The dash sock (silica gel to prevent frost forming on windows)

[duane1]

Lee Valley sells it as well

Silica Gel Dehumidifiers - Lee Valley Tools

[d0sitmatr]

Originally Posted by brucey

I hate having to run the defroster in winter, knowing it's turning on the A/C. As well, my windows fog up easily once more than one person is in the car. I spend a lot of time trying to keep them clear. I like this idea as well!

I have that disabled in my mp5.
but I also have to manually (under the dash) change my venting. not sure how the subi is setup, but on the mazda, when you turn the dial to get it over to the 2 defrost settings, it toggles a little switch on the vent table under the dash. Ive thought of a couple different ways to bypass it and still have the use of my ventswitch on the dash, instead of climbing under it if I want to switch where the air is blowing from, but as it stands now it works pretty darn good.
although, I do have to wait a little extra time for the car to heat up to provide dryer, warm air, its not so terrible as to offset that Im not using the AC unit.

[jakobnev]

Well i went BIG last week and bought 10kg of kitty litter. (I can't believe people spend $20 per month just so their cat can poop)

It was pure silica gel, irregular shape crystals, but it seems just as good as those balls you get in bags. I filled more socks (clean ones without holes this time) and now i can theoretically get 100g of water out of my car per day! And i have to figure out what to do with the other 9kg of this stuff.

[MetroMPG]

Originally Posted by jakobnev

And i have to figure out what to do with the other 9kg of this stuff.

Easy: get a cat!

[Piwoslaw]

I've found a pet shop with silica gel cat litter, but the balls of silica are bigger than the silica gel in the packets found in packages. If I were to crush the cat litter into smaller pieces would the silica gel be more effective by having more surface area?

[euromodder]

Originally Posted by Piwoslaw

If I were to crush the cat litter into smaller pieces would the silica gel be more effective by having more surface area?

Yes, if the balls are solid silica gel.

[Piwoslaw]

About 2-3 months ago I traded my neighbor some car work for a sock full of their cat's silica gel (not used, they claimed). You should have seen the expression on their faces!

Anyhow I have 300g of the stuff, which gives up over 20g of water after 2-3 minutes in the microwave (I've measured only 1-2 times). After heating I let it cool down for 30 minutes. Now, should I take it to the car when I get in, or a bit earlier to get a head start? How long does it take the silica gel to "charge"?

I also noticed that a fine dust comes out of the sock when handling it. Could the crystals be deteriorating in the microwave?

Any other advice on using it?

[euromodder]

Originally Posted by Piwoslaw

Now, should I take it to the car when I get in, or a bit earlier to get a head start? How long does it take the silica gel to "charge"?

You'd best leave it in there and let it soak up the moisture.

I also noticed that a fine dust comes out of the sock when handling it. Could the crystals be deteriorating in the microwave?

That'd be fine silica dust.
Don't inhale it.

Put the microwave on a lower output - lowest possible - and heat it more gently.
Or preferably put it on the heating.
You're likely blowing up the crystals.
Steam is 1200 times more voluminous than liquid water.
If the steam has no time to escape, it'll blow apart whatever tries to contain the expansion.

Any other advice on using it?

Put it in a bag with smaller holes / pores than a sock.

[Florin]

I think that a hygrometer in the cabin is also useful. It is good to see if the sock works and how well.

[Piwoslaw]

Originally Posted by Florin

I think that a hygrometer in the cabin is also useful. It is good to see if the sock works and how well.

The sock I have weighs about 575 grams when I bring it home. After 5-10 minutes of warming in the microwave, when the silica gel has more or less "steamed off", it weighs 25-30g less.

How that translates to keeping the windshield dry is another matter - is this 30g of water which didn't condense on the windows, or is it 30g of water vapour which would have been expelled out of the car anyway?