cooking the moisture out of the silica, and they can be reused like that indefinitely.
The problem with using silica in socks to prevent or reduce windshield fog for expediting is, the silica will become saturated rather quickly, within a month, for sure, and there's no way to dry them out while on the road (for most people). I tried it a few winters ago, and it worked great, for about a month. That's when the silica became saturated.
You can buy silica packets in all kinds of sizes on Amazon, but those are insanely expensive compared to a 4 or 8 pound bag of silica kitty litter at Walmart. You can use small zip lock plastic bags with 15 or 20 holes punched into it with a pin. You can wrap silica crystals in coffee filters (roll like a burrito, tucking in the sides) and tape or rubber band them closed.
You want 100% silica. If the crystals are blue, the blue dye comes from Cobalt chloride, which is added as an indicator of the absorbed moisture. When fully absorbed with moisture, the blue turns pink, letting you know it's time to cook them. Cobalt chloride is a carcinogenic to humans, and even the smallest amount will kill fish. 100% silica gel is non-toxic. If you must have a color indicating silica gel, get the orange beads, which will turn dark green when fully absorbed. I have a quart of orange silica that I mix a little into the clear kitty litter to use as a visual indicator of when they're full. Of you can get those premade like these. (note those are 15 packets of 33 grams each, 495 total, or about a pound, for $15. You can buy an 8 pound bag of silica kitty litter at Walmart for $10, which is more silica gel that you can use in a lifetime (unless you put it in a pot and pee on it).
1 gram of silica will keep 130 cubic inches dry (a 5x5x5 inch cube).
About 28 grams of silica gel will work for two cubic feet (3456 cubic inches)
2 tablespoons is 28 grams, or about one ounce.
My camera case is 945 cubic inches (15" x 10.5" x 6") and I use a 28 gram packet in there. 7 or 8 grams is all I need, but using 28 means I only have to rejuvenate it one or twice a year or so.
A few words on kitty litter...
Near the end of the video he shows you how to use kitty litter in a sock on the dash to help prevent fog in the first place. One, you need enough socks to go all the way across the bottom of the windshield. One sock won't work, you need 5 or 6. Two, I think the brand in the video is Fresh Step. It doesn't have to be Fresh Step, but it can't be just any ol' kitty litter. It MUST be 100% silica gel kitty litter. 100% silica gel kitty litter is the same exact desiccant that is inside those little "DO NOT EAT" packets you find in shoe boxes, foods, electronics, medications, etc. It's used by flower shop to dry flowers and retain the vibrant colors. I use packets of silica gel crystals in an airtight Pelican case where I keep camera equipment. People with gun and ammo safes use it. It's most effective when inside a sealed container, otherwise it's trying to dry out the entire atmosphere. If you drop you smartphone in a puddle, the next stop should be Walmart. Shove the phone into an 8 pound bag of silica kitty litter for a couple of days and it'll dry it completely.
Those little packets can be rejuvenated. The silica will become saturated and won't absorb any more water. When that happens, you can put the packets, or just a layer of the silica gel crystals, on a baking sheet and bake it at 280 degrees for a couple of hours (it won't burn the paper packets). You can cook the rocks in a pot on the stove (please don't add water). I've read where you can do it in the microwave, but I've never tried it. By cooking the rocks, you're cooking the moisture out of the silica, and they can be reused like that indefinitely.
The problem with using silica in socks to prevent or reduce windshield fog for expediting is, the silica will become saturated rather quickly, within a month, for sure, and there's no way to dry them out while on the road (for most people). I tried it a few winters ago, and it worked great, for about a month. That's when the silica became saturated.
You can buy silica packets in all kinds of sizes on Amazon, but those are insanely expensive compared to a 4 or 8 pound bag of silica kitty litter at Walmart. You can use small zip lock plastic bags with 15 or 20 holes punched into it with a pin. You can wrap silica crystals in coffee filters (roll like a burrito, tucking in the sides) and tape or rubber band them closed.
You want 100% silica. If the crystals are blue, the blue dye comes from Cobalt chloride, which is added as an indicator of the absorbed moisture. When fully absorbed with moisture, the blue turns pink, letting you know it's time to cook them. Cobalt chloride is a carcinogenic to humans, and even the smallest amount will kill fish. 100% silica gel is non-toxic. If you must have a color indicating silica gel, get the orange beads, which will turn dark green when fully absorbed. I have a quart of orange silica that I mix a little into the clear kitty litter to use as a visual indicator of when they're full. Of you can get those premade like these. (note those are 15 packets of 33 grams each, 495 total, or about a pound, for $15. You can buy an 8 pound bag of silica kitty litter at Walmart for $10, which is more silica gel that you can use in a lifetime (unless you put it in a pot and pee on it).
1 gram of silica will keep 130 cubic inches dry (a 5x5x5 inch cube).
About 28 grams of silica gel will work for two cubic feet (3456 cubic inches)
2 tablespoons is 28 grams, or about one ounce.
My camera case is 945 cubic inches (15" x 10.5" x 6") and I use a 28 gram packet in there. 7 or 8 grams is all I need, but using 28 means I only have to rejuvenate it one or twice a year or so.
